Documentation Authors: Adam Dudczak, Mathias Düsterhöft, Marcin Grzejszczak, Dennis Kieselhorst, Jakub Kubryński, Karol Lassak, Olga Maciaszek-Sharma, Mariusz Smykuła, Dave Syer
1.1.2.RELEASE
Spring Cloud Contract
What you always need is confidence in pushing new features into a new application or service in a distributed system. This project provides support for Consumer Driven Contracts and service schemas in Spring applications, covering a range of options for writing tests, publishing them as assets, asserting that a contract is kept by producers and consumers, for HTTP and message-based interactions.
Spring Cloud Contract Verifier
Introduction
Tip
|
The Accurest project was initially started by Marcin Grzejszczak and Jakub Kubrynski (codearte.io) |
Just to make long story short - Spring Cloud Contract Verifier is a tool that enables Consumer Driven Contract (CDC) development of JVM-based applications. It is shipped with Contract Definition Language (DSL). Contract definitions are used to produce following resources:
-
JSON stub definitions to be used by WireMock when doing integration testing on the client code (client tests). Test code must still be written by hand, test data is produced by Spring Cloud Contract Verifier.
-
Messaging routes if you’re using one. We’re integrating with Spring Integration, Spring Cloud Stream, Spring AMQP and Apache Camel. You can however set your own integrations if you want to
-
Acceptance tests (in JUnit or Spock) used to verify if server-side implementation of the API is compliant with the contract (server tests). Full test is generated by Spring Cloud Contract Verifier.
Spring Cloud Contract Verifier moves TDD to the level of software architecture.
Why?
Let us assume that we have a system comprising of multiple microservices:
Testing issues
If we wanted to test the application in top left corner if it can communicate with other services then we could do one of two things:
-
deploy all microservices and perform end to end tests
-
mock other microservices in unit / integration tests
Both have their advantages but also a lot of disadvantages. Let’s focus on the latter.
Deploy all microservices and perform end to end tests
Advantages:
-
simulates production
-
tests real communication between services
Disadvantages:
-
to test one microservice we would have to deploy 6 microservices, a couple of databases etc.
-
the environment where the tests would be conducted would be locked for a single suite of tests (i.e. nobody else would be able to run the tests in the meantime).
-
long to run
-
very late feedback
-
extremely hard to debug
Mock other microservices in unit / integration tests
Advantages:
-
very fast feedback
-
no infrastructure requirements
Disadvantages:
-
the implementor of the service creates stubs thus they might have nothing to do with the reality
-
you can go to production with passing tests and failing production
To solve the aforementioned issues Spring Cloud Contract Verifier with Stub Runner were created. Their main idea is to give you very fast feedback, without the need to set up the whole world of microservices. If you work on stubs then the only applications you need are those that your application is using directly.
Spring Cloud Contract Verifier gives you the certainty that the stubs that you’re using were created by the service that you’re calling. Also if you can use them it means that they were tested against the producer’s side. In other words - you can trust those stubs.
Purposes
The main purposes of Spring Cloud Contract Verifier with Stub Runner are:
-
to ensure that WireMock / Messaging stubs (used when developing the client) are doing exactly what actual server-side implementation will do,
-
to promote ATDD method and Microservices architectural style,
-
to provide a way to publish changes in contracts that are immediately visible on both sides,
-
to generate boilerplate test code used on the server side.
Important
|
Spring Cloud Contract Verifier’s purpose is NOT to start writing business features in the contracts. Let’s assume that we have a business use case of fraud check. If a user can be a fraud for 100 different reasons, we would assume that you would create 2 contracts. One for the positive and one for the negative fraud case. Contract tests are used to test contracts between applications and not to simulate full behaviour. |
How
Define the contract
As consumers we need to define what exactly we want to achieve. We need to formulate our expectations. That’s why we write the following contract.
Let’s assume that we’d like to send the request containing the id of the client and the amount he wants to borrow from us. We’d like to send it to the /fraudcheck url via the PUT method.
package contracts
org.springframework.cloud.contract.spec.Contract.make {
request { // (1)
method 'PUT' // (2)
url '/fraudcheck' // (3)
body([ // (4)
"client.id": $(regex('[0-9]{10}')),
loanAmount: 99999
])
headers { // (5)
contentType('application/json')
}
}
response { // (6)
status 200 // (7)
body([ // (8)
fraudCheckStatus: "FRAUD",
"rejection.reason": "Amount too high"
])
headers { // (9)
contentType('application/json')
}
}
}
/*
From the Consumer perspective, when shooting a request in the integration test:
(1) - If the consumer sends a request
(2) - With the "PUT" method
(3) - to the URL "/fraudcheck"
(4) - with the JSON body that
* has a field `clientId` that matches a regular expression `[0-9]{10}`
* has a field `loanAmount` that is equal to `99999`
(5) - with header `Content-Type` equal to `application/json`
(6) - then the response will be sent with
(7) - status equal `200`
(8) - and JSON body equal to
{ "fraudCheckStatus": "FRAUD", "rejectionReason": "Amount too high" }
(9) - with header `Content-Type` equal to `application/json`
From the Producer perspective, in the autogenerated producer-side test:
(1) - A request will be sent to the producer
(2) - With the "PUT" method
(3) - to the URL "/fraudcheck"
(4) - with the JSON body that
* has a field `clientId` that will have a generated value that matches a regular expression `[0-9]{10}`
* has a field `loanAmount` that is equal to `99999`
(5) - with header `Content-Type` equal to `application/json`
(6) - then the test will assert if the response has been sent with
(7) - status equal `200`
(8) - and JSON body equal to
{ "fraudCheckStatus": "FRAUD", "rejectionReason": "Amount too high" }
(9) - with header `Content-Type` matching `application/json.*`
*/
Client Side
Spring Cloud Contract will generate stubs, which you can use during client side testing. You will have a WireMock instance / Messaging route up and running that simulates the service Y. You would like to feed that instance with a proper stub definition.
At some point in time you need to send a request to the Fraud Detection service.
ResponseEntity<FraudServiceResponse> response =
restTemplate.exchange("http://localhost:" + port + "/fraudcheck", HttpMethod.PUT,
new HttpEntity<>(request, httpHeaders),
FraudServiceResponse.class);
Annotate your test class with @AutoConfigureStubRunner
. In the annotation provide the group id and artifact id for the Stub Runner to download stubs of your collaborators.
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"}, workOffline = true)
@DirtiesContext
public class LoanApplicationServiceTests {
After that, during the tests Spring Cloud Contract will automatically find the stubs (simulating the real service) in Maven repository and expose them on configured (or random) port.
Server Side
Being a service Y since you are developing your stub, you need to be sure that it’s actually resembling your concrete implementation. You can’t have a situation where your stub acts in one way and your application on production behaves in a different way.
That’s why from the provided stub acceptance tests will be generated that will ensure that your application behaves in the same way as you define in your stub.
The autogenerated test would look like this:
@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
// given:
MockMvcRequestSpecification request = given()
.header("Content-Type", "application/vnd.fraud.v1+json")
.body("{\"client.id\":\"1234567890\",\"loanAmount\":99999}");
// when:
ResponseOptions response = given().spec(request)
.put("/fraudcheck");
// then:
assertThat(response.statusCode()).isEqualTo(200);
assertThat(response.header("Content-Type")).matches("application/vnd.fraud.v1.json.*");
// and:
DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
assertThatJson(parsedJson).field("['fraudCheckStatus']").matches("[A-Z]{5}");
assertThatJson(parsedJson).field("['rejection.reason']").isEqualTo("Amount too high");
}
Step by step guide to CDC
Let’s take an example of Fraud Detection and Loan Issuance process. The business scenario is such that we want to issue loans to people but don’t want them to steal the money from us. The current implementation of our system grants loans to everybody.
Let’s assume that the Loan Issuance
is a client to the
Fraud Detection
server. In the current sprint we are required to develop a new feature - if a client wants to borrow too much money then we mark him as fraud.
Technical remark - Fraud Detection will have artifact id http-server
, Loan Issuance http-client
and both have group id com.example
.
Social remark - both client and server development teams need to communicate directly and discuss changes while going through the process. CDC is all about communication.
Tip
|
In this case the ownership of the contracts lays on the producer side. It means that physically all the contract are present in the producer’s repository |
Technical note
If using the SNAPSHOT / Milestone / Release Candidate versions please add the following section to your
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
repositories {
mavenCentral()
mavenLocal()
maven { url "http://repo.spring.io/snapshot" }
maven { url "http://repo.spring.io/milestone" }
maven { url "http://repo.spring.io/release" }
}
Consumer side (Loan Issuance)
As a developer of the Loan Issuance service (a consumer of the Fraud Detection server):
start doing TDD by writing a test to your feature
@Test
public void shouldBeRejectedDueToAbnormalLoanAmount() {
// given:
LoanApplication application = new LoanApplication(new Client("1234567890"),
99999);
// when:
LoanApplicationResult loanApplication = service.loanApplication(application);
// then:
assertThat(loanApplication.getLoanApplicationStatus())
.isEqualTo(LoanApplicationStatus.LOAN_APPLICATION_REJECTED);
assertThat(loanApplication.getRejectionReason()).isEqualTo("Amount too high");
}
We’ve just written a test of our new feature. If a loan application for a big amount is received we should reject that loan application with some description.
write the missing implementation
At some point in time you need to send a request to the Fraud Detection service. Let’s assume that we’d like to send the request containing the id of the client and the amount he wants to borrow from us. We’d like to send it to the /fraudcheck
url via the PUT
method.
ResponseEntity<FraudServiceResponse> response =
restTemplate.exchange("http://localhost:" + port + "/fraudcheck", HttpMethod.PUT,
new HttpEntity<>(request, httpHeaders),
FraudServiceResponse.class);
For simplicity we’ve hardcoded the port of the Fraud Detection service at 8080
and our application is running on 8090
.
If we’d start the written test it would obviously break since we have no service running on port 8080
.
clone the Fraud Detection service repository locally
We’ll start playing around with the server side contract. That’s why we need to first clone it.
git clone https://your-git-server.com/server-side.git local-http-server-repo
define the contract locally in the repo of Fraud Detection service
As consumers we need to define what exactly we want to achieve. We need to formulate our expectations. That’s why we write the following contract.
Important
|
We’re placing the contract under src/test/resources/contracts/fraud folder. The fraud folder
is important cause we’ll reference that folder in the producer’s test base class name.
|
package contracts
org.springframework.cloud.contract.spec.Contract.make {
request { // (1)
method 'PUT' // (2)
url '/fraudcheck' // (3)
body([ // (4)
"client.id": $(regex('[0-9]{10}')),
loanAmount: 99999
])
headers { // (5)
contentType('application/json')
}
}
response { // (6)
status 200 // (7)
body([ // (8)
fraudCheckStatus: "FRAUD",
"rejection.reason": "Amount too high"
])
headers { // (9)
contentType('application/json')
}
}
}
/*
From the Consumer perspective, when shooting a request in the integration test:
(1) - If the consumer sends a request
(2) - With the "PUT" method
(3) - to the URL "/fraudcheck"
(4) - with the JSON body that
* has a field `clientId` that matches a regular expression `[0-9]{10}`
* has a field `loanAmount` that is equal to `99999`
(5) - with header `Content-Type` equal to `application/json`
(6) - then the response will be sent with
(7) - status equal `200`
(8) - and JSON body equal to
{ "fraudCheckStatus": "FRAUD", "rejectionReason": "Amount too high" }
(9) - with header `Content-Type` equal to `application/json`
From the Producer perspective, in the autogenerated producer-side test:
(1) - A request will be sent to the producer
(2) - With the "PUT" method
(3) - to the URL "/fraudcheck"
(4) - with the JSON body that
* has a field `clientId` that will have a generated value that matches a regular expression `[0-9]{10}`
* has a field `loanAmount` that is equal to `99999`
(5) - with header `Content-Type` equal to `application/json`
(6) - then the test will assert if the response has been sent with
(7) - status equal `200`
(8) - and JSON body equal to
{ "fraudCheckStatus": "FRAUD", "rejectionReason": "Amount too high" }
(9) - with header `Content-Type` matching `application/json.*`
*/
The Contract is written using a statically typed Groovy DSL. You might be wondering what are those
value(client(…), server(…))
parts. By using this notation Spring Cloud Contract allows you to
define parts of a JSON / URL / etc. which are dynamic. In case of an identifier or a timestamp you
don’t want to hardcode a value. You want to allow some different ranges of values. That’s why for
the consumer side you can set regular expressions matching those values. You can provide the body
either by means of a map notation or String with interpolations.
Consult the docs
for more information. We highly recommend using the map notation!
Tip
|
It’s really important that you understand the map notation to set up contracts. Please read the Groovy docs regarding JSON |
The aforementioned contract is an agreement between two sides that:
-
if an HTTP request is sent with
-
a method
PUT
on an endpoint/fraudcheck
-
JSON body with
client.id
matching the regular expression[0-9]{10}
andloanAmount
equal to99999
-
and with a header
Content-Type
equal toapplication/vnd.fraud.v1+json
-
-
then an HTTP response would be sent to the consumer that
-
has status
200
-
contains JSON body with the
fraudCheckStatus
field containing a valueFRAUD
and therejectionReason
field having valueAmount too high
-
and a
Content-Type
header with a value ofapplication/vnd.fraud.v1+json
-
Once we’re ready to check the API in practice in the integration tests we need to just install the stubs locally
add the Spring Cloud Contract Verifier plugin
We can add either Maven or Gradle plugin - in this example we’ll show how to add Maven. First we need to add the Spring Cloud Contract
BOM.
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Next, the Spring Cloud Contract Verifier
Maven plugin
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example.fraud</packageWithBaseClasses>
</configuration>
</plugin>
Since the plugin was added we get the Spring Cloud Contract Verifier
features which from the provided contracts:
-
generate and run tests
-
produce and install stubs
We don’t want to generate tests since we, as consumers, want only to play with the stubs. That’s why we need to skip the tests generation and execution. When we execute:
cd local-http-server-repo
./mvnw clean install -DskipTests
In the logs we’ll see something like this:
[INFO] --- spring-cloud-contract-maven-plugin:1.0.0.BUILD-SNAPSHOT:generateStubs (default-generateStubs) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar
[INFO]
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:1.5.4.BUILD-SNAPSHOT:repackage (default) @ http-server ---
[INFO]
[INFO] --- maven-install-plugin:2.5.2:install (default-install) @ http-server ---
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.jar
[INFO] Installing /some/path/http-server/pom.xml to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.pom
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
This line is extremely important
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
It’s confirming that the stubs of the http-server
have been installed in the local repository.
run the integration tests
In order to profit from the Spring Cloud Contract Stub Runner functionality of automatic stub downloading you have to do the following in our consumer side project (Loan Application service
).
Add the Spring Cloud Contract
BOM
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Add the dependency to Spring Cloud Contract Stub Runner
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-contract-stub-runner</artifactId>
<scope>test</scope>
</dependency>
Annotate your test class with @AutoConfigureStubRunner
. In the annotation provide the group id and artifact id for the Stub Runner to download stubs of your collaborators. Also provide the offline work switch since you’re playing with the collaborators offline (optional step).
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"}, workOffline = true)
@DirtiesContext
public class LoanApplicationServiceTests {
Now if you run your tests you’ll see sth like this:
2016-07-19 14:22:25.403 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Desired version is + - will try to resolve the latest version
2016-07-19 14:22:25.438 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Resolved version is 0.0.1-SNAPSHOT
2016-07-19 14:22:25.439 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Resolving artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT using remote repositories []
2016-07-19 14:22:25.451 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Resolved artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
2016-07-19 14:22:25.465 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Unpacking stub from JAR [URI: file:/path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar]
2016-07-19 14:22:25.475 INFO 41050 --- [ main] o.s.c.c.stubrunner.AetherStubDownloader : Unpacked file to [/var/folders/0p/xwq47sq106x1_g3dtv6qfm940000gq/T/contracts100276532569594265]
2016-07-19 14:22:27.737 INFO 41050 --- [ main] o.s.c.c.stubrunner.StubRunnerExecutor : All stubs are now running RunningStubs [namesAndPorts={com.example:http-server:0.0.1-SNAPSHOT:stubs=8080}]
Which means that Stub Runner has found your stubs and started a server for app with group id com.example
, artifact id http-server
with version 0.0.1-SNAPSHOT
of the stubs and with stubs
classifier on port 8080
.
file a PR
What we did until now is an iterative process. We can play around with the contract, install it locally and work on the consumer side until we’re happy with the contract.
Once we’re satisfied with the results and the test passes publish a PR to the server side. Currently the consumer side work is done.
Producer side (Fraud Detection server)
As a developer of the Fraud Detection server (a server to the Loan Issuance service):
initial implementation
As a reminder here you can see the initial implementation
@RequestMapping(value = "/fraudcheck", method = PUT)
public FraudCheckResult fraudCheck(@RequestBody FraudCheck fraudCheck) {
return new FraudCheckResult(FraudCheckStatus.OK, NO_REASON);
}
take over the PR
git checkout -b contract-change-pr master
git pull https://your-git-server.com/server-side-fork.git contract-change-pr
You have to add the dependencies needed by the autogenerated tests
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-contract-verifier</artifactId>
<scope>test</scope>
</dependency>
In the configuration of the Maven plugin we passed the packageWithBaseClasses
property
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example.fraud</packageWithBaseClasses>
</configuration>
</plugin>
Important
|
We’ve decided to use the "convention based" naming by setting the packageWithBaseClasses property.
That means that 2 last packages will be combined into a name of the base test class. In our case the contracts
were placed under src/test/resources/contracts/fraud . Since we don’t have 2 packages starting from the contracts
folder we’re picking only one which is fraud . We’re adding the Base suffix and we’re capitalizing fraud .
That gives us the FraudBase test class name.
|
That’s because all the generated tests will extend that class. Over there you can set up your Spring Context or
whatever is necessary. In our case we’re using Rest Assured MVC to start the server side FraudDetectionController
.
package com.example.fraud;
import org.junit.Before;
import io.restassured.module.mockmvc.RestAssuredMockMvc;
public class FraudBase {
@Before
public void setup() {
RestAssuredMockMvc.standaloneSetup(new FraudDetectionController(),
new FraudStatsController(stubbedStatsProvider()));
}
private StatsProvider stubbedStatsProvider() {
return fraudType -> {
switch (fraudType) {
case DRUNKS:
return 100;
case ALL:
return 200;
}
return 0;
};
}
public void assertThatRejectionReasonIsNull(Object rejectionReason) {
assert rejectionReason == null;
}
}
Now, if you run the ./mvnw clean install
you would get sth like this:
Results :
Tests in error:
ContractVerifierTest.validate_shouldMarkClientAsFraud:32 » IllegalState Parsed...
That’s because you have a new contract from which a test was generated and it failed since you haven’t implemented the feature. The autogenerated test would look like this:
@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
// given:
MockMvcRequestSpecification request = given()
.header("Content-Type", "application/vnd.fraud.v1+json")
.body("{\"client.id\":\"1234567890\",\"loanAmount\":99999}");
// when:
ResponseOptions response = given().spec(request)
.put("/fraudcheck");
// then:
assertThat(response.statusCode()).isEqualTo(200);
assertThat(response.header("Content-Type")).matches("application/vnd.fraud.v1.json.*");
// and:
DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
assertThatJson(parsedJson).field("['fraudCheckStatus']").matches("[A-Z]{5}");
assertThatJson(parsedJson).field("['rejection.reason']").isEqualTo("Amount too high");
}
As you can see all the producer()
parts of the Contract that were present in the value(consumer(…), producer(…))
blocks got injected into the test.
What’s important here to note is that on the producer side we also are doing TDD. We have expectations in form of a test. This test is shooting a request to our own application to an URL, headers and body defined in the contract. It also is expecting very precisely defined values in the response. In other words you have is your red
part of red
, green
and refactor
. Time to convert the red
into the green
.
write the missing implementation
Now since we now what is the expected input and expected output let’s write the missing implementation.
@RequestMapping(value = "/fraudcheck", method = PUT)
public FraudCheckResult fraudCheck(@RequestBody FraudCheck fraudCheck) {
if (amountGreaterThanThreshold(fraudCheck)) {
return new FraudCheckResult(FraudCheckStatus.FRAUD, AMOUNT_TOO_HIGH);
}
return new FraudCheckResult(FraudCheckStatus.OK, NO_REASON);
}
If we execute ./mvnw clean install
again the tests will pass. Since the Spring Cloud Contract Verifier
plugin adds the tests to the generated-test-sources
you can actually run those tests from your IDE.
deploy your app
Once you’ve finished your work it’s time to deploy your change. First merge the branch
git checkout master
git merge --no-ff contract-change-pr
git push origin master
Then we assume that your CI would run sth like ./mvnw clean deploy
which would publish both the application and the stub artifcats.
Consumer side (Loan Issuance) final step
As a developer of the Loan Issuance service (a consumer of the Fraud Detection server):
merge branch to master
git checkout master
git merge --no-ff contract-change-pr
work online
Now you can disable the offline work for Spring Cloud Contract Stub Runner and provide where the repository with your stubs is placed. At this moment the stubs of the server side will be automatically downloaded from Nexus / Artifactory.
You can switch off the value of the workOffline
parameter in your annotation. Below you can see an
example of achieving the same by changing the properties.
stubrunner:
ids: 'com.example:http-server-dsl:+:stubs:8080'
repositoryRoot: http://repo.spring.io/libs-snapshot
And that’s it!
Dependencies
The best way to add the dependencies is to just use the proper starter
dependency.
For stub-runner
use spring-cloud-starter-stub-runner
and when you’re using a plugin just add
spring-cloud-starter-contract-verifier
.
Additional links
Below you can find some resources related to Spring Cloud Contract Verifier and Stub Runner. Note that some can be outdated since the Spring Cloud Contract Verifier project is under constant development.
Spring Cloud Contract video
You can check out the video from the Warsaw JUG about Spring Cloud Contract:
Samples
Here you can find some samples.
FAQ
Why use Spring Cloud Contract Verifier and not X ?
For the time being Spring Cloud Contract Verifier is a JVM based tool. So it could be your first pick when you’re already creating software for the JVM. This project has a lot of really interesting features but especially quite a few of them definitely make Spring Cloud Contract Verifier stand out on the "market" of Consumer Driven Contract (CDC) tooling. Out of many the most interesting are:
-
Possibility to do CDC with messaging
-
Clear and easy to use, statically typed DSL
-
Possibility to copy paste your current JSON file to the contract and only edit its elements
-
Automatic generation of tests from the defined Contract
-
Stub Runner functionality - the stubs are automatically downloaded at runtime from Nexus / Artifactory
-
Spring Cloud integration - no discovery service is needed for integration tests
What is this value(consumer(), producer()) ?
One of the biggest challenges related to stubs is their reusability. Only if they can be vastly used, will they serve their purpose. What typically makes that difficult are the hard-coded values of request / response elements. For example dates or ids. Imagine the following JSON request
{
"time" : "2016-10-10 20:10:15",
"id" : "9febab1c-6f36-4a0b-88d6-3b6a6d81cd4a",
"body" : "foo"
}
and JSON response
{
"time" : "2016-10-10 21:10:15",
"id" : "c4231e1f-3ca9-48d3-b7e7-567d55f0d051",
"body" : "bar"
}
Imagine the pain required to set proper value of the time
field (let’s assume that this content is generated by the
database) by changing the clock in the system or providing stub implementations of data providers. The same is related
to the field called id
. Will you create a stubbed implementation of UUID generator? Makes little sense…
So as a consumer you would like to send a request that matches any form of a time or any UUID. That way your system
will work as usual - will generate data and you won’t have to stub anything out. Let’s assume that in case of the aforementioned
JSON the most important part is the body
field. You can focus on that and provide matching for other fields. In other words
you would like the stub to work like this:
{
"time" : "SOMETHING THAT MATCHES TIME",
"id" : "SOMETHING THAT MATCHES UUID",
"body" : "foo"
}
As far as the response goes as a consumer you need a concrete value that you can operate on. So such a JSON is valid
{
"time" : "2016-10-10 21:10:15",
"id" : "c4231e1f-3ca9-48d3-b7e7-567d55f0d051",
"body" : "bar"
}
As you could see in the previous sections we generate tests from contracts. So from the producer’s side the situation looks much different. We’re parsing the provided contract and in the test we want to send a real request to your endpoints. So for the case of a producer for the request we can’t have any sort of matching. We need concrete values that the producer’s backend can work on. Such a JSON would be a valid one:
{
"time" : "2016-10-10 20:10:15",
"id" : "9febab1c-6f36-4a0b-88d6-3b6a6d81cd4a",
"body" : "foo"
}
On the other hand from the point of view of the validity of the contract the response doesn’t necessarily have to
contain concrete values of time
or id
. Let’s say that you generate those on the producer side - again, you’d
have to do a lot of stubbing to ensure that you always return the same values. That’s why from the producer’s side
what you might want is the following response:
{
"time" : "SOMETHING THAT MATCHES TIME",
"id" : "SOMETHING THAT MATCHES UUID",
"body" : "bar"
}
How can you then provide one time a matcher for the consumer and a concrete value for the producer and vice versa? In Spring Cloud Contract we’re allowing you to provide a dynamic value. That means that it can differ for both sides of the communication. You can pass the values:
Either via the value
method
value(consumer(...), producer(...))
value(stub(...), test(...))
value(client(...), server(...))
or using the $()
method
$(consumer(...), producer(...))
$(stub(...), test(...))
$(client(...), server(...))
You can read more about this in the Contract DSL section.
Calling value()
or $()
tells Spring Cloud Contract that you will be passing a dynamic value.
Inside the consumer()
method you pass the value that should be used on the consumer side (in the generated stub).
Inside the producer()
method you pass the value that should be used on the producer side (in the generated test).
Tip
|
If on one side you have passed the regular expression and you haven’t passed the other, then the other side will get auto-generated. |
Most often you will use that method together with the regex
helper method. E.g. consumer(regex('[0-9]{10}'))
.
To sum it up the contract for the aforementioned scenario would look more or less like this (the regular expression for time and UUID are simplified and most likely invalid but we want to keep things very simple in this example):
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'GET'
url '/someUrl'
body([
time : value(consumer(regex('[0-9]{4}-[0-9]{2}-[0-9]{2} [0-2][0-9]-[0-5][0-9]-[0-5][0-9]')),
id: value(consumer(regex('[0-9a-zA-z]{8}-[0-9a-zA-z]{4}-[0-9a-zA-z]{4}-[0-9a-zA-z]{12}'))
body: "foo"
])
}
response {
status 200
body([
time : value(producer(regex('[0-9]{4}-[0-9]{2}-[0-9]{2} [0-2][0-9]-[0-5][0-9]-[0-5][0-9]')),
id: value([producer(regex('[0-9a-zA-z]{8}-[0-9a-zA-z]{4}-[0-9a-zA-z]{4}-[0-9a-zA-z]{12}'))
body: "bar"
])
}
}
Important
|
Please read the Groovy docs related to JSON to understand how to properly structure the request / response bodies. |
How to do Stubs versioning?
API Versioning
Let’s try to answer a question what versioning really means. If you’re referring to the API version then there are different approaches.
-
use Hypermedia, links and do not version your API by any means
-
pass versions through headers / urls
I will not try to answer a question which approach is better. Whatever suit your needs and allows you to generate business value should be picked.
Let’s assume that you do version your API. In that case you should provide as many contracts as many versions you support. You can create a subfolder for every version or append it to th contract name - whatever suits you more.
JAR versioning
If by versioning you mean the version of the JAR that contains the stubs then there are essentially two main approaches.
Let’s assume that you’re doing Continuous Delivery / Deployment which means that you’re generating a new version of the jar each time you go through the pipeline and that jar can go to production at any time. For example your jar version looks like this (it got built on the 20.10.2016 at 20:15:21) :
1.0.0.20161020-201521-RELEASE
In that case your generated stub jar will look like this.
1.0.0.20161020-201521-RELEASE-stubs.jar
In this case you should inside your application.yml
or @AutoConfigureStubRunner
when referencing stubs provide the
latest version of the stubs. You can do that by passing the +
sign. Example
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:8080"})
If the versioning however is fixed (e.g. 1.0.4.RELEASE
or 2.1.1
) then you have to set the concrete value of the jar
version. Example for 2.1.1.
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:2.1.1:stubs:8080"})
Dev or prod stubs
You can manipulate the classifier to run the tests against current development version of the stubs of other services
or the ones that were deployed to production. If you alter your build to deploy the stubs with the prod-stubs
classifier
once you reach production deployment then you can run tests in one case with dev stubs and one with prod stubs.
Example of tests using development version of stubs
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:8080"})
Example of tests using production version of stubs
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:prod-stubs:8080"})
You can pass those values also via properties from your deployment pipeline.
Common repo with contracts
Another way of storing contracts other than having them with the producer is keeping them in a common place. It can be related to security issues where the consumers can’t clone the producer’s code. Also if you keep contracts in a single place then you, as a producer, will know how many consumers you have and which consumer will you break with your local changes.
Repo structure
Let’s assume that we have a producer with coordinates com.example:server
and 3 consumers: client1
,
client2
, client3
. Then in the repository with common contracts you would have the following setup
(which you can checkout here:
├── com
│ └── example
│ └── server
│ ├── client1
│ │ └── expectation.groovy
│ ├── client2
│ │ └── expectation.groovy
│ ├── client3
│ │ └── expectation.groovy
│ └── pom.xml
├── mvnw
├── mvnw.cmd
├── pom.xml
└── src
└── assembly
└── contracts.xml
As you can see the under the slash-delimited groupid /
artifact id folder (com/example/server
) you have
expectations of the 3 consumers (client1
, client2
and client3
). Expectations are the standard Groovy DSL
contract files as described throughout this documentation. This repository has to produce a JAR file that maps
one to one to the contents of the repo.
Example of a pom.xml
inside the server
folder.
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Server Stubs</name>
<description>POM used to install locally stubs for consumer side</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
<relativePath />
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
<spring-cloud-contract.version>1.2.0.BUILD-SNAPSHOT</spring-cloud-contract.version>
<spring-cloud-dependencies.version>Edgware.BUILD-SNAPSHOT</spring-cloud-dependencies.version>
<excludeBuildFolders>true</excludeBuildFolders>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<!-- By default it would search under src/test/resources/ -->
<contractsDirectory>${project.basedir}</contractsDirectory>
</configuration>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>
As you can see there are no dependencies other than the Spring Cloud Contract Maven Plugin.
Those poms are necessary for the consumer side to run mvn clean install -DskipTests
to locally install
stubs of the producer project.
The pom.xml
in the root folder can look like this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example.standalone</groupId>
<artifactId>contracts</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>Contracts</name>
<description>Contains all the Spring Cloud Contracts, well, contracts. JAR used by the producers to generate tests and stubs</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<id>contracts</id>
<phase>prepare-package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<attach>true</attach>
<descriptor>${basedir}/src/assembly/contracts.xml</descriptor>
<!-- If you want an explicit classifier remove the following line -->
<appendAssemblyId>false</appendAssemblyId>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
It’s using the assembly plugin in order to build the JAR with all the contracts. Example of such setup is here:
<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
<id>project</id>
<formats>
<format>jar</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<fileSets>
<fileSet>
<directory>${project.basedir}</directory>
<outputDirectory>/</outputDirectory>
<useDefaultExcludes>true</useDefaultExcludes>
<excludes>
<exclude>**/${project.build.directory}/**</exclude>
<exclude>mvnw</exclude>
<exclude>mvnw.cmd</exclude>
<exclude>.mvn/**</exclude>
<exclude>src/**</exclude>
</excludes>
</fileSet>
</fileSets>
</assembly>
Workflow
The workflow would look similar to the one presented in the Step by step guide to CDC
. The only difference
is that the producer doesn’t own the contracts anymore. So the consumer and the producer have to work on
common contracts in a common repository.
Consumer
When the consumer wants to work on the contracts offline, instead of cloning the producer code, the
consumer team clones the common repository, goes to the required producer’s folder (e.g. com/example/server
)
and runs mvn clean install -DskipTests
to install locally the stubs converted from the contracts.
Tip
|
You need to have Maven installed locally |
Producer
As a producer it’s enough to alter the Spring Cloud Contract Verifier to provide the URL and the dependency of the JAR containing the contracts:
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<configuration>
<contractsRepositoryUrl>http://link/to/your/nexus/or/artifactory/or/sth</contractsRepositoryUrl>
<contractDependency>
<groupId>com.example.standalone</groupId>
<artifactId>contracts</artifactId>
</contractDependency>
</configuration>
</plugin>
With this setup the JAR with groupid com.example.standalone
and artifactid contracts
will be downloaded
from http://link/to/your/nexus/or/artifactory/or/sth
. It will be then unpacked in a local temporary folder
and contracts present under the com/example/server
will be picked as the ones used to generate the
tests and the stubs. Due to this convention the producer team will know which consumer teams will be broken
when some incompatible changes are done.
The rest of the flow looks the same.
Can I have multiple base classes for tests?
Yes! Check out the Different base classes for contracts sections of either Gradle or Maven plugins.
How can I debug the request/response being sent by the generated tests client?
The generated tests all boil down to RestAssured in some form or fashion which relies on Apache HttpClient. HttpClient has a facility called wire logging which logs the entire request and response to HttpClient. Spring Boot has a logging common application property for doing this sort of thing, just add this to your application properties
logging.level.org.apache.http.wire=DEBUG
Can I reference the request from the response?
Yes! With version 1.1.0 we’ve added such a possibility. On the HTTP stub server side we’re providing support for this for WireMock. In case of other HTTP server stubs you’ll have to implement the approach yourself.
Spring Cloud Contract Verifier HTTP
Gradle Project
Prerequisites
In order to use Spring Cloud Contract Verifier with WireMock you have to use Gradle or Maven plugin.
Warning
|
If you want to use Spock in your projects you have to add separately
the spock-core and spock-spring modules. Check Spock docs for more information
|
Add gradle plugin with dependencies
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:${springboot_version}"
classpath "org.springframework.cloud:spring-cloud-contract-gradle-plugin:${verifier_version}"
}
}
apply plugin: 'groovy'
apply plugin: 'spring-cloud-contract'
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-contract-dependencies:${verifier_version}"
}
}
dependencies {
testCompile 'org.codehaus.groovy:groovy-all:2.4.6'
// example with adding Spock core and Spock Spring
testCompile 'org.spockframework:spock-core:1.0-groovy-2.4'
testCompile 'org.spockframework:spock-spring:1.0-groovy-2.4'
testCompile 'org.springframework.cloud:spring-cloud-starter-contract-verifier'
}
Gradle and Rest Assured 3.0
By default Rest Assured 2.x is added to the classpath. However in order to give the users the opportunity to use Rest Assured 3.x it’s enough to add it to the plugins classpath.
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:${springboot_version}"
classpath "org.springframework.cloud:spring-cloud-contract-gradle-plugin:${verifier_version}"
classpath "io.rest-assured:rest-assured:3.0.2"
classpath "io.rest-assured:spring-mock-mvc:3.0.2"
}
}
depenendencies {
// all dependencies
// you can exclude rest-assured from spring-cloud-contract-verifier
testCompile "io.rest-assured:rest-assured:3.0.2"
testCompile "io.rest-assured:spring-mock-mvc:3.0.2"
}
That way the plugin will automatically see that Rest Assured 3.x is present on the classpath and will modify the imports accordingly.
Snapshot versions for Gradle
Add the additional snapshot repository to your build.gradle to use snapshot versions which are automatically uploaded after every successful build:
buildscript {
repositories {
mavenCentral()
mavenLocal()
maven { url "http://repo.spring.io/snapshot" }
maven { url "http://repo.spring.io/milestone" }
maven { url "http://repo.spring.io/release" }
}
}
Add stubs
By default Spring Cloud Contract Verifier is looking for stubs in src/test/resources/contracts
directory.
Directory containing stub definitions is treated as a class name, and each stub definition is treated as a single test. We assume that it contains at least one directory which will be used as test class name. If there is more than one level of nested directories all except the last one will be used as package name. So with following structure
src/test/resources/contracts/myservice/shouldCreateUser.groovy
src/test/resources/contracts/myservice/shouldReturnUser.groovy
Spring Cloud Contract Verifier will create test class defaultBasePackage.MyService
with two methods
-
shouldCreateUser()
-
shouldReturnUser()
Run plugin
Plugin registers itself to be invoked before check
task. You have nothing to do as long as you want it to be part of your build process. If you just want to generate tests please invoke generateContractTests
task.
Default setup
Default Gradle Plugin setup creates the following Gradle part of the build (it’s a pseudocode)
contracts {
targetFramework = 'JUNIT'
testMode = 'MockMvc'
generatedTestSourcesDir = project.file("${project.buildDir}/generated-test-sources/contracts")
contractsDslDir = "${project.rootDir}/src/test/resources/contracts"
basePackageForTests = 'org.springframework.cloud.verifier.tests'
stubsOutputDir = project.file("${project.buildDir}/stubs")
// the following properties are used when you want to provide where the JAR with contract lays
contractDependency {
stringNotation = ''
}
contractsPath = ''
contractsWorkOffline = false
contractRepository {
cacheDownloadedContracts(true)
}
}
tasks.create(type: Jar, name: 'verifierStubsJar', dependsOn: 'generateClientStubs') {
baseName = project.name
classifier = contracts.stubsSuffix
from contractVerifier.stubsOutputDir
}
project.artifacts {
archives task
}
tasks.create(type: Copy, name: 'copyContracts') {
from contracts.contractsDslDir
into contracts.stubsOutputDir
}
verifierStubsJar.dependsOn 'copyContracts'
publishing {
publications {
stubs(MavenPublication) {
artifactId project.name
artifact verifierStubsJar
}
}
}
Configure plugin
To change default configuration just add contracts
snippet to your Gradle config
contracts {
testMode = 'MockMvc'
baseClassForTests = 'org.mycompany.tests'
generatedTestSourcesDir = project.file('src/generatedContract')
}
Configuration options
-
testMode - defines mode for acceptance tests. By default MockMvc which is based on Spring’s MockMvc. It can also be changed to JaxRsClient or to Explicit for real HTTP calls.
-
imports - array with imports that should be included in generated tests (for example ['org.myorg.Matchers']). By default empty array []
-
staticImports - array with static imports that should be included in generated tests(for example ['org.myorg.Matchers.*']). By default empty array []
-
basePackageForTests - specifies base package for all generated tests. By default set to org.springframework.cloud.verifier.tests
-
baseClassForTests - base class for all generated tests. By default
spock.lang.Specification
if using Spock tests. -
packageWithBaseClasses - instead of providing a fixed value for base class you can provide a package where all the base classes lay. Takes precedence over baseClassForTests.
-
baseClassMappings - explicitly map contract package to a FQN of a base class. Takes precedence over packageWithBaseClasses and baseClassForTests.
-
ruleClassForTests - specifies Rule which should be added to generated test classes.
-
ignoredFiles - Ant matcher allowing defining stub files for which processing should be skipped. By default empty array []
-
contractsDslDir - directory containing contracts written using the GroovyDSL. By default
$rootDir/src/test/resources/contracts
-
generatedTestSourcesDir - test source directory where tests generated from Groovy DSL should be placed. By default
$buildDir/generated-test-sources/contractVerifier
-
stubsOutputDir - dir where the generated WireMock stubs from Groovy DSL should be placed
-
targetFramework - the target test framework to be used; currently Spock and JUnit are supported with JUnit being the default framework
The following properties are used when you want to provide where the JAR with contract lays
-
contractDependency - the Dependency that provides
groupid:artifactid:version:classifier
coordinates. You can use thecontractDependency
closure to set it up -
contractsPath - if contract deps are downloaded will default to
groupid/artifactid
wheregroupid
will be slash separated. Otherwise will scan contracts under provided directory -
contractsWorkOffline - in order not to download the dependencies each time you can download them once and work offline afterwards (reuse local Maven repo)
Single base class for all tests
When using Spring Cloud Contract Verifier in default MockMvc you need to create a base specification for all generated acceptance tests. In this class you need to point to endpoint which should be verified.
abstract class BaseMockMvcSpec extends Specification {
def setup() {
RestAssuredMockMvc.standaloneSetup(new PairIdController())
}
void isProperCorrelationId(Integer correlationId) {
assert correlationId == 123456
}
void isEmpty(String value) {
assert value == null
}
}
In case of using Explicit
mode, you can use base class to initialize the whole tested app similarly as in regular integration tests. In case of JAXRSCLIENT
mode this base class
should also contain protected WebTarget webTarget
field, right now the only option to test JAX-RS API is to start a web server.
Different base classes for contracts
If your base classes differ between contracts you can tell the Spring Cloud Contract plugin which class should get extended by the autogenerated tests. You have two options:
-
follow a convention by providing the
packageWithBaseClasses
-
provide explicit mapping via
baseClassMappings
Convention
The convention is such that if you have a contract under e.g. src/test/resources/contract/foo/bar/baz/
and provide the value of the packageWithBaseClasses
property
to com.example.base
then we will assume that there is a BarBazBase
class under com.example.base
package. In other words we take last two parts of package
if they exist and form a class with a Base
suffix. Takes precedence over baseClassForTests. Example of usage in the contracts
closure:
packageWithBaseClasses = 'com.example.base'
Mapping
You can manually map a regular expression of the contract’s package to fully qualified name of the base class for the matched contract. Let’s take a look at the following example:
baseClassForTests = "com.example.FooBase"
baseClassMappings {
baseClassMapping('.*/com/.*', 'com.example.ComBase')
baseClassMapping('.*/bar/.*':'com.example.BarBase')
}
Let’s assume that you have contracts under
- src/test/resources/contract/com/
- src/test/resources/contract/foo/
By providing the baseClassForTests
we have a fallback in case mapping didn’t succeed (you could also provide
the packageWithBaseClasses
as fallback). That way the tests generated from src/test/resources/contract/com/
contracts
will be extending the com.example.ComBase
whereas the rest of tests will extend com.example.FooBase
.
Invoking generated tests
To ensure that provider side is complaint with defined contracts, you need to invoke:
./gradlew generateContractTests test
Spring Cloud Contract Verifier on consumer side
In consumer service you need to configure Spring Cloud Contract Verifier plugin in exactly the same way as in case of provider. If you don’t want to use Stub Runner then you need to copy contracts stored in
src/test/resources/contracts
and generate WireMock json stubs using:
./gradlew generateClientStubs
Note that stubsOutputDir
option has to be set for stub generation to work.
When present, json stubs can be used in consumer automated tests.
@ContextConfiguration(loader == SpringApplicationContextLoader, classes == Application)
class LoanApplicationServiceSpec extends Specification {
@ClassRule
@Shared
WireMockClassRule wireMockRule == new WireMockClassRule()
@Autowired
LoanApplicationService sut
def 'should successfully apply for loan'() {
given:
LoanApplication application =
new LoanApplication(client: new Client(clientPesel: '12345678901'), amount: 123.123)
when:
LoanApplicationResult loanApplication == sut.loanApplication(application)
then:
loanApplication.loanApplicationStatus == LoanApplicationStatus.LOAN_APPLIED
loanApplication.rejectionReason == null
}
}
Underneath LoanApplication makes a call to FraudDetection service. This request is handled by WireMock server configured using stubs generated by Spring Cloud Contract Verifier.
Using in your Maven project
Add maven plugin
Add the Spring Cloud Contract BOM
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud-dependencies.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
Next, the Spring Cloud Contract Verifier
Maven plugin
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example.fraud</packageWithBaseClasses>
</configuration>
</plugin>
You can read more in the Spring Cloud Contract Maven Plugin Docs
Maven and Rest Assured 3.0
By default Rest Assured 2.x is added to the classpath. However in order to give the users the opportunity to use Rest Assured 3.x it’s enough to add it to the plugins classpath.
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example</packageWithBaseClasses>
</configuration>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-verifier</artifactId>
<version>${spring-cloud-contract.version}</version>
</dependency>
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>rest-assured</artifactId>
<version>3.0.2</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>spring-mock-mvc</artifactId>
<version>3.0.2</version>
<scope>compile</scope>
</dependency>
</dependencies>
</plugin>
<dependencies>
<!-- all dependencies -->
<!-- you can exclude rest-assured from spring-cloud-contract-verifier -->
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>rest-assured</artifactId>
<version>3.0.2</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.rest-assured</groupId>
<artifactId>spring-mock-mvc</artifactId>
<version>3.0.2</version>
<scope>test</scope>
</dependency>
</dependencies>
That way the plugin will automatically see that Rest Assured 3.x is present on the classpath and will modify the imports accordingly.
Snapshot versions for Maven
For Snapshot / Milestone versions you have to add the following section to your pom.xml
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
Add stubs
By default Spring Cloud Contract Verifier is looking for stubs in src/test/resources/contracts
directory.
Directory containing stub definitions is treated as a class name, and each stub definition is treated as a single test.
We assume that it contains at least one directory which will be used as test class name. If there is more than one level of nested directories all except the last one will be used as package name.
So with following structure
src/test/resources/contracts/myservice/shouldCreateUser.groovy
src/test/resources/contracts/myservice/shouldReturnUser.groovy
Spring Cloud Contract Verifier will create test class defaultBasePackage.MyService
with two methods
- shouldCreateUser()
- shouldReturnUser()
Run plugin
Plugin goal generateTests
is assigned to be invoked in phase generate-test-sources
. You have nothing to do as long as you want it to be part of your build process. If you just want to generate tests please invoke generateTests
goal.
Configure plugin
To change default configuration just add configuration
section to plugin definition or execution
definition.
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>convert</goal>
<goal>generateStubs</goal>
<goal>generateTests</goal>
</goals>
</execution>
</executions>
<configuration>
<basePackageForTests>org.springframework.cloud.verifier.twitter.place</basePackageForTests>
<baseClassForTests>org.springframework.cloud.verifier.twitter.place.BaseMockMvcSpec</baseClassForTests>
</configuration>
</plugin>
Important configuration options
-
testMode - defines mode for acceptance tests. By default
MockMvc
which is based on Spring’s MockMvc. It can also be changed toJaxRsClient
or toExplicit
for real HTTP calls. -
basePackageForTests - specifies base package for all generated tests. By default set to
org.springframework.cloud.verifier.tests
. -
ruleClassForTests - specifies Rule which should be added to generated test classes.
-
baseClassForTests - base class for generated tests. By default
spock.lang.Specification
if using Spock tests. -
contractsDirectory - directory containing contracts written using the GroovyDSL. By default
/src/test/resources/contracts
. -
testFramework - the target test framework to be used; currently Spock and JUnit are supported with JUnit being the default framework
-
packageWithBaseClasses - instead of providing a fixed value for base class you can provide a package where all the base classes lay. The convention is such that if you have a contract under
src/test/resources/contract/foo/bar/baz/
and provide the value of this property tocom.example.base
then we will assume that there is aBarBazBase
class undercom.example.base
package. Takes precedence over baseClassForTests -
baseClassMappings - list of base class mappings that where you have to provide
contractPackageRegex
which is checked against the package in which the contract lays andbaseClassFQN
that maps to fully qualified name of the base class for the matched contract. If you have a contract undersrc/test/resources/contract/foo/bar/baz/
and map the property.*
→com.example.base.BaseClass
then the test class generated from these contracts will extendcom.example.base.BaseClass
. Takes precedence over packageWithBaseClasses and baseClassForTests.
If you want to download your contract definitions from a Maven repository you can use
-
contractDependency - the contract dependency that contains all the packaged contracts
-
contractsPath - path to concrete contracts in the JAR with packaged contracts. Defaults to
groupid/artifactid
wheregropuid
is slash separated. -
contractsWorkOffline - if the dependencies should be downloaded or local Maven only should be reused
-
contractsRepositoryUrl - DEPRECATED PROPERTY - please use the
contractRepository
closure - URL to a repo with the artifacts with contracts, if not provided should use the current Maven ones -
contractRepository - closure where you can define properties related to repository with contracts
-
username - username to be used to connect to the repo
-
password - username to be used to connect to the repo
-
proxyHost - proxy host to be used to connect to the repo
-
proxyPort - proxy port to be used to connect to the repo
-
cacheDownloadedContracts - if you want to reuse download JARs that contain contract definitions. We cache only non-snapshot, explicitly provided versions (e.g.
+
or1.0.0.BUILD-SNAPSHOT
won’t get cached). By default this feature is turned on.
-
Single base class for all tests
When using Spring Cloud Contract Verifier in default MockMvc you need to create a base specification for all generated acceptance tests. In this class you need to point to endpoint which should be verified.
package org.mycompany.tests
import org.mycompany.ExampleSpringController
import com.jayway.restassured.module.mockmvc.RestAssuredMockMvc
import spock.lang.Specification
class MvcSpec extends Specification {
def setup() {
RestAssuredMockMvc.standaloneSetup(new ExampleSpringController())
}
}
In case of using Explicit
mode, you can use base class to initialize the whole tested app similarly as in regular integration tests. In case of JAXRSCLIENT
mode this base class should also contain protected WebTarget webTarget
field, right now the only option to test JAX-RS API is to start a web server.
Different base classes for contracts
If your base classes differ between contracts you can tell the Spring Cloud Contract plugin which class should get extended by the autogenerated tests. You have two options:
-
follow a convention by providing the
packageWithBaseClasses
-
provide explicit mapping via
baseClassMappings
Convention
The convention is such that if you have a contract under e.g. src/test/resources/contract/hello/v1/
and provide the value of the packageWithBaseClasses
property
to hello
then we will assume that there is a HelloV1Base
class under hello
package. In other words we take last two parts of package
if they exist and form a class with a Base
suffix. Takes precedence over baseClassForTests. Example of usage:
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<configuration>
<packageWithBaseClasses>hello</packageWithBaseClasses>
</configuration>
</plugin>
Mapping
You can manually map a regular expression of the contract’s package to fully qualified name of the base class for the matched contract.
You have to provide a list baseClassMappings
of baseClassMapping
that takes a contractPackageRegex
to baseClassFQN
mapping.
Let’s take a look at the following example:
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<configuration>
<baseClassForTests>com.example.FooBase</baseClassForTests>
<baseClassMappings>
<baseClassMapping>
<contractPackageRegex>.*com.*</contractPackageRegex>
<baseClassFQN>com.example.TestBase</baseClassFQN>
</baseClassMapping>
</baseClassMappings>
</configuration>
</plugin>
Let’s assume that you have contracts under
- src/test/resources/contract/com/
- src/test/resources/contract/foo/
By providing the baseClassForTests
we have a fallback in case mapping didn’t succeed (you could also provide
the packageWithBaseClasses
as fallback). That way the tests generated from src/test/resources/contract/com/
contracts
will be extending the com.example.ComBase
whereas the rest of tests will extend com.example.FooBase
.
Invoking generated tests
Spring Cloud Contract Maven Plugin generates verification code into directory /generated-test-sources/contractVerifier
and attach this directory to testCompile
goal.
For Groovy Spock code use:
<plugin>
<groupId>org.codehaus.gmavenplus</groupId>
<artifactId>gmavenplus-plugin</artifactId>
<version>1.5</version>
<executions>
<execution>
<goals>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
<configuration>
<testSources>
<testSource>
<directory>${project.basedir}/src/test/groovy</directory>
<includes>
<include>**/*.groovy</include>
</includes>
</testSource>
<testSource>
<directory>${project.build.directory}/generated-test-sources/contractVerifier</directory>
<includes>
<include>**/*.groovy</include>
</includes>
</testSource>
</testSources>
</configuration>
</plugin>
To ensure that provider side is complaint with defined contracts, you need to invoke mvn generateTest test
FAQ with Maven Plugin
Maven Plugin and STS
In case you see the following exception while using STS
when you click on the marker you should see sth like this
plugin:1.1.0.M1:convert:default-convert:process-test-resources) org.apache.maven.plugin.PluginExecutionException: Execution default-convert of goal org.springframework.cloud:spring-
cloud-contract-maven-plugin:1.1.0.M1:convert failed. at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:145) at
org.eclipse.m2e.core.internal.embedder.MavenImpl.execute(MavenImpl.java:331) at org.eclipse.m2e.core.internal.embedder.MavenImpl$11.call(MavenImpl.java:1362) at
...
org.eclipse.core.internal.jobs.Worker.run(Worker.java:55) Caused by: java.lang.NullPointerException at
org.eclipse.m2e.core.internal.builder.plexusbuildapi.EclipseIncrementalBuildContext.hasDelta(EclipseIncrementalBuildContext.java:53) at
org.sonatype.plexus.build.incremental.ThreadBuildContext.hasDelta(ThreadBuildContext.java:59) at
In order to fix this issue just provide the following section in your pom.xml
<build>
<pluginManagement>
<plugins>
<!--This plugin's configuration is used to store Eclipse m2e settings
only. It has no influence on the Maven build itself. -->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<versionRange>[1.0,)</versionRange>
<goals>
<goal>convert</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
Spring Cloud Contract Verifier on consumer side
You can actually use the Spring Cloud Contract Verifier also for the consumer side!
You can use the plugin so that it only converts the contracts and generates the stubs.
To achieve that you need to configure Spring Cloud Contract Verifier plugin in exactly
the same way as in case of provider. You need to copy contracts stored in
src/test/resources/contracts
and generate WireMock json stubs using:
mvn generateStubs
command. By default generated WireMock mapping is
stored in directory target/mappings
. Your project should create from
this generated mappings additional artifact with classifier stubs
for
easy deploy to maven repository.
Sample configuration:
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${verifier-plugin.version}</version>
<executions>
<execution>
<goals>
<goal>convert</goal>
<goal>generateStubs</goal>
</goals>
</execution>
</executions>
</plugin>
When present, json stubs can be used in consumer automated tests.
@RunWith(SpringTestRunner.class)
@SpringBootTest
@AutoConfigureStubRunner
public class LoanApplicationServiceTests {
@Autowired
LoanApplicationService service;
@Test
public void shouldSuccessfullyApplyForLoan() {
//given:
LoanApplication application =
new LoanApplication(new Client("12345678901"), 123.123);
//when:
LoanApplicationResult loanApplication = service.loanApplication(application);
// then:
assertThat(loanApplication.loanApplicationStatus).isEqualTo(LoanApplicationStatus.LOAN_APPLIED);
assertThat(loanApplication.rejectionReason).isNull();
}
}
Underneath LoanApplication
makes a call to the FraudDetection
service. This request is handled by
a WireMock server configured using stubs generated by Spring Cloud Contract Verifier.
Scenarios
It’s possible to handle scenarios with Spring Cloud Contract Verifier. All you need to do is to stick to proper naming convention while creating your contracts. The convention requires to include order number followed by the underscore.
my_contracts_dir\
scenario1\
1_login.groovy
2_showCart.groovy
3_logout.groovy
Such tree will cause Spring Cloud Contract Verifier generating WireMock’s scenario with name scenario1
and three steps:
-
login marked as
Started
pointing to: -
showCart marked as
Step1
pointing to: -
logout marked as
Step2
which will close the scenario.
More details about WireMock scenarios can be found under http://wiremock.org/stateful-behaviour.html
Spring Cloud Contract Verifier will also generate tests with guaranteed order of execution.
Stubs and transitive dependencies
The Maven and Gradle plugin that we’re created are adding the tasks that create the stubs jar for you. What can be problematic is that when reusing the stubs you can by mistake import all of that stub dependencies! When building a Maven artifact even though you have a couple of different jars, all of them share one pom:
├── github-webhook-0.0.1.BUILD-20160903.075506-1-stubs.jar
├── github-webhook-0.0.1.BUILD-20160903.075506-1-stubs.jar.sha1
├── github-webhook-0.0.1.BUILD-20160903.075655-2-stubs.jar
├── github-webhook-0.0.1.BUILD-20160903.075655-2-stubs.jar.sha1
├── github-webhook-0.0.1.BUILD-SNAPSHOT.jar
├── github-webhook-0.0.1.BUILD-SNAPSHOT.pom
├── github-webhook-0.0.1.BUILD-SNAPSHOT-stubs.jar
├── ...
└── ...
There are three possibilities of working with those dependencies so as not to have any issues with transitive dependencies.
Mark all application dependencies as optional
If in the github-webhook
application we would mark all of our dependencies as optional, when you include the
github-webhook
stubs in another application (or when that dependency gets downloaded by Stub Runner) then, since
all of the depenencies are optional, they will not get downloaded.
Create a separate artifactid for stubs
If you create a separate artifactid then you can set it up in whatever way you wish. For example by having no dependencies at all.
Exclude dependencies on the consumer side
As a consumer, if you add the stub dependency to your classpath you can explicitly exclude the unwanted dependencies.
Spring Cloud Contract Verifier Messaging
Spring Cloud Contract Verifier allows you to verify your application that uses messaging as means of communication. All of our integrations are working with Spring but you can also create one yourself and use it.
Integrations
You can use one of the four integration configurations:
-
Apache Camel
-
Spring Integration
-
Spring Cloud Stream
-
Spring AMQP
Since we’re using Spring Boot then if you have added one of the aforementioned libraries to the classpath then automatically all the messaging configuration will be set up.
Important
|
Remember to put @AutoConfigureMessageVerifier on the base class of your
generated tests. Otherwise messaging part of Spring Cloud Contract Verifier will not work.
|
Important
|
If you want to use Spring Cloud Stream remember to add a
org.springframework.cloud:spring-cloud-stream-test-support dependency.
|
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream-test-support</artifactId>
<scope>test</scope>
</dependency>
testCompile "org.springframework.cloud:spring-cloud-stream-test-support"
Manual Integration Testing
The main interface used by the tests is the org.springframework.cloud.contract.verifier.messaging.MessageVerifier
.
It defines how to send and receive messages. You can create your own implementation to achieve the
same goal.
In the a test you can inject a ContractVerifierMessageExchange
to send and receive messages that follow the contract.
Then add @AutoConfigureMessageVerifier
to your test, e.g.
@RunWith(SpringTestRunner.class)
@SpringBootTest
@AutoConfigureMessageVerifier
public static class MessagingContractTests {
@Autowired
private MessageVerifier verifier;
...
}
Note
|
If your tests require stubs as well, then
@AutoConfigureStubRunner includes the messaging configuration, so
you only need the one annotation.
|
Publisher side test generation
Having the input
or outputMessage
sections in your DSL will result in creation of tests on the publisher’s side. By default
JUnit tests will be created, however there is also a possibility to create Spock tests.
There are 3 main scenarios that we should take into consideration:
-
Scenario 1: there is no input message that produces an output one. The output message is triggered by a component inside the application (e.g. scheduler)
-
Scenario 2: the input message triggers an output message
-
Scenario 3: the input message is consumed and there is no output message
Important
|
The destination passed to messageFrom or sentTo can have different meanings for different
messaging implementations. For Stream and Integration it’s first resolved as a destination of a channel, and then if
there is no such destination it’s resolved as a channel name. For Camel that’s a certain component (e.x. jms ).
|
Example for Camel:
Scenario 1 (no input message)
For the given contract:
def contractDsl = Contract.make {
label 'some_label'
input {
triggeredBy('bookReturnedTriggered()')
}
outputMessage {
sentTo('activemq:output')
body('''{ "bookName" : "foo" }''')
headers {
header('BOOK-NAME', 'foo')
messagingContentType(applicationJson())
}
}
}
The following JUnit test will be created:
'''
// when:
bookReturnedTriggered();
// then:
ContractVerifierMessage response = contractVerifierMessaging.receive("activemq:output");
assertThat(response).isNotNull();
assertThat(response.getHeader("BOOK-NAME")).isNotNull();
assertThat(response.getHeader("BOOK-NAME").toString()).isEqualTo("foo");
assertThat(response.getHeader("contentType")).isNotNull();
assertThat(response.getHeader("contentType").toString()).isEqualTo("application/json");
// and:
DocumentContext parsedJson = JsonPath.parse(contractVerifierObjectMapper.writeValueAsString(response.getPayload()));
assertThatJson(parsedJson).field("bookName").isEqualTo("foo");
'''
And the following Spock test would be created:
'''
when:
bookReturnedTriggered()
then:
ContractVerifierMessage response = contractVerifierMessaging.receive('activemq:output')
assert response != null
response.getHeader('BOOK-NAME')?.toString() == 'foo'
response.getHeader('contentType')?.toString() == 'application/json'
and:
DocumentContext parsedJson = JsonPath.parse(contractVerifierObjectMapper.writeValueAsString(response.payload))
assertThatJson(parsedJson).field("bookName").isEqualTo("foo")
'''
Scenario 2 (output triggered by input)
For the given contract:
def contractDsl = Contract.make {
label 'some_label'
input {
messageFrom('jms:input')
messageBody([
bookName: 'foo'
])
messageHeaders {
header('sample', 'header')
}
}
outputMessage {
sentTo('jms:output')
body([
bookName: 'foo'
])
headers {
header('BOOK-NAME', 'foo')
}
}
}
The following JUnit test will be created:
'''
// given:
ContractVerifierMessage inputMessage = contractVerifierMessaging.create(
"{\\"bookName\\":\\"foo\\"}"
, headers()
.header("sample", "header"));
// when:
contractVerifierMessaging.send(inputMessage, "jms:input");
// then:
ContractVerifierMessage response = contractVerifierMessaging.receive("jms:output");
assertThat(response).isNotNull();
assertThat(response.getHeader("BOOK-NAME")).isNotNull();
assertThat(response.getHeader("BOOK-NAME").toString()).isEqualTo("foo");
// and:
DocumentContext parsedJson = JsonPath.parse(contractVerifierObjectMapper.writeValueAsString(response.getPayload()));
assertThatJson(parsedJson).field("bookName").isEqualTo("foo");
'''
And the following Spock test would be created:
"""\
given:
ContractVerifierMessage inputMessage = contractVerifierMessaging.create(
'''{"bookName":"foo"}''',
['sample': 'header']
)
when:
contractVerifierMessaging.send(inputMessage, 'jms:input')
then:
ContractVerifierMessage response = contractVerifierMessaging.receive('jms:output')
assert response !- null
response.getHeader('BOOK-NAME')?.toString() == 'foo'
and:
DocumentContext parsedJson = JsonPath.parse(contractVerifierObjectMapper.writeValueAsString(response.payload))
assertThatJson(parsedJson).field("bookName").isEqualTo("foo")
"""
Scenario 3 (no output message)
For the given contract:
def contractDsl = Contract.make {
label 'some_label'
input {
messageFrom('jms:delete')
messageBody([
bookName: 'foo'
])
messageHeaders {
header('sample', 'header')
}
assertThat('bookWasDeleted()')
}
}
The following JUnit test will be created:
'''
// given:
ContractVerifierMessage inputMessage = contractVerifierMessaging.create(
"{\\"bookName\\":\\"foo\\"}"
, headers()
.header("sample", "header"));
// when:
contractVerifierMessaging.send(inputMessage, "jms:delete");
// then:
bookWasDeleted();
'''
And the following Spock test would be created:
'''
given:
ContractVerifierMessage inputMessage = contractVerifierMessaging.create(
\'\'\'{"bookName":"foo"}\'\'\',
['sample': 'header']
)
when:
contractVerifierMessaging.send(inputMessage, 'jms:delete')
then:
noExceptionThrown()
bookWasDeleted()
'''
Consumer Stub Side generation
Unlike the HTTP part - in Messaging we need to publish the Groovy DSL inside the JAR with a stub. Then it’s parsed on the consumer side and proper stubbed routes are created.
For more information please consult the Stub Runner Messaging sections.
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-stream-rabbit</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-contract-stub-runner</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream-test-support</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.BUILD-SNAPSHOT</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
ext {
contractsDir = file("mappings")
stubsOutputDirRoot = file("${project.buildDir}/production/${project.name}-stubs/")
}
// Automatically added by plugin:
// copyContracts - copies contracts to the output folder from which JAR will be created
// verifierStubsJar - JAR with a provided stub suffix
// the presented publication is also added by the plugin but you can modify it as you wish
publishing {
publications {
stubs(MavenPublication) {
artifactId "${project.name}-stubs"
artifact verifierStubsJar
}
}
}
Spring Cloud Contract Stub Runner
One of the issues that you could have encountered while using Spring Cloud Contract Verifier was to pass the generated WireMock JSON stubs from the server side to the client side (or various clients). The same takes place in terms of client side generation for messaging.
Copying the JSON files / setting the client side for messaging manually is out of the question.
That’s why we’ll introduce Spring Cloud Contract Stub Runner that can download and run the stubs automatically for you.
Snapshot versions
Add the additional snapshot repository to your build.gradle to use snapshot versions which are automatically uploaded after every successful build:
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/release</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
buildscript {
repositories {
mavenCentral()
mavenLocal()
maven { url "http://repo.spring.io/snapshot" }
maven { url "http://repo.spring.io/milestone" }
maven { url "http://repo.spring.io/release" }
}
Publishing stubs as JARs
The easiest approach would be to centralize the way stubs are kept. For example you can keep them as JARs in a Maven repository.
Tip
|
For both Maven and Gradle the setup comes out of the box. But you can customize it if you want to. |
<!-- First disable the default jar setup in the properties section-->
<!-- we don't want the verifier to do a jar for us -->
<spring.cloud.contract.verifier.skip>true</spring.cloud.contract.verifier.skip>
<!-- Next add the assembly plugin to your build -->
<!-- we want the assembly plugin to generate the JAR -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<id>stub</id>
<phase>prepare-package</phase>
<goals>
<goal>single</goal>
</goals>
<inherited>false</inherited>
<configuration>
<attach>true</attach>
<descriptor>${basedir}/src/assembly/stub.xml</descriptor>
</configuration>
</execution>
</executions>
</plugin>
<!-- Finally setup your assembly. Below you can find the contents of src/main/assembly/stub.xml -->
<assembly
xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
<id>stubs</id>
<formats>
<format>jar</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<fileSets>
<fileSet>
<directory>src/main/java</directory>
<outputDirectory>/</outputDirectory>
<includes>
<include>**com/example/model/*.*</include>
</includes>
</fileSet>
<fileSet>
<directory>${project.build.directory}/classes</directory>
<outputDirectory>/</outputDirectory>
<includes>
<include>**com/example/model/*.*</include>
</includes>
</fileSet>
<fileSet>
<directory>${project.build.directory}/snippets/stubs</directory>
<outputDirectory>META-INF/${project.groupId}/${project.artifactId}/${project.version}/mappings</outputDirectory>
<includes>
<include>**/*</include>
</includes>
</fileSet>
<fileSet>
<directory>${basedir}/src/test/resources/contracts</directory>
<outputDirectory>META-INF/${project.groupId}/${project.artifactId}/${project.version}/contracts</outputDirectory>
<includes>
<include>**/*.groovy</include>
</includes>
</fileSet>
</fileSets>
</assembly>
ext {
contractsDir = file("mappings")
stubsOutputDirRoot = file("${project.buildDir}/production/${project.name}-stubs/")
}
// Automatically added by plugin:
// copyContracts - copies contracts to the output folder from which JAR will be created
// verifierStubsJar - JAR with a provided stub suffix
// the presented publication is also added by the plugin but you can modify it as you wish
publishing {
publications {
stubs(MavenPublication) {
artifactId "${project.name}-stubs"
artifact verifierStubsJar
}
}
}
Stub Runner Core
Runs stubs for service collaborators. Treating stubs as contracts of services allows to use stub-runner as an implementation of Consumer Driven Contracts.
Stub Runner allows you to automatically download the stubs of the provided dependencies (or pick those from the classpath), start WireMock servers for them and feed them with proper stub definitions. For messaging, special stub routes are defined.
Retrieving stubs
You can pick the following options of acquiring stubs
-
Aether based solution that downloads JARs with stubs from Artifactory / Nexus
-
Classpath scanning solution that searches classpath via pattern to retrieve stubs
-
Write your own implementation of the
org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder
for full customization
The latter example is described in the Custom Stub Runner section.
Stub downloading
If you provide the stubrunner.repositoryRoot
or stubrunner.workOffline
flag will be set
to true
then Stub Runner will connect to the given server and download the required jars.
It will then unpack the JAR to a temporary folder and reference those files in further
contract processing.
Example:
@AutoConfigureStubRunner(repositoryRoot="http://foo.bar", ids = "com.example:beer-api-producer:+:stubs:8095")
Classpath scanning
If you DON’T provide the stubrunner.repositoryRoot
and stubrunner.workOffline
flag will
be set to false
(that’s the default) then classpath will get scanned. Let’s look at the
following example:
@AutoConfigureStubRunner(ids = {
"com.example:beer-api-producer:+:stubs:8095",
"com.example.foo:bar:1.0.0:superstubs:8096"
})
If you’ve added the dependencies to your classpath
<dependency>
<groupId>com.example</groupId>
<artifactId>beer-api-producer-restdocs</artifactId>
<classifier>stubs</classifier>
<version>0.0.1-SNAPSHOT</version>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>*</groupId>
<artifactId>*</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.example.foo</groupId>
<artifactId>bar</artifactId>
<classifier>superstubs</classifier>
<version>1.0.0</version>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>*</groupId>
<artifactId>*</artifactId>
</exclusion>
</exclusions>
</dependency>
testCompile("com.example:beer-api-producer-restdocs:0.0.1-SNAPSHOT:stubs") {
transitive = false
}
testCompile("com.example.foo:bar:1.0.0:superstubs") {
transitive = false
}
Then the following locations on your classpath will get scanned. For com.example:beer-api-producer-restdocs
-
/META-INF/com.example/beer-api-producer-restdocs/*/.*
-
/contracts/com.example/beer-api-producer-restdocs/*/.*
-
/mappings/com.example/beer-api-producer-restdocs/*/.*
and com.example.foo:bar
-
/META-INF/com.example.foo/bar/*/.*
-
/contracts/com.example.foo/bar/*/.*
-
/mappings/com.example.foo/bar/*/.*
Tip
|
As you can see you have to explicitly provide the group and artifact ids when packaging the producer stubs. |
The producer would setup the contracts like this:
└── src
└── test
└── resources
└── contracts
└── com.example
└── beer-api-producer-restdocs
└── nested
└── contract3.groovy
To achieve proper stub packaging.
Or using the Maven assembly
plugin or
Gradle Jar task you have to create the following
structure in your stubs jar.
└── META-INF
└── com.example
└── beer-api-producer-restdocs
└── 2.0.0
├── contracts
│ └── nested
│ └── contract2.groovy
└── mappings
└── mapping.json
By maintaining this structure classpath gets scanned and you can profit from the messaging / HTTP stubs without the need to download artifacts.
Running stubs
Limitations
Important
|
There might be a problem with StubRunner shutting down ports between tests. You might
have a situation in which you get port conflicts. As long as you use the same context across tests
everything works fine. But when the context are different (e.g. different stubs or different profiles)
then you have to either use @DirtiesContext to shut down the stub servers, or else run them on
different ports per test.
|
Running using main app
You can set the following options to the main class:
-c, --classifier Suffix for the jar containing stubs (e.
g. 'stubs' if the stub jar would
have a 'stubs' classifier for stubs:
foobar-stubs ). Defaults to 'stubs'
(default: stubs)
--maxPort, --maxp <Integer> Maximum port value to be assigned to
the WireMock instance. Defaults to
15000 (default: 15000)
--minPort, --minp <Integer> Minimum port value to be assigned to
the WireMock instance. Defaults to
10000 (default: 10000)
-p, --password Password to user when connecting to
repository
--phost, --proxyHost Proxy host to use for repository
requests
--pport, --proxyPort [Integer] Proxy port to use for repository
requests
-r, --root Location of a Jar containing server
where you keep your stubs (e.g. http:
//nexus.
net/content/repositories/repository)
-s, --stubs Comma separated list of Ivy
representation of jars with stubs.
Eg. groupid:artifactid1,groupid2:
artifactid2:classifier
-u, --username Username to user when connecting to
repository
--wo, --workOffline Switch to work offline. Defaults to
'false'
HTTP Stubs
Stubs are defined in JSON documents, whose syntax is defined in WireMock documentation
Example:
{
"request": {
"method": "GET",
"url": "/ping"
},
"response": {
"status": 200,
"body": "pong",
"headers": {
"Content-Type": "text/plain"
}
}
}
Viewing registered mappings
Every stubbed collaborator exposes list of defined mappings under __/admin/
endpoint.
Messaging Stubs
Depending on the provided Stub Runner dependency and the DSL the messaging routes are automatically set up.
Stub Runner JUnit Rule
Stub Runner comes with a JUnit rule thanks to which you can very easily download and run stubs for given group and artifact id:
@ClassRule public static StubRunnerRule rule = new StubRunnerRule()
.repoRoot(repoRoot())
.downloadStub("org.springframework.cloud.contract.verifier.stubs", "loanIssuance")
.downloadStub("org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer");
After that rule gets executed Stub Runner connects to your Maven repository and for the given list of dependencies tries to:
-
download them
-
cache them locally
-
unzip them to a temporary folder
-
start a WireMock server for each Maven dependency on a random port from the provided range of ports / provided port
-
feed the WireMock server with all JSON files that are valid WireMock definitions
-
can also send messages (remember to pass an implementation of
MessageVerifier
interface)
Stub Runner uses Eclipse Aether mechanism to download the Maven dependencies. Check their docs for more information.
Since the StubRunnerRule
implements the StubFinder
it allows you to find the started stubs:
package org.springframework.cloud.contract.stubrunner;
import java.net.URL;
import java.util.Collection;
import java.util.Map;
import org.springframework.cloud.contract.spec.Contract;
public interface StubFinder extends StubTrigger {
/**
* For the given groupId and artifactId tries to find the matching
* URL of the running stub.
*
* @param groupId - might be null. In that case a search only via artifactId takes place
* @return URL of a running stub or throws exception if not found
*/
URL findStubUrl(String groupId, String artifactId) throws StubNotFoundException;
/**
* For the given Ivy notation {@code [groupId]:artifactId:[version]:[classifier]} tries to
* find the matching URL of the running stub. You can also pass only {@code artifactId}.
*
* @param ivyNotation - Ivy representation of the Maven artifact
* @return URL of a running stub or throws exception if not found
*/
URL findStubUrl(String ivyNotation) throws StubNotFoundException;
/**
* Returns all running stubs
*/
RunningStubs findAllRunningStubs();
/**
* Returns the list of Contracts
*/
Map<StubConfiguration, Collection<Contract>> getContracts();
}
Example of usage in Spock tests:
@ClassRule @Shared StubRunnerRule rule = new StubRunnerRule()
.repoRoot(StubRunnerRuleSpec.getResource("/m2repo/repository").toURI().toString())
.downloadStub("org.springframework.cloud.contract.verifier.stubs", "loanIssuance")
.downloadStub("org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer")
def 'should start WireMock servers'() {
expect: 'WireMocks are running'
rule.findStubUrl('org.springframework.cloud.contract.verifier.stubs', 'loanIssuance') != null
rule.findStubUrl('loanIssuance') != null
rule.findStubUrl('loanIssuance') == rule.findStubUrl('org.springframework.cloud.contract.verifier.stubs', 'loanIssuance')
rule.findStubUrl('org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer') != null
and:
rule.findAllRunningStubs().isPresent('loanIssuance')
rule.findAllRunningStubs().isPresent('org.springframework.cloud.contract.verifier.stubs', 'fraudDetectionServer')
rule.findAllRunningStubs().isPresent('org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer')
and: 'Stubs were registered'
"${rule.findStubUrl('loanIssuance').toString()}/name".toURL().text == 'loanIssuance'
"${rule.findStubUrl('fraudDetectionServer').toString()}/name".toURL().text == 'fraudDetectionServer'
}
Example of usage in JUnit tests:
@Test
public void should_start_wiremock_servers() throws Exception {
// expect: 'WireMocks are running'
then(rule.findStubUrl("org.springframework.cloud.contract.verifier.stubs", "loanIssuance")).isNotNull();
then(rule.findStubUrl("loanIssuance")).isNotNull();
then(rule.findStubUrl("loanIssuance")).isEqualTo(rule.findStubUrl("org.springframework.cloud.contract.verifier.stubs", "loanIssuance"));
then(rule.findStubUrl("org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer")).isNotNull();
// and:
then(rule.findAllRunningStubs().isPresent("loanIssuance")).isTrue();
then(rule.findAllRunningStubs().isPresent("org.springframework.cloud.contract.verifier.stubs", "fraudDetectionServer")).isTrue();
then(rule.findAllRunningStubs().isPresent("org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer")).isTrue();
// and: 'Stubs were registered'
then(httpGet(rule.findStubUrl("loanIssuance").toString() + "/name")).isEqualTo("loanIssuance");
then(httpGet(rule.findStubUrl("fraudDetectionServer").toString() + "/name")).isEqualTo("fraudDetectionServer");
}
Check the Common properties for JUnit and Spring for more information on how to apply global configuration of Stub Runner.
Important
|
To use the JUnit rule together with messaging you have to provide an implementation of the
MessageVerifier interface to the rule builder (e.g. rule.messageVerifier(new MyMessageVerifier()) ).
If you don’t do this then whenever you try to send a message an exception will be thrown.
|
Maven settings
The stub downloader honors Maven settings for a different local repository folder. Authentication details for repositories and profiles are currently not taken into account, so you need to specify it using the properties mentioned above.
Providing fixed ports
You can also run your stubs on fixed ports. You can do it in two different ways. One is to pass it in the properties, and the other via fluent API of JUnit rule.
Fluent API
When using the StubRunnerRule
you can add a stub to download and then pass the port for the last downloaded stub.
@ClassRule public static StubRunnerRule rule = new StubRunnerRule()
.repoRoot(repoRoot())
.downloadStub("org.springframework.cloud.contract.verifier.stubs", "loanIssuance")
.withPort(12345)
.downloadStub("org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer:12346");
You can see that for this example the following test is valid:
then(rule.findStubUrl("loanIssuance")).isEqualTo(URI.create("http://localhost:12345").toURL());
then(rule.findStubUrl("fraudDetectionServer")).isEqualTo(URI.create("http://localhost:12346").toURL());
Stub Runner with Spring
Sets up Spring configuration of the Stub Runner project.
By providing a list of stubs inside your configuration file the Stub Runner automatically downloads and registers in WireMock the selected stubs.
If you want to find the URL of your stubbed dependency you can autowire the StubFinder
interface and use
its methods as presented below:
@ContextConfiguration(classes = Config, loader = SpringBootContextLoader)
@SpringBootTest(properties = [" stubrunner.cloud.enabled=false",
"stubrunner.camel.enabled=false",
'foo=${stubrunner.runningstubs.fraudDetectionServer.port}'])
@AutoConfigureStubRunner
@DirtiesContext
@ActiveProfiles("test")
class StubRunnerConfigurationSpec extends Specification {
@Autowired StubFinder stubFinder
@Autowired Environment environment
@Value('${foo}') Integer foo
@BeforeClass
@AfterClass
void setupProps() {
System.clearProperty("stubrunner.repository.root")
System.clearProperty("stubrunner.classifier")
}
def 'should start WireMock servers'() {
expect: 'WireMocks are running'
stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs', 'loanIssuance') != null
stubFinder.findStubUrl('loanIssuance') != null
stubFinder.findStubUrl('loanIssuance') == stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs', 'loanIssuance')
stubFinder.findStubUrl('loanIssuance') == stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs:loanIssuance')
stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs:loanIssuance:0.0.1-SNAPSHOT') == stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs:loanIssuance:0.0.1-SNAPSHOT:stubs')
stubFinder.findStubUrl('org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer') != null
and:
stubFinder.findAllRunningStubs().isPresent('loanIssuance')
stubFinder.findAllRunningStubs().isPresent('org.springframework.cloud.contract.verifier.stubs', 'fraudDetectionServer')
stubFinder.findAllRunningStubs().isPresent('org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer')
and: 'Stubs were registered'
"${stubFinder.findStubUrl('loanIssuance').toString()}/name".toURL().text == 'loanIssuance'
"${stubFinder.findStubUrl('fraudDetectionServer').toString()}/name".toURL().text == 'fraudDetectionServer'
}
def 'should throw an exception when stub is not found'() {
when:
stubFinder.findStubUrl('nonExistingService')
then:
thrown(StubNotFoundException)
when:
stubFinder.findStubUrl('nonExistingGroupId', 'nonExistingArtifactId')
then:
thrown(StubNotFoundException)
}
def 'should register started servers as environment variables'() {
expect:
environment.getProperty("stubrunner.runningstubs.loanIssuance.port") != null
stubFinder.findAllRunningStubs().getPort("loanIssuance") == (environment.getProperty("stubrunner.runningstubs.loanIssuance.port") as Integer)
and:
environment.getProperty("stubrunner.runningstubs.fraudDetectionServer.port") != null
stubFinder.findAllRunningStubs().getPort("fraudDetectionServer") == (environment.getProperty("stubrunner.runningstubs.fraudDetectionServer.port") as Integer)
}
def 'should be able to interpolate a running stub in the passed test property'() {
given:
int fraudPort = stubFinder.findAllRunningStubs().getPort("fraudDetectionServer")
expect:
fraudPort > 0
environment.getProperty("foo", Integer) == fraudPort
foo == fraudPort
}
@Configuration
@EnableAutoConfiguration
static class Config {}
}
for the following configuration file:
stubrunner:
repositoryRoot: classpath:m2repo/repository/
ids:
- org.springframework.cloud.contract.verifier.stubs:loanIssuance
- org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer
- org.springframework.cloud.contract.verifier.stubs:bootService
cloud:
enabled: false
camel:
enabled: false
spring.cloud:
consul.enabled: false
service-registry.enabled: false
Instead of using the properties you can also use the properties inside the @AutoConfigureStubRunner
.
Below you can find an example of achieving the same result by setting values on the annotation.
@AutoConfigureStubRunner(
ids = ["org.springframework.cloud.contract.verifier.stubs:loanIssuance",
"org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer",
"org.springframework.cloud.contract.verifier.stubs:bootService"],
repositoryRoot = "classpath:m2repo/repository/")
Stub Runner Spring registers environment variables in the following manner
for every registered WireMock server. Example for Stub Runner ids
com.example:foo
, com.example:bar
.
-
stubrunner.runningstubs.foo.port
-
stubrunner.runningstubs.bar.port
Which you can reference in your code.
Stub Runner Spring Cloud
Stub Runner can integrate with Spring Cloud.
For real life examples you can check the
Stubbing Service Discovery
The most important feature of Stub Runner Spring Cloud
is the fact that it’s stubbing
-
DiscoveryClient
-
Ribbon
ServerList
that means that regardless of the fact whether you’re using Zookeeper, Consul, Eureka or anything else, you don’t need that in your tests.
We’re starting WireMock instances of your dependencies and we’re telling your application whenever you’re using Feign
, load balanced RestTemplate
or DiscoveryClient
directly, to call those stubbed servers instead of calling the real Service Discovery tool.
For example this test will pass
def 'should make service discovery work'() {
expect: 'WireMocks are running'
"${stubFinder.findStubUrl('loanIssuance').toString()}/name".toURL().text == 'loanIssuance'
"${stubFinder.findStubUrl('fraudDetectionServer').toString()}/name".toURL().text == 'fraudDetectionServer'
and: 'Stubs can be reached via load service discovery'
restTemplate.getForObject('http://loanIssuance/name', String) == 'loanIssuance'
restTemplate.getForObject('http://someNameThatShouldMapFraudDetectionServer/name', String) == 'fraudDetectionServer'
}
for the following configuration file
spring.cloud:
zookeeper.enabled: false
consul.enabled: false
eureka.client.enabled: false
stubrunner:
camel.enabled: false
idsToServiceIds:
ivyNotation: someValueInsideYourCode
fraudDetectionServer: someNameThatShouldMapFraudDetectionServer
Test profiles and service discovery
In your integration tests you typically don’t want to call neither a discovery service (e.g. Eureka) or Config Server. That’s why you create an additional test configuration in which you want to disable these features.
Due to certain limitations of spring-cloud-commons
to achieve this you have disable these properties
via a static block like presented below (example for Eureka)
//Hack to work around https://github.com/spring-cloud/spring-cloud-commons/issues/156
static {
System.setProperty("eureka.client.enabled", "false");
System.setProperty("spring.cloud.config.failFast", "false");
}
Additional Configuration
You can match the artifactId of the stub with the name of your app by using the stubrunner.idsToServiceIds:
map.
You can disable Stub Runner Ribbon support by providing: stubrunner.cloud.ribbon.enabled
equal to false
You can disable Stub Runner support by providing: stubrunner.cloud.enabled
equal to false
Tip
|
By default all service discovery will be stubbed. That means that regardless of the fact if you have
an existing DiscoveryClient its results will be ignored. However, if you want to reuse it, just set
stubrunner.cloud.delegate.enabled to true and then your existing DiscoveryClient results will be
merged with the stubbed ones.
|
Stub Runner Boot Application
Spring Cloud Contract Verifier Stub Runner Boot is a Spring Boot application that exposes REST endpoints to trigger the messaging labels and to access started WireMock servers.
One of the use-cases is to run some smoke (end to end) tests on a deployed application. You can read more about this in the "Microservice Deployment" article at Too Much Coding blog.
How to use it?
Just add the
compile "org.springframework.cloud:spring-cloud-starter-stub-runner"
Annotate a class with @EnableStubRunnerServer
, build a fat-jar and you’re ready to go!
For the properties check the Stub Runner Spring section.
Endpoints
HTTP
-
GET
/stubs
- returns a list of all running stubs inivy:integer
notation -
GET
/stubs/{ivy}
- returns a port for the givenivy
notation (when calling the endpointivy
can also beartifactId
only)
Messaging
For Messaging
-
GET
/triggers
- returns a list of all running labels inivy : [ label1, label2 …]
notation -
POST
/triggers/{label}
- executes a trigger withlabel
-
POST
/triggers/{ivy}/{label}
- executes a trigger withlabel
for the givenivy
notation (when calling the endpointivy
can also beartifactId
only)
Example
@ContextConfiguration(classes = StubRunnerBoot, loader = SpringBootContextLoader)
@SpringBootTest(properties = "spring.cloud.zookeeper.enabled=false")
@ActiveProfiles("test")
class StubRunnerBootSpec extends Specification {
@Autowired StubRunning stubRunning
def setup() {
RestAssuredMockMvc.standaloneSetup(new HttpStubsController(stubRunning),
new TriggerController(stubRunning))
}
def 'should return a list of running stub servers in "full ivy:port" notation'() {
when:
String response = RestAssuredMockMvc.get('/stubs').body.asString()
then:
def root = new JsonSlurper().parseText(response)
root.'org.springframework.cloud.contract.verifier.stubs:bootService:0.0.1-SNAPSHOT:stubs' instanceof Integer
}
def 'should return a port on which a [#stubId] stub is running'() {
when:
def response = RestAssuredMockMvc.get("/stubs/${stubId}")
then:
response.statusCode == 200
response.body.as(Integer) > 0
where:
stubId << ['org.springframework.cloud.contract.verifier.stubs:bootService:+:stubs',
'org.springframework.cloud.contract.verifier.stubs:bootService:0.0.1-SNAPSHOT:stubs',
'org.springframework.cloud.contract.verifier.stubs:bootService:+',
'org.springframework.cloud.contract.verifier.stubs:bootService',
'bootService']
}
def 'should return 404 when missing stub was called'() {
when:
def response = RestAssuredMockMvc.get("/stubs/a:b:c:d")
then:
response.statusCode == 404
}
def 'should return a list of messaging labels that can be triggered when version and classifier are passed'() {
when:
String response = RestAssuredMockMvc.get('/triggers').body.asString()
then:
def root = new JsonSlurper().parseText(response)
root.'org.springframework.cloud.contract.verifier.stubs:bootService:0.0.1-SNAPSHOT:stubs'?.containsAll(["delete_book","return_book_1","return_book_2"])
}
def 'should trigger a messaging label'() {
given:
StubRunning stubRunning = Mock()
RestAssuredMockMvc.standaloneSetup(new HttpStubsController(stubRunning), new TriggerController(stubRunning))
when:
def response = RestAssuredMockMvc.post("/triggers/delete_book")
then:
response.statusCode == 200
and:
1 * stubRunning.trigger('delete_book')
}
def 'should trigger a messaging label for a stub with [#stubId] ivy notation'() {
given:
StubRunning stubRunning = Mock()
RestAssuredMockMvc.standaloneSetup(new HttpStubsController(stubRunning), new TriggerController(stubRunning))
when:
def response = RestAssuredMockMvc.post("/triggers/$stubId/delete_book")
then:
response.statusCode == 200
and:
1 * stubRunning.trigger(stubId, 'delete_book')
where:
stubId << ['org.springframework.cloud.contract.verifier.stubs:bootService:stubs', 'org.springframework.cloud.contract.verifier.stubs:bootService', 'bootService']
}
def 'should throw exception when trigger is missing'() {
when:
RestAssuredMockMvc.post("/triggers/missing_label")
then:
Exception e = thrown(Exception)
e.message.contains("Exception occurred while trying to return [missing_label] label.")
e.message.contains("Available labels are")
e.message.contains("org.springframework.cloud.contract.verifier.stubs:loanIssuance:0.0.1-SNAPSHOT:stubs=[]")
e.message.contains("org.springframework.cloud.contract.verifier.stubs:bootService:0.0.1-SNAPSHOT:stubs=")
}
}
Stub Runner Boot with Service Discovery
One of the possibilities of using Stub Runner Boot is to use it as a feed of stubs for "smoke-tests". What does it mean? Let’s assume that you don’t want to deploy 50 microservice to a test environment in order to check if your application is working fine. You’ve already executed a suite of tests during the build process but you would also like to ensure that the packaging of your application is fine. What you can do is to deploy your application to an environment, start it and run a couple of tests on it to see if it’s working fine. We can call those tests smoke-tests since their idea is to check only a handful of testing scenarios.
The problem with this approach is such that if you’re doing microservices most likely you’re using a service discovery tool. Stub Runner Boot allows you to solve this issue by starting the required stubs and register them in a service discovery tool. Let’s take a look at an example of such a setup with Eureka. Let’s assume that Eureka was already running.
@SpringBootApplication
@EnableStubRunnerServer
@EnableEurekaClient
@AutoConfigureStubRunner
public class StubRunnerBootEurekaExample {
public static void main(String[] args) {
SpringApplication.run(StubRunnerBootEurekaExample.class, args);
}
}
As you can see we want to start a Stub Runner Boot server @EnableStubRunnerServer
, enable Eureka client @EnableEurekaClient
and we want to have the stub runner feature turned on @AutoConfigureStubRunner
.
Now let’s assume that we want to start this application so that the stubs get automatically registered.
We can do it by running the app java -jar ${SYSTEM_PROPS} stub-runner-boot-eureka-example.jar
where
${SYSTEM_PROPS}
would contain the following list of properties
-Dstubrunner.repositoryRoot=http://repo.spring.io/snapshots (1)
-Dstubrunner.cloud.stubbed.discovery.enabled=false (2)
-Dstubrunner.ids=org.springframework.cloud.contract.verifier.stubs:loanIssuance,org.springframework.cloud.contract.verifier.stubs:fraudDetectionServer,org.springframework.cloud.contract.verifier.stubs:bootService (3)
-Dstubrunner.idsToServiceIds.fraudDetectionServer=someNameThatShouldMapFraudDetectionServer (4)
(1) - we tell Stub Runner where all the stubs reside
(2) - we don't want the default behaviour where the discovery service is stubbed. That's why the stub registration will be picked
(3) - we provide a list of stubs to download
(4) - we provide a list of artifactId to serviceId mapping
That way your deployed application can send requests to started WireMock servers via the service
discovery. Most likely points 1-3 could be set by default in application.yml
cause they are not
likely to change. That way you can provide only the list of stubs to download whenever you start
the Stub Runner Boot.
Stubs Per Consumer
There are cases in which 2 consumers of the same endpoint want to have 2 different responses.
Tip
|
This approach also allows you to immediately know which consumer is using which part of your API. You can remove part of a response that your API produces and you can see which of your autogenerated tests fails. If none fails then you can safely delete that part of the response cause nobody is using it. |
Let’s look at the following example for contract defined for the producer called producer
.
There are 2 consumers: foo-consumer
and bar-consumer
.
Consumer foo-service
request {
url '/foo'
method GET()
}
response {
status 200
body(
foo: "foo"
}
}
Consumer bar-service
request {
url '/foo'
method GET()
}
response {
status 200
body(
bar: "bar"
}
}
You can’t produce for the same request 2 different responses. That’s why you can properly package the
contracts and then profit from the stubsPerConsumer
feature.
On the producer side the consumers can have a folder that contains contracts related only to them.
By setting the stubrunner.stubs-per-consumer
flag to true
we no longer register all stubs but only those that
correspond to the consumer application’s name. In other words we’ll scan the path of every stub and
if it contains the subfolder with name of the consumer in the path only then will it get registered.
On the foo
producer side the contracts would look like this
.
└── contracts
├── bar-consumer
│ ├── bookReturnedForBar.groovy
│ └── shouldCallBar.groovy
└── foo-consumer
├── bookReturnedForFoo.groovy
└── shouldCallFoo.groovy
Being the bar-consumer
consumer you can either set the spring.application.name
or the stubrunner.consumer-name
to bar-consumer
Or set the test as follows:
@ContextConfiguration(classes = Config, loader = SpringBootContextLoader)
@SpringBootTest(properties = ["spring.application.name=bar-consumer"])
@AutoConfigureStubRunner(ids = "org.springframework.cloud.contract.verifier.stubs:producerWithMultipleConsumers",
repositoryRoot = "classpath:m2repo/repository/",
stubsPerConsumer = true)
@DirtiesContext
class StubRunnerStubsPerConsumerSpec extends Specification {
...
}
Then only the stubs registered under a path that contains the bar-consumer
in its name (i.e. those from the
src/test/resources/contracts/bar-consumer/some/contracts/…
folder) will be allowed to be referenced.
Or set the consumer name explicitly
@ContextConfiguration(classes = Config, loader = SpringBootContextLoader)
@SpringBootTest
@AutoConfigureStubRunner(ids = "org.springframework.cloud.contract.verifier.stubs:producerWithMultipleConsumers",
repositoryRoot = "classpath:m2repo/repository/",
consumerName = "foo-consumer",
stubsPerConsumer = true)
@DirtiesContext
class StubRunnerStubsPerConsumerWithConsumerNameSpec extends Specification {
...
}
Then only the stubs registered under a path that contains the foo-consumer
in its name (i.e. those from the
src/test/resources/contracts/foo-consumer/some/contracts/…
folder) will be allowed to be referenced.
You can check out issue 224 for more information about the reasons behind this change.
Common
Common properties for JUnit and Spring
Some of the properties that are repetitive can be set using system properties or configuration properties (for Spring). Here are their names with their default values:
Property name | Default value | Description |
---|---|---|
stubrunner.minPort |
10000 |
Minimal value of a port for a started WireMock with stubs |
stubrunner.maxPort |
15000 |
Minimal value of a port for a started WireMock with stubs |
stubrunner.repositoryRoot |
Maven repo url. If blank then will call the local maven repo |
|
stubrunner.classifier |
stubs |
Default classifier for the stub artifacts |
stubrunner.workOffline |
false |
If true then will not contact any remote repositories to download stubs |
stubrunner.ids |
Array of Ivy notation stubs to download |
|
stubrunner.username |
Optional username to access the tool that stores the JARs with stubs |
|
stubrunner.password |
Optional password to access the tool that stores the JARs with stubs |
|
stubrunner.stubsPerConsumer |
false |
Set to |
stubrunner.consumerName |
If you want to use stubs per consumer and want to override the consumer name just change this value |
Stub runner stubs ids
You can provide the stubs to download via the stubrunner.ids
system property. They follow the following pattern:
groupId:artifactId:version:classifier:port
version
, classifier
and port
are optional.
-
If you don’t provide the
port
then a random one will be picked -
If you don’t provide the
classifier
then the default one will be taken. (NOTE that you can pass an empty classifier like thisgroupId:artifactId:version:
) -
If you don’t provide the
version
then the+
will be passed and the latest one will be downloaded
Where port
means the port of the WireMock server.
Important
|
Starting from version 1.0.4 as a version you can provide a range of versions that you would like the Stub Runner to take into consideration. You can read more about the Aether versioning ranges here. |
Taken from Aether Docs:
This scheme accepts versions of any form, interpreting a version as a sequence of numeric and alphabetic segments. The characters '-', '_', and '.' as well as the mere transitions from digit to letter and vice versa delimit the version segments. Delimiters are treated as equivalent.
Numeric segments are compared mathematically, alphabetic segments are compared lexicographically and case-insensitively. However, the following qualifier strings are recognized and treated specially: "alpha" = "a" < "beta" = "b" < "milestone" = "m" < "cr" = "rc" < "snapshot" < "final" = "ga" < "sp". All of those well-known qualifiers are considered smaller/older than other strings. An empty segment/string is equivalent to 0.
In addition to the above mentioned qualifiers, the tokens "min" and "max" may be used as final version segment to denote the smallest/greatest version having a given prefix. For example, "1.2.min" denotes the smallest version in the 1.2 line, "1.2.max" denotes the greatest version in the 1.2 line. A version range of the form "[M.N.*]" is short for "[M.N.min, M.N.max]".
Numbers and strings are considered incomparable against each other. Where version segments of different kind would collide, comparison will instead assume that the previous segments are padded with trailing 0 or "ga" segments, respectively, until the kind mismatch is resolved, e.g. "1-alpha" = "1.0.0-alpha" < "1.0.1-ga" = "1.0.1".
Stub Runner for Messaging
Stub Runner has the functionality to run the published stubs in memory. It can integrate with the following frameworks out of the box
-
Spring Integration
-
Spring Cloud Stream
-
Apache Camel
-
Spring AMQP
It also provides points of entry to integrate with any other solution on the market.
Stub triggering
To trigger a message it’s enough to use the StubTrigger
interface:
package org.springframework.cloud.contract.stubrunner;
import java.util.Collection;
import java.util.Map;
public interface StubTrigger {
/**
* Triggers an event by a given label for a given {@code groupid:artifactid} notation. You can use only {@code artifactId} too.
*
* Feature related to messaging.
*
* @return true - if managed to run a trigger
*/
boolean trigger(String ivyNotation, String labelName);
/**
* Triggers an event by a given label.
*
* Feature related to messaging.
*
* @return true - if managed to run a trigger
*/
boolean trigger(String labelName);
/**
* Triggers all possible events.
*
* Feature related to messaging.
*
* @return true - if managed to run a trigger
*/
boolean trigger();
/**
* Returns a mapping of ivy notation of a dependency to all the labels it has.
*
* Feature related to messaging.
*/
Map<String, Collection<String>> labels();
}
For convenience the StubFinder
interface extends StubTrigger
so it’s enough to use only one in your tests.
StubTrigger
gives you the following options to trigger a message:
Trigger by label
stubFinder.trigger('return_book_1')
Trigger by group and artifact ids
stubFinder.trigger('org.springframework.cloud.contract.verifier.stubs:camelService', 'return_book_1')
Trigger by artifact ids
stubFinder.trigger('camelService', 'return_book_1')
Trigger all messages
stubFinder.trigger()
Stub Runner Camel
Spring Cloud Contract Verifier Stub Runner’s messaging module gives you an easy way to integrate with Apache Camel. For the provided artifacts it will automatically download the stubs and register the required routes.
Adding it to the project
It’s enough to have both Apache Camel and Spring Cloud Contract Stub Runner on classpath.
Remember to annotate your test class with @AutoConfigureStubRunner
.
Examples
Stubs structure
Let us assume that we have the following Maven repository with a deployed stubs for the
camelService
application.
└── .m2
└── repository
└── io
└── codearte
└── accurest
└── stubs
└── camelService
├── 0.0.1-SNAPSHOT
│ ├── camelService-0.0.1-SNAPSHOT.pom
│ ├── camelService-0.0.1-SNAPSHOT-stubs.jar
│ └── maven-metadata-local.xml
└── maven-metadata-local.xml
And the stubs contain the following structure:
├── META-INF
│ └── MANIFEST.MF
└── repository
├── accurest
│ ├── bookDeleted.groovy
│ ├── bookReturned1.groovy
│ └── bookReturned2.groovy
└── mappings
Let’s consider the following contracts (let' number it with 1):
Contract.make {
label 'return_book_1'
input {
triggeredBy('bookReturnedTriggered()')
}
outputMessage {
sentTo('jms:output')
body('''{ "bookName" : "foo" }''')
headers {
header('BOOK-NAME', 'foo')
}
}
}
and number 2
Contract.make {
label 'return_book_2'
input {
messageFrom('jms:input')
messageBody([
bookName: 'foo'
])
messageHeaders {
header('sample', 'header')
}
}
outputMessage {
sentTo('jms:output')
body([
bookName: 'foo'
])
headers {
header('BOOK-NAME', 'foo')
}
}
}
Scenario 1 (no input message)
So as to trigger a message via the return_book_1
label we’ll use the StubTigger
interface as follows
stubFinder.trigger('return_book_1')
Next we’ll want to listen to the output of the message sent to jms:output
Exchange receivedMessage = camelContext.createConsumerTemplate().receive('jms:output', 5000)
And the received message would pass the following assertions
receivedMessage != null
assertThatBodyContainsBookNameFoo(receivedMessage.in.body)
receivedMessage.in.headers.get('BOOK-NAME') == 'foo'
Scenario 2 (output triggered by input)
Since the route is set for you it’s enough to just send a message to the jms:output
destination.
camelContext.createProducerTemplate().sendBodyAndHeaders('jms:input', new BookReturned('foo'), [sample: 'header'])
Next we’ll want to listen to the output of the message sent to jms:output
Exchange receivedMessage = camelContext.createConsumerTemplate().receive('jms:output', 5000)
And the received message would pass the following assertions
receivedMessage != null
assertThatBodyContainsBookNameFoo(receivedMessage.in.body)
receivedMessage.in.headers.get('BOOK-NAME') == 'foo'
Scenario 3 (input with no output)
Since the route is set for you it’s enough to just send a message to the jms:output
destination.
camelContext.createProducerTemplate().sendBodyAndHeaders('jms:delete', new BookReturned('foo'), [sample: 'header'])
Stub Runner Integration
Spring Cloud Contract Verifier Stub Runner’s messaging module gives you an easy way to integrate with Spring Integration. For the provided artifacts it will automatically download the stubs and register the required routes.
Adding it to the project
It’s enough to have both Spring Integration and Spring Cloud Contract Stub Runner on classpath.
Remember to annotate your test class with @AutoConfigureStubRunner
.
Examples
Stubs structure
Let us assume that we have the following Maven repository with a deployed stubs for the
integrationService
application.
└── .m2
└── repository
└── io
└── codearte
└── accurest
└── stubs
└── integrationService
├── 0.0.1-SNAPSHOT
│ ├── integrationService-0.0.1-SNAPSHOT.pom
│ ├── integrationService-0.0.1-SNAPSHOT-stubs.jar
│ └── maven-metadata-local.xml
└── maven-metadata-local.xml
And the stubs contain the following structure:
├── META-INF
│ └── MANIFEST.MF
└── repository
├── accurest
│ ├── bookDeleted.groovy
│ ├── bookReturned1.groovy
│ └── bookReturned2.groovy
└── mappings
Let’s consider the following contracts (let' number it with 1):
Contract.make {
label 'return_book_1'
input {
triggeredBy('bookReturnedTriggered()')
}
outputMessage {
sentTo('output')
body('''{ "bookName" : "foo" }''')
headers {
header('BOOK-NAME', 'foo')
}
}
}
and number 2
Contract.make {
label 'return_book_2'
input {
messageFrom('input')
messageBody([
bookName: 'foo'
])
messageHeaders {
header('sample', 'header')
}
}
outputMessage {
sentTo('output')
body([
bookName: 'foo'
])
headers {
header('BOOK-NAME', 'foo')
}
}
}
and the following Spring Integration Route:
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/integration"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:beans="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/integration
http://www.springframework.org/schema/integration/spring-integration.xsd">
<!-- REQUIRED FOR TESTING -->
<bridge input-channel="output"
output-channel="outputTest"/>
<channel id="outputTest">
<queue/>
</channel>
</beans:beans>
Scenario 1 (no input message)
So as to trigger a message via the return_book_1
label we’ll use the StubTigger
interface as follows
stubFinder.trigger('return_book_1')
Next we’ll want to listen to the output of the message sent to output
Message<?> receivedMessage = messaging.receive('outputTest')
And the received message would pass the following assertions
receivedMessage != null
assertJsons(receivedMessage.payload)
receivedMessage.headers.get('BOOK-NAME') == 'foo'
Scenario 2 (output triggered by input)
Since the route is set for you it’s enough to just send a message to the output
destination.
messaging.send(new BookReturned('foo'), [sample: 'header'], 'input')
Next we’ll want to listen to the output of the message sent to output
Message<?> receivedMessage = messaging.receive('outputTest')
And the received message would pass the following assertions
receivedMessage != null
assertJsons(receivedMessage.payload)
receivedMessage.headers.get('BOOK-NAME') == 'foo'
Scenario 3 (input with no output)
Since the route is set for you it’s enough to just send a message to the input
destination.
messaging.send(new BookReturned('foo'), [sample: 'header'], 'delete')
Stub Runner Stream
Spring Cloud Contract Verifier Stub Runner’s messaging module gives you an easy way to integrate with Spring Stream. For the provided artifacts it will automatically download the stubs and register the required routes.
Warning
|
In Stub Runner’s integration with Stream the messageFrom or sentTo Strings are resolved
first as a destination of a channel, and then if there is no such destination it’s resolved as a
channel name.
|
Important
|
If you want to use Spring Cloud Stream remember to add a
org.springframework.cloud:spring-cloud-stream-test-support dependency.
|
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-stream-test-support</artifactId>
<scope>test</scope>
</dependency>
testCompile "org.springframework.cloud:spring-cloud-stream-test-support"
Adding it to the project
It’s enough to have both Spring Cloud Stream and Spring Cloud Contract Stub Runner on classpath.
Remember to annotate your test class with @AutoConfigureStubRunner
.
Examples
Stubs structure
Let us assume that we have the following Maven repository with a deployed stubs for the
streamService
application.
└── .m2
└── repository
└── io
└── codearte
└── accurest
└── stubs
└── streamService
├── 0.0.1-SNAPSHOT
│ ├── streamService-0.0.1-SNAPSHOT.pom
│ ├── streamService-0.0.1-SNAPSHOT-stubs.jar
│ └── maven-metadata-local.xml
└── maven-metadata-local.xml
And the stubs contain the following structure:
├── META-INF
│ └── MANIFEST.MF
└── repository
├── accurest
│ ├── bookDeleted.groovy
│ ├── bookReturned1.groovy
│ └── bookReturned2.groovy
└── mappings
Let’s consider the following contracts (let' number it with 1):
Contract.make {
label 'return_book_1'
input { triggeredBy('bookReturnedTriggered()') }
outputMessage {
sentTo('returnBook')
body('''{ "bookName" : "foo" }''')
headers { header('BOOK-NAME', 'foo') }
}
}
and number 2
Contract.make {
label 'return_book_2'
input {
messageFrom('bookStorage')
messageBody([
bookName: 'foo'
])
messageHeaders { header('sample', 'header') }
}
outputMessage {
sentTo('returnBook')
body([
bookName: 'foo'
])
headers { header('BOOK-NAME', 'foo') }
}
}
and the following Spring configuration:
stubrunner.repositoryRoot: classpath:m2repo/repository/
stubrunner.ids: org.springframework.cloud.contract.verifier.stubs:streamService:0.0.1-SNAPSHOT:stubs
spring:
cloud:
stream:
bindings:
output:
destination: returnBook
input:
destination: bookStorage
server:
port: 0
debug: true
Scenario 1 (no input message)
So as to trigger a message via the return_book_1
label we’ll use the StubTrigger
interface as follows
stubFinder.trigger('return_book_1')
Next we’ll want to listen to the output of the message sent to a channel whose destination
is returnBook
Message<?> receivedMessage = messaging.receive('returnBook')
And the received message would pass the following assertions
receivedMessage != null
assertJsons(receivedMessage.payload)
receivedMessage.headers.get('BOOK-NAME') == 'foo'
Scenario 2 (output triggered by input)
Since the route is set for you it’s enough to just send a message to the bookStorage
destination
.
messaging.send(new BookReturned('foo'), [sample: 'header'], 'bookStorage')
Next we’ll want to listen to the output of the message sent to returnBook
Message<?> receivedMessage = messaging.receive('returnBook')
And the received message would pass the following assertions
receivedMessage != null
assertJsons(receivedMessage.payload)
receivedMessage.headers.get('BOOK-NAME') == 'foo'
Scenario 3 (input with no output)
Since the route is set for you it’s enough to just send a message to the output
destination.
messaging.send(new BookReturned('foo'), [sample: 'header'], 'delete')
Stub Runner Spring AMQP
Spring Cloud Contract Verifier Stub Runner’s messaging module provides an easy way to integrate with Spring AMQP’s Rabbit Template. For the provided artifacts it will automatically download the stubs and register the required routes.
The integration tries to work standalone, that is without interaction with a running RabbitMQ message broker.
It expects a RabbitTemplate
on the application context and uses it as a spring boot test @SpyBean
.
Thus it can use the mockito spy functionality to verify and introspect messages sent by the application.
On the message consumer side, it considers all @RabbitListener
annotated endpoints as well as all `SimpleMessageListenerContainer`s on the application context.
As messages are usually sent to exchanges in AMQP the message contract contains the exchange name as the destination. Message listeners on the other side are bound to queues. Bindings connect an exchange to a queue. If message contracts are triggered the Spring AMQP stub runner integration will look for bindings on the application context that match this exchange. Then it collects the queues from the Spring exchanges and tries to find messages listeners bound to these queues. The message is triggered to all matching message listeners.
Adding it to the project
It’s enough to have both Spring AMQP and Spring Cloud Contract Stub Runner on the classpath and set the property stubrunner.amqp.enabled=true
.
Remember to annotate your test class with @AutoConfigureStubRunner
.
Examples
Stubs structure
Let us assume that we have the following Maven repository with a deployed stubs for the
spring-cloud-contract-amqp-test
application.
└── .m2
└── repository
└── com
└── example
└── spring-cloud-contract-amqp-test
├── 0.4.0-SNAPSHOT
│ ├── spring-cloud-contract-amqp-test-0.4.0-SNAPSHOT.pom
│ ├── spring-cloud-contract-amqp-test-0.4.0-SNAPSHOT-stubs.jar
│ └── maven-metadata-local.xml
└── maven-metadata-local.xml
And the stubs contain the following structure:
├── META-INF
│ └── MANIFEST.MF
└── contracts
└── shouldProduceValidPersonData.groovy
Let’s consider the following contract:
Contract.make {
// Human readable description
description 'Should produce valid person data'
// Label by means of which the output message can be triggered
label 'contract-test.person.created.event'
// input to the contract
input {
// the contract will be triggered by a method
triggeredBy('createPerson()')
}
// output message of the contract
outputMessage {
// destination to which the output message will be sent
sentTo 'contract-test.exchange'
headers {
header('contentType': 'application/json')
header('__TypeId__': 'org.springframework.cloud.contract.stubrunner.messaging.amqp.Person')
}
// the body of the output message
body ([
id: $(consumer(9), producer(regex("[0-9]+"))),
name: "me"
])
}
}
and the following Spring configuration:
stubrunner:
repositoryRoot: classpath:m2repo/repository/
ids: org.springframework.cloud.contract.verifier.stubs.amqp:spring-cloud-contract-amqp-test:0.4.0-SNAPSHOT:stubs
amqp:
enabled: true
server:
port: 0
Triggering the message
So to trigger a message using the contract above we’ll use the StubTrigger
interface as follows.
stubTrigger.trigger("contract-test.person.created.event")
The message has the destination contract-test.exchange
so the Spring AMQP stub runner integration looks for bindings related to this exchange.
@Bean
public Binding binding() {
return BindingBuilder.bind(new Queue("test.queue")).to(new DirectExchange("contract-test.exchange")).with("#");
}
The binding definition binds the queue test.queue
.
So the following listener definition is a match and is invoked with the contract message.
@Bean
public SimpleMessageListenerContainer simpleMessageListenerContainer(ConnectionFactory connectionFactory,
MessageListenerAdapter listenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setQueueNames("test.queue");
container.setMessageListener(listenerAdapter);
return container;
}
Also, the following annotated listener represents a match and would be invoked.
@RabbitListener(bindings = @QueueBinding(
value = @Queue(value = "test.queue"),
exchange = @Exchange(value = "contract-test.exchange", ignoreDeclarationExceptions = "true")))
public void handlePerson(Person person) {
this.person = person;
}
Note
|
The message is directly handed over to the onMessage method of the MessageListener associated with the matching SimpleMessageListenerContainer .
|
Spring AMQP Test Configuration
In order to avoid that Spring AMQP is trying to connect to a running broker during our tests we configure a mock ConnectionFactory
.
To disable the mocked ConnectionFactory set the property stubrunner.amqp.mockConnection=false
stubrunner:
amqp:
mockConnection: false
Contract DSL
Important
|
Remember that inside the contract file you have to provide the fully qualified name to
the Contract class and the make static import i.e. org.springframework.cloud.spec.Contract.make { … } .
You can also provide an import to the Contract class import org.springframework.cloud.spec.Contract and then call
Contract.make { … }
|
Contract DSL is written in Groovy, but don’t be alarmed if you didn’t use Groovy before. Knowledge of the language is not really needed as our DSL uses only a tiny subset of it (namely literals, method calls and closures). What’s more the DSL is designed to be programmer-readable without any knowledge of the DSL itself - it’s statically typed.
Tip
|
Spring Cloud Contract supports defining multiple contracts in a single file! |
The Contract is present in the spring-cloud-contract-spec
module of the Spring Cloud Contract Verifier repository.
Let’s look at full example of a contract definition.
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'PUT'
url '/api/12'
headers {
header 'Content-Type': 'application/vnd.org.springframework.cloud.contract.verifier.twitter-places-analyzer.v1+json'
}
body '''\
[{
"created_at": "Sat Jul 26 09:38:57 +0000 2014",
"id": 492967299297845248,
"id_str": "492967299297845248",
"text": "Gonna see you at Warsaw",
"place":
{
"attributes":{},
"bounding_box":
{
"coordinates":
[[
[-77.119759,38.791645],
[-76.909393,38.791645],
[-76.909393,38.995548],
[-77.119759,38.995548]
]],
"type":"Polygon"
},
"country":"United States",
"country_code":"US",
"full_name":"Washington, DC",
"id":"01fbe706f872cb32",
"name":"Washington",
"place_type":"city",
"url": "http://api.twitter.com/1/geo/id/01fbe706f872cb32.json"
}
}]
'''
}
response {
status 200
}
}
Not all features of the DSL are used in example above. If you didn’t find what you are looking for, please check next paragraphs on this page.
You can easily compile Contracts to WireMock stubs mapping using standalone maven command:
mvn org.springframework.cloud:spring-cloud-contract-maven-plugin:convert
.
Limitations
Warning
|
Spring Cloud Contract Verifier doesn’t support XML properly. Please use JSON or help us implement this feature. |
Warning
|
The support for the verification of size of JSON arrays is experimental. If you want to turn it on please provide
the value of a system property spring.cloud.contract.verifier.assert.size equal to true . By default this feature is set to
false . You can also provide the assertJsonSize property in the plugin configuration.
|
Warning
|
Due to the fact that JSON structure can have any form it’s sometimes impossible to parse it properly when using
the value(consumer(…), producer(…)) notation when using that in GString. That’s why we highly recommend using the
Groovy Map notation.
|
Common Top-Level elements
Description
You can add a description
to your contract that is nothing else but an arbitrary text. Example:
org.springframework.cloud.contract.spec.Contract.make {
description('''
given:
An input
when:
Sth happens
then:
Output
''')
}
Name
You can provide a name of your contract. Let’s assume that you’ve provided a name should register a user
.
If you do this then the name of the autogenerated test will be equal to validate_should_register_a_user
.
Also the name of the stub will be should_register_a_user.json
in case of a WireMock stub.
Important
|
Please ensure that the name doesn’t contain any characters that will make the generated test not possible to compile. Also remember that if you provide the same name for multiple contracts then your autogenerated tests will fail to compile and your generated stubs will override each other. |
Ignoring contracts
If you want to ignore a contract you can either set a value of ignored contracts in the plugin configuration
or just set the ignored
property on the contract itself:
org.springframework.cloud.contract.spec.Contract.make {
ignored()
}
HTTP Top-Level Elements
Following methods can be called in the top-level closure of a contract definition. Request and response are mandatory, priority is optional.
org.springframework.cloud.contract.spec.Contract.make {
// Definition of HTTP request part of the contract
// (this can be a valid request or invalid depending
// on type of contract being specified).
request {
//...
}
// Definition of HTTP response part of the contract
// (a service implementing this contract should respond
// with following response after receiving request
// specified in "request" part above).
response {
//...
}
// Contract priority, which can be used for overriding
// contracts (1 is highest). Priority is optional.
priority 1
}
Request
HTTP protocol requires only method and address to be specified in a request. The same information is mandatory in request definition of the Contract.
org.springframework.cloud.contract.spec.Contract.make {
request {
// HTTP request method (GET/POST/PUT/DELETE).
method 'GET'
// Path component of request URL is specified as follows.
urlPath('/users')
}
response {
//...
}
}
It is possible to specify whole url
instead of just path, but urlPath
is the recommended way as it makes the tests host-independent.
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'GET'
// Specifying `url` and `urlPath` in one contract is illegal.
url('http://localhost:8888/users')
}
response {
//...
}
}
Request may contain query parameters, which are specified in a closure nested in a call to urlPath
or url
.
org.springframework.cloud.contract.spec.Contract.make {
request {
//...
urlPath('/users') {
// Each parameter is specified in form
// `'paramName' : paramValue` where parameter value
// may be a simple literal or one of matcher functions,
// all of which are used in this example.
queryParameters {
// If a simple literal is used as value
// default matcher function is used (equalTo)
parameter 'limit': 100
// `equalTo` function simply compares passed value
// using identity operator (==).
parameter 'filter': equalTo("email")
// `containing` function matches strings
// that contains passed substring.
parameter 'gender': value(consumer(containing("[mf]")), producer('mf'))
// `matching` function tests parameter
// against passed regular expression.
parameter 'offset': value(consumer(matching("[0-9]+")), producer(123))
// `notMatching` functions tests if parameter
// does not match passed regular expression.
parameter 'loginStartsWith': value(consumer(notMatching(".{0,2}")), producer(3))
}
}
//...
}
response {
//...
}
}
It may contain additional request headers…
org.springframework.cloud.contract.spec.Contract.make {
request {
//...
// Each header is added in form `'Header-Name' : 'Header-Value'`.
// there are also some helper methods
headers {
header 'key': 'value'
contentType(applicationJson())
}
//...
}
response {
//...
}
}
…and a request body.
org.springframework.cloud.contract.spec.Contract.make {
request {
//...
// Currently only JSON format of request body is supported.
// Format will be determined from a header or body's content.
body '''{ "login" : "john", "name": "John The Contract" }'''
}
response {
//...
}
}
Request may contain multipart elements. Just call the multipart()
method.
org.springframework.cloud.contract.spec.Contract contractDsl = org.springframework.cloud.contract.spec.Contract.make {
request {
method "PUT"
url "/multipart"
headers {
contentType('multipart/form-data;boundary=AaB03x')
}
multipart(
// key (parameter name), value (parameter value) pair
formParameter: $(c(regex('".+"')), p('"formParameterValue"')),
someBooleanParameter: $(c(regex(anyBoolean())), p('true')),
// a named parameter (e.g. with `file` name) that represents file with
// `name` and `content`. You can also call `named("fileName", "fileContent")`
file: named(
// name of the file
name: $(c(regex(nonEmpty())), p('filename.csv')),
// content of the file
content: $(c(regex(nonEmpty())), p('file content')))
)
}
response {
status 200
}
}
In this example we defined parameters either directly by using the map notation,
where the value can be a dynamic property (e.g. formParameter: $(consumer(…), producer(…))
)
or by using the named(…)
method that allows you to set a named parameter.
A named parameter can set a name
and content
. You can call it either via
a method with 2 arguments: e.g. named("fileName", "fileContent")
or
via a map notation named(name: "fileName", content: "fileContent")
.
From this contract the generated test will look more or less like this:
// given:
MockMvcRequestSpecification request = given()
.header("Content-Type", "multipart/form-data;boundary=AaB03x")
.param("formParameter", "\"formParameterValue\"")
.param("someBooleanParameter", "true")
.multiPart("file", "filename.csv", "file content".getBytes());
// when:
ResponseOptions response = given().spec(request)
.put("/multipart");
// then:
assertThat(response.statusCode()).isEqualTo(200);
The WireMock stub will look more or less like this:
'''
{
"request" : {
"url" : "/multipart",
"method" : "PUT",
"headers" : {
"Content-Type" : {
"matches" : "multipart/form-data;boundary=AaB03x.*"
}
},
"bodyPatterns" : [ {
"matches" : ".*--(.*)\\r\\nContent-Disposition: form-data; name=\\"formParameter\\"\\r\\n(Content-Type: .*\\r\\n)?(Content-Length: \\\\d+\\r\\n)?\\r\\n\\".+\\"\\r\\n--\\\\1.*"
}, {
"matches" : ".*--(.*)\\r\\nContent-Disposition: form-data; name=\\"someBooleanParameter\\"\\r\\n(Content-Type: .*\\r\\n)?(Content-Length: \\\\d+\\r\\n)?\\r\\n(true|false)\\r\\n--\\\\1.*"
}, {
"matches" : ".*--(.*)\\r\\nContent-Disposition: form-data; name=\\"file\\"; filename=\\".+\\"\\r\\n(Content-Type: .*\\r\\n)?(Content-Length: \\\\d+\\r\\n)?\\r\\n.+\\r\\n--\\\\1.*"
} ]
},
"response" : {
"status" : 200,
"transformers" : [ "response-template" ]
}
}
'''
Response
Minimal response must contain HTTP status code.
org.springframework.cloud.contract.spec.Contract.make {
request {
//...
}
response {
// Status code sent by the server
// in response to request specified above.
status 200
}
}
Besides status response may contain headers and body, which are specified the same way as in the request (see previous paragraph).
Dynamic properties
The contract can contain some dynamic properties - timestamps / ids etc. You don’t want to enforce the consumers to stub their
clocks to always return the same value of time so that it gets matched by the stub. That’s why we allow you to provide the dynamic
parts in your contracts in two ways. One is to pass them directly in the
body and one to set them in a separate section called testMatchers
and stubMatchers
.
Dynamic properties inside the body
You can set the properties inside the body either via the value
method
value(consumer(...), producer(...))
value(c(...), p(...))
value(stub(...), test(...))
value(client(...), server(...))
or if you’re using the Groovy map notation for body you can use the $()
method
$(consumer(...), producer(...))
$(c(...), p(...))
$(stub(...), test(...))
$(client(...), server(...))
All of the aforementioned approaches are equal. That means that stub
and client
methods are aliases over the consumer
method. Let’s take a closer look at what we can do with those values in the subsequent sections.
Regular expressions
You can use regular expressions to write your requests in Contract DSL. It is particularly useful when you want to indicate that a given response should be provided for requests that follow a given pattern. Also, you can use it when you need to use patterns and not exact values both for your test and your server side tests.
Please see the example below:
org.springframework.cloud.contract.spec.Contract.make {
request {
method('GET')
url $(consumer(~/\/[0-9]{2}/), producer('/12'))
}
response {
status 200
body(
id: $(anyNumber()),
surname: $(
consumer('Kowalsky'),
producer(regex('[a-zA-Z]+'))
),
name: 'Jan',
created: $(consumer('2014-02-02 12:23:43'), producer(execute('currentDate(it)'))),
correlationId: value(consumer('5d1f9fef-e0dc-4f3d-a7e4-72d2220dd827'),
producer(regex('[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}'))
)
)
headers {
header 'Content-Type': 'text/plain'
}
}
}
You can also provide only one side of the communication using a regular expression. If you do that then automatically we’ll provide the generated string that matches the provided regular expression. For example:
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'PUT'
url value(consumer(regex('/foo/[0-9]{5}')))
body([
requestElement: $(consumer(regex('[0-9]{5}')))
])
headers {
header('header', $(consumer(regex('application\\/vnd\\.fraud\\.v1\\+json;.*'))))
}
}
response {
status 200
body([
responseElement: $(producer(regex('[0-9]{7}')))
])
headers {
contentType("application/vnd.fraud.v1+json")
}
}
}
In this example for request and response the opposite side of the communication will have the respective data generated.
Spring Cloud Contract comes with a series of predefined regular expressions that you can use in your contracts.
protected static final Pattern TRUE_OR_FALSE = Pattern.compile(/(true|false)/)
protected static final Pattern ONLY_ALPHA_UNICODE = Pattern.compile(/[\p{L}]*/)
protected static final Pattern NUMBER = Pattern.compile('-?\\d*(\\.\\d+)?')
protected static final Pattern IP_ADDRESS = Pattern.compile('([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])')
protected static final Pattern HOSTNAME_PATTERN = Pattern.compile('((http[s]?|ftp):/)/?([^:/\\s]+)(:[0-9]{1,5})?')
protected static final Pattern EMAIL = Pattern.compile('[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,4}')
protected static final Pattern URL = UrlHelper.URL
protected static final Pattern UUID = Pattern.compile('[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}')
protected static final Pattern ANY_DATE = Pattern.compile('(\\d\\d\\d\\d)-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])')
protected static final Pattern ANY_DATE_TIME = Pattern.compile('([0-9]{4})-(1[0-2]|0[1-9])-(3[01]|0[1-9]|[12][0-9])T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])')
protected static final Pattern ANY_TIME = Pattern.compile('(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])')
protected static final Pattern NON_EMPTY = Pattern.compile(/.+/)
protected static final Pattern NON_BLANK = Pattern.compile(/.*(\S+|\R).*|!^\R*$/)
protected static final Pattern ISO8601_WITH_OFFSET = Pattern.compile(/([0-9]{4})-(1[0-2]|0[1-9])-(3[01]|0[1-9]|[12][0-9])T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\.\d{3})?(Z|[+-][01]\d:[0-5]\d)/)
protected static Pattern anyOf(String... values){
return Pattern.compile(values.collect({"^$it\$"}).join("|"))
}
String onlyAlphaUnicode() {
return ONLY_ALPHA_UNICODE.pattern()
}
String number() {
return NUMBER.pattern()
}
String anyBoolean() {
return TRUE_OR_FALSE.pattern()
}
String ipAddress() {
return IP_ADDRESS.pattern()
}
String hostname() {
return HOSTNAME_PATTERN.pattern()
}
String email() {
return EMAIL.pattern()
}
String url() {
return URL.pattern()
}
String uuid(){
return UUID.pattern()
}
String isoDate() {
return ANY_DATE.pattern()
}
String isoDateTime() {
return ANY_DATE_TIME.pattern()
}
String isoTime() {
return ANY_TIME.pattern()
}
String iso8601WithOffset() {
return ISO8601_WITH_OFFSET.pattern()
}
String nonEmpty() {
return NON_EMPTY.pattern()
}
String nonBlank() {
return NON_BLANK.pattern()
}
so in your contract you can use it like this
Contract dslWithOptionalsInString = Contract.make {
priority 1
request {
method POST()
url '/users/password'
headers {
contentType(applicationJson())
}
body(
email: $(consumer(optional(regex(email()))), producer('[email protected]')),
callback_url: $(consumer(regex(hostname())), producer('http://partners.com'))
)
}
response {
status 404
headers {
contentType(applicationJson())
}
body(
code: value(consumer("123123"), producer(optional("123123"))),
message: "User not found by email = [${value(producer(regex(email())), consumer('[email protected]'))}]"
)
}
}
Passing optional parameters
It is possible to provide optional parameters in your contract. It’s only possible to have optional parameter for the:
-
STUB side of the Request
-
TEST side of the Response
Example:
org.springframework.cloud.contract.spec.Contract.make {
priority 1
request {
method 'POST'
url '/users/password'
headers {
contentType(applicationJson())
}
body(
email: $(consumer(optional(regex(email()))), producer('[email protected]')),
callback_url: $(consumer(regex(hostname())), producer('http://partners.com'))
)
}
response {
status 404
headers {
header 'Content-Type': 'application/json'
}
body(
code: value(consumer("123123"), producer(optional("123123")))
)
}
}
By wrapping a part of the body with the optional()
method you are in fact creating a regular expression that should be present 0 or more times.
That way for the example above the following test would be generated if you pick Spock:
"""
given:
def request = given()
.header("Content-Type", "application/json")
.body('''{"email":"[email protected]","callback_url":"http://partners.com"}''')
when:
def response = given().spec(request)
.post("/users/password")
then:
response.statusCode == 404
response.header('Content-Type') == 'application/json'
and:
DocumentContext parsedJson = JsonPath.parse(response.body.asString())
assertThatJson(parsedJson).field("['code']").matches("(123123)?")
"""
and the following stub:
'''
{
"request" : {
"url" : "/users/password",
"method" : "POST",
"bodyPatterns" : [ {
"matchesJsonPath" : "$[?(@.['email'] =~ /([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\\\.[a-zA-Z]{2,4})?/)]"
}, {
"matchesJsonPath" : "$[?(@.['callback_url'] =~ /((http[s]?|ftp):\\\\/)\\\\/?([^:\\\\/\\\\s]+)(:[0-9]{1,5})?/)]"
} ],
"headers" : {
"Content-Type" : {
"equalTo" : "application/json"
}
}
},
"response" : {
"status" : 404,
"body" : "{\\"code\\":\\"123123\\",\\"message\\":\\"User not found by email == [[email protected]]\\"}",
"headers" : {
"Content-Type" : "application/json"
}
},
"priority" : 1
}
'''
Executing custom methods on server side
It is also possible to define a method call to be executed on the server side during the test. Such a method can be added to the class defined as "baseClassForTests" in the configuration. Example:
Contract
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'PUT'
url $(consumer(regex('^/api/[0-9]{2}$')), producer('/api/12'))
headers {
header 'Content-Type': 'application/json'
}
body '''\
[{
"text": "Gonna see you at Warsaw"
}]
'''
}
response {
body (
path: $(consumer('/api/12'), producer(regex('^/api/[0-9]{2}$'))),
correlationId: $(consumer('1223456'), producer(execute('isProperCorrelationId($it)')))
)
status 200
}
}
Base class
abstract class BaseMockMvcSpec extends Specification {
def setup() {
RestAssuredMockMvc.standaloneSetup(new PairIdController())
}
void isProperCorrelationId(Integer correlationId) {
assert correlationId == 123456
}
void isEmpty(String value) {
assert value == null
}
}
Important
|
You can’t use both a String and execute to perform concatenation. E.g. calling
header('Authorization', 'Bearer ' + execute('authToken()')) will lead to improper results.
To make this work just call header('Authorization', execute('authToken()')) and ensure that
the authToken() method returns everything that you need.
|
The type of the object read from the JSON can be one of the followings depending on the JSON path:
-
String
if you point to aString
value in a JSON -
JSONArray
if you point to aList
in a JSON -
Map
if you point to aMap
in a JSON -
proper
Number
if you point toInteger
,Double
etc. in a JSON -
Boolean
if you point to aBoolean
in a JSON
In the request part of the contract you can specify that the body
should be
taken from a method.
Important
|
You have to provide both the consumer and the producer side
and the execute part can be applied for the whole body. Not for parts of it!
|
Example:
Contract contractDsl = Contract.make {
request {
method 'GET'
url '/something'
body(
$(c("foo"), p(execute("hashCode()")))
)
}
response {
status 200
}
}
This will result in calling the hashCode()
method in the request body.
It would more or less like this:
// given:
MockMvcRequestSpecification request = given()
.body(hashCode());
// when:
ResponseOptions response = given().spec(request)
.get("/something");
// then:
assertThat(response.statusCode()).isEqualTo(200);
Referencing request from response
The best situation is to provide fixed values but sometimes you need to reference a request in your response.
In order to do this you can profit from the fromRequest()
method that allows you to reference a bunch
of elements from the HTTP request. You can use the following options:
-
fromRequest().url()
- return the request URL -
fromRequest().query(String key)
- return the first query parameter with a given name -
fromRequest().query(String key, int index)
- return the nth query parameter with a given name -
fromRequest().header(String key)
- return the first header with a given name -
fromRequest().header(String key, int index)
- return the nth header with a given name -
fromRequest().body()
- return the full request body -
fromRequest().body(String jsonPath)
- return the element from the request that matches the JSON Path
Let’s take a look at the following contract
Contract contractDsl = Contract.make {
request {
method 'GET'
url('/api/v1/xxxx') {
queryParameters {
parameter("foo", "bar")
parameter("foo", "bar2")
}
}
headers {
header(authorization(), "secret")
header(authorization(), "secret2")
}
body(foo: "bar", baz: 5)
}
response {
status 200
headers {
header(authorization(), "foo ${fromRequest().header(authorization())} bar")
}
body(
url: fromRequest().url(),
param: fromRequest().query("foo"),
paramIndex: fromRequest().query("foo", 1),
authorization: fromRequest().header("Authorization"),
authorization2: fromRequest().header("Authorization", 1),
fullBody: fromRequest().body(),
responseFoo: fromRequest().body('$.foo'),
responseBaz: fromRequest().body('$.baz'),
responseBaz2: "Bla bla ${fromRequest().body('$.foo')} bla bla"
)
}
}
Running a JUnit test generation will lead in creation of a test looking more or less like this
// given:
MockMvcRequestSpecification request = given()
.header("Authorization", "secret")
.header("Authorization", "secret2")
.body("{\"foo\":\"bar\",\"baz\":5}");
// when:
ResponseOptions response = given().spec(request)
.queryParam("foo","bar")
.queryParam("foo","bar2")
.get("/api/v1/xxxx");
// then:
assertThat(response.statusCode()).isEqualTo(200);
assertThat(response.header("Authorization")).isEqualTo("foo secret bar");
// and:
DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
assertThatJson(parsedJson).field("url").isEqualTo("/api/v1/xxxx");
assertThatJson(parsedJson).field("fullBody").isEqualTo("{\"foo\":\"bar\",\"baz\":5}");
assertThatJson(parsedJson).field("paramIndex").isEqualTo("bar2");
assertThatJson(parsedJson).field("responseFoo").isEqualTo("bar");
assertThatJson(parsedJson).field("authorization2").isEqualTo("secret2");
assertThatJson(parsedJson).field("responseBaz").isEqualTo(5);
assertThatJson(parsedJson).field("responseBaz2").isEqualTo("Bla bla bar bla bla");
assertThatJson(parsedJson).field("param").isEqualTo("bar");
assertThatJson(parsedJson).field("authorization").isEqualTo("secret");
As you can see elements from the request have been properly referenced in the response.
The generated WireMock stub will look more or less like this:
{
"request" : {
"urlPath" : "/api/v1/xxxx",
"method" : "POST",
"headers" : {
"Authorization" : {
"equalTo" : "secret2"
}
},
"queryParameters" : {
"foo" : {
"equalTo" : "bar2"
}
},
"bodyPatterns" : [ {
"matchesJsonPath" : "$[?(@.baz == 5)]"
}, {
"matchesJsonPath" : "$[?(@.foo == 'bar')]"
} ]
},
"response" : {
"status" : 200,
"body" : "{\"url\":\"{{{request.url}}}\",\"param\":\"{{{request.query.foo.[0]}}}\",\"paramIndex\":\"{{{request.query.foo.[1]}}}\",\"authorization\":\"{{{request.headers.Authorization.[0]}}}\",\"authorization2\":\"{{{request.headers.Authorization.[1]}}}\",\"fullBody\":\"{{{escapejsonbody}}}\",\"responseFoo\":\"{{{jsonpath this '$.foo'}}}\",\"responseBaz\":{{{jsonpath this '$.baz'}}} ,\"responseBaz2\":\"Bla bla {{{jsonpath this '$.foo'}}} bla bla\"}",
"headers" : {
"Authorization" : "{{{request.headers.Authorization.[0]}}}"
},
"transformers" : [ "response-template" ]
}
}
So sending a request as the one presented in the request
part of the contract will lead in sending the following
response body
{
"url" : "/api/v1/xxxx?foo=bar&foo=bar2",
"param" : "bar",
"paramIndex" : "bar2",
"authorization" : "secret",
"authorization2" : "secret2",
"fullBody" : "{\"foo\":\"bar\",\"baz\":5}",
"responseFoo" : "bar",
"responseBaz" : 5,
"responseBaz2" : "Bla bla bar bla bla"
}
Important
|
This feature will work only with WireMock having version greater or equal to 2.5.1. We’re using WireMock’s
response-template response transformer. It’s using Handlebars to convert the Mustache {{{ }}} templates into
proper values. Additionally we’re registering 2 helper functions. escapejsonbody - that escapes the request
body in a format that can be embedded in a JSON. Another is jsonpath that for a given parameter knows how to
find an object in the request body.
|
Dynamic properties in matchers sections
If you’ve been working with Pact this might seem familiar. Quite a few users are used to having a separation between the body and setting dynamic parts of your contract.
That’s why you can profit from two separate sections. One is called stubMatchers
where you can
define the dynamic values that should end up in a stub. You can set it in the request
or inputMessage
part of your contract. The other is called testMatchers
which is present in the response
or
outputMessage
side of the contract.
Currently we support only JSON Path based matchers with the following matching possibilities.
For stubMatchers
:
-
byEquality()
- the value taken from the response via the provided JSON Path needs to be equal to the provided value in the contract -
byRegex(…)
- the value taken from the response via the provided JSON Path needs to match the regex -
byDate()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO Date -
byTimestamp()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO DateTime -
byTime()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO Time
For testMatchers
:
-
byEquality()
- the value taken from the response via the provided JSON Path needs to be equal to the provided value in the contract -
byRegex(…)
- the value taken from the response via the provided JSON Path needs to match the regex -
byDate()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO Date -
byTimestamp()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO DateTime -
byTime()
- the value taken from the response via the provided JSON Path needs to match the regex for ISO Time -
byType()
- the value taken from the response via the provided JSON Path needs to be of the same type as the type defined in the body of the response in the contract.byType
can take a closure where you can setminOccurrence
andmaxOccurrence
. That way you can assert on the size of the collection. -
byCommand(…)
- the value taken from the response via the provided JSON Path will be passed as an input to the custom method that you’re providing. E.g.byCommand('foo($it)')
will result in calling afoo
method to which the value matching the JSON Path will get passed.-
The type of the object read from the JSON can be one of the followings depending on the JSON path:
-
String
if you point to aString
value in a JSON -
JSONArray
if you point to aList
in a JSON -
Map
if you point to aMap
in a JSON -
proper
Number
if you point toInteger
,Double
etc. in a JSON -
Boolean
if you point to aBoolean
in a JSON
-
-
Let’s take a look at the following example:
Contract contractDsl = Contract.make {
request {
method 'GET'
urlPath '/get'
body([
duck: 123,
alpha: "abc",
number: 123,
aBoolean: true,
date: "2017-01-01",
dateTime: "2017-01-01T01:23:45",
time: "01:02:34",
valueWithoutAMatcher: "foo",
valueWithTypeMatch: "string",
key: [
'complex.key' : 'foo'
]
])
stubMatchers {
jsonPath('$.duck', byRegex("[0-9]{3}"))
jsonPath('$.duck', byEquality())
jsonPath('$.alpha', byRegex(onlyAlphaUnicode()))
jsonPath('$.alpha', byEquality())
jsonPath('$.number', byRegex(number()))
jsonPath('$.aBoolean', byRegex(anyBoolean()))
jsonPath('$.date', byDate())
jsonPath('$.dateTime', byTimestamp())
jsonPath('$.time', byTime())
jsonPath("\$.['key'].['complex.key']", byEquality())
}
headers {
contentType(applicationJson())
}
}
response {
status 200
body([
duck: 123,
alpha: "abc",
number: 123,
aBoolean: true,
date: "2017-01-01",
dateTime: "2017-01-01T01:23:45",
time: "01:02:34",
valueWithoutAMatcher: "foo",
valueWithTypeMatch: "string",
valueWithMin: [
1,2,3
],
valueWithMax: [
1,2,3
],
valueWithMinMax: [
1,2,3
],
valueWithMinEmpty: [],
valueWithMaxEmpty: [],
key: [
'complex.key' : 'foo'
]
])
testMatchers {
// asserts the jsonpath value against manual regex
jsonPath('$.duck', byRegex("[0-9]{3}"))
// asserts the jsonpath value against the provided value
jsonPath('$.duck', byEquality())
// asserts the jsonpath value against some default regex
jsonPath('$.alpha', byRegex(onlyAlphaUnicode()))
jsonPath('$.alpha', byEquality())
jsonPath('$.number', byRegex(number()))
jsonPath('$.aBoolean', byRegex(anyBoolean()))
// asserts vs inbuilt time related regex
jsonPath('$.date', byDate())
jsonPath('$.dateTime', byTimestamp())
jsonPath('$.time', byTime())
// asserts that the resulting type is the same as in response body
jsonPath('$.valueWithTypeMatch', byType())
jsonPath('$.valueWithMin', byType {
// results in verification of size of array (min 1)
minOccurrence(1)
})
jsonPath('$.valueWithMax', byType {
// results in verification of size of array (max 3)
maxOccurrence(3)
})
jsonPath('$.valueWithMinMax', byType {
// results in verification of size of array (min 1 & max 3)
minOccurrence(1)
maxOccurrence(3)
})
jsonPath('$.valueWithMinEmpty', byType {
// results in verification of size of array (min 0)
minOccurrence(0)
})
jsonPath('$.valueWithMaxEmpty', byType {
// results in verification of size of array (max 0)
maxOccurrence(0)
})
// will execute a method `assertThatValueIsANumber`
jsonPath('$.duck', byCommand('assertThatValueIsANumber($it)'))
jsonPath("\$.['key'].['complex.key']", byEquality())
}
headers {
contentType(applicationJson())
}
}
}
In this example we’re providing the dynamic portions of the contract in the matchers sections.
For the request part you can see that for all fields but valueWithoutAMatcher
we’re setting
explicitly the values of regular expressions we’d like the stub to contain. For the valueWithoutAMatcher
the verification will take place in the same way as without the usage of matchers - the test
will perform an equality check in this case.
For the response side in the testMatchers
section we’re defining all the dynamic parts
in a similar manner. The only difference is that we have the byType
matchers too. In that
case we’re checking 4 fields in the way that we’re verifying whether the response from the test
has a value whose JSON path matching the given field is of the same type as the one defined in the response body and:
-
for
$.valueWithTypeMatch
- we’re just checking the whether the type is the same -
for
$.valueWithMin
- we’re checking the type and assert if the size is greater or equal to the min occurrence -
for
$.valueWithMax
- we’re checking the type and assert if the size is smaller or equal to the max occurrence -
for
$.valueWithMinMax
- we’re checking the type and assert if the size is between the min and max occurrence
The resulting test would look more or less like this (note that we’re separating the autogenerated
assertions and the one from matchers with an and
section):
// given:
MockMvcRequestSpecification request = given()
.header("Content-Type", "application/json")
.body("{\"duck\":123,\"alpha\":\"abc\",\"number\":123,\"aBoolean\":true,\"date\":\"2017-01-01\",\"dateTime\":\"2017-01-01T01:23:45\",\"time\":\"01:02:34\",\"valueWithoutAMatcher\":\"foo\",\"valueWithTypeMatch\":\"string\"}");
// when:
ResponseOptions response = given().spec(request)
.get("/get");
// then:
assertThat(response.statusCode()).isEqualTo(200);
assertThat(response.header("Content-Type")).matches("application/json.*");
// and:
DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
assertThatJson(parsedJson).field("valueWithoutAMatcher").isEqualTo("foo");
// and:
assertThat(parsedJson.read("$.duck", String.class)).matches("[0-9]{3}");
assertThat(parsedJson.read("$.duck", Integer.class)).isEqualTo(123);
assertThat(parsedJson.read("$.alpha", String.class)).matches("[\\p{L}]*");
assertThat(parsedJson.read("$.alpha", String.class)).isEqualTo("abc");
assertThat(parsedJson.read("$.number", String.class)).matches("-?\\d*(\\.\\d+)?");
assertThat(parsedJson.read("$.aBoolean", String.class)).matches("(true|false)");
assertThat(parsedJson.read("$.date", String.class)).matches("(\\d\\d\\d\\d)-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])");
assertThat(parsedJson.read("$.dateTime", String.class)).matches("([0-9]{4})-(1[0-2]|0[1-9])-(3[01]|0[1-9]|[12][0-9])T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])");
assertThat(parsedJson.read("$.time", String.class)).matches("(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])");
assertThat((Object) parsedJson.read("$.valueWithTypeMatch")).isInstanceOf(java.lang.String.class);
assertThat((Object) parsedJson.read("$.valueWithMin")).isInstanceOf(java.util.List.class);
assertThat(parsedJson.read("$.valueWithMin", java.util.Collection.class)).hasSizeGreaterThanOrEqualTo(1);
assertThat((Object) parsedJson.read("$.valueWithMax")).isInstanceOf(java.util.List.class);
assertThat(parsedJson.read("$.valueWithMax", java.util.Collection.class)).hasSizeLessThanOrEqualTo(3);
assertThat((Object) parsedJson.read("$.valueWithMinMax")).isInstanceOf(java.util.List.class);
assertThat(parsedJson.read("$.valueWithMinMax", java.util.Collection.class)).hasSizeBetween(1, 3);
assertThat((Object) parsedJson.read("$.valueWithMinEmpty")).isInstanceOf(java.util.List.class);
assertThat(parsedJson.read("$.valueWithMinEmpty", java.util.Collection.class)).hasSizeGreaterThanOrEqualTo(0);
assertThat((Object) parsedJson.read("$.valueWithMaxEmpty")).isInstanceOf(java.util.List.class);
assertThat(parsedJson.read("$.valueWithMaxEmpty", java.util.Collection.class)).hasSizeLessThanOrEqualTo(0);
assertThatValueIsANumber(parsedJson.read("$.duck"));
and the WireMock stub like this:
'''
{
"request" : {
"urlPath" : "/get",
"method" : "POST",
"headers" : {
"Content-Type" : {
"matches" : "application/json.*"
}
},
"bodyPatterns" : [ {
"matchesJsonPath" : "$[?(@.['valueWithoutAMatcher'] == 'foo')]"
}, {
"matchesJsonPath" : "$[?(@.['valueWithTypeMatch'] == 'string')]"
}, {
"matchesJsonPath" : "$.['list'].['some'].['nested'][?(@.['anothervalue'] == 4)]"
}, {
"matchesJsonPath" : "$.['list'].['someother'].['nested'][?(@.['anothervalue'] == 4)]"
}, {
"matchesJsonPath" : "$.['list'].['someother'].['nested'][?(@.['json'] == 'with value')]"
}, {
"matchesJsonPath" : "$[?(@.duck =~ /([0-9]{3})/)]"
}, {
"matchesJsonPath" : "$[?(@.duck == 123)]"
}, {
"matchesJsonPath" : "$[?(@.alpha =~ /([\\\\p{L}]*)/)]"
}, {
"matchesJsonPath" : "$[?(@.alpha == 'abc')]"
}, {
"matchesJsonPath" : "$[?(@.number =~ /(-?\\\\d*(\\\\.\\\\d+)?)/)]"
}, {
"matchesJsonPath" : "$[?(@.aBoolean =~ /((true|false))/)]"
}, {
"matchesJsonPath" : "$[?(@.date =~ /((\\\\d\\\\d\\\\d\\\\d)-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01]))/)]"
}, {
"matchesJsonPath" : "$[?(@.dateTime =~ /(([0-9]{4})-(1[0-2]|0[1-9])-(3[01]|0[1-9]|[12][0-9])T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9]))/)]"
}, {
"matchesJsonPath" : "$[?(@.time =~ /((2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9]))/)]"
}, {
"matchesJsonPath" : "$.list.some.nested[?(@.json =~ /(.*)/)]"
} ]
},
"response" : {
"status" : 200,
"body" : "{\\"duck\\":123,\\"alpha\\":\\"abc\\",\\"number\\":123,\\"aBoolean\\":true,\\"date\\":\\"2017-01-01\\",\\"dateTime\\":\\"2017-01-01T01:23:45\\",\\"time\\":\\"01:02:34\\",\\"valueWithoutAMatcher\\":\\"foo\\",\\"valueWithTypeMatch\\":\\"string\\",\\"valueWithMin\\":[1,2,3],\\"valueWithMax\\":[1,2,3],\\"valueWithMinMax\\":[1,2,3]}",
"headers" : {
"Content-Type" : "application/json"
}
}
}
'''
JAX-RS support
We support JAX-RS 2 Client API. Base class needs to define protected WebTarget webTarget
and server initialization, right now the only option how to test JAX-RS API is to start a web server.
Request with a body needs to have a content type set otherwise application/octet-stream
is going to be used.
In order to use JAX-RS mode, use the following settings:
testMode === 'JAXRSCLIENT'
Example of a test API generated:
'''
// when:
Response response = webTarget
.path("/users")
.queryParam("limit", "10")
.queryParam("offset", "20")
.queryParam("filter", "email")
.queryParam("sort", "name")
.queryParam("search", "55")
.queryParam("age", "99")
.queryParam("name", "Denis.Stepanov")
.queryParam("email", "[email protected]")
.request()
.method("GET");
String responseAsString = response.readEntity(String.class);
// then:
assertThat(response.getStatus()).isEqualTo(200);
// and:
DocumentContext parsedJson = JsonPath.parse(responseAsString);
assertThatJson(parsedJson).field("['property1']").isEqualTo("a");
'''
Async support
If you’re using asynchronous communication on the server side (your controllers are returning
Callable
, DeferredResult
etc. then inside your contract you have to provide in the response
section a async()
method. Example:
org.springframework.cloud.contract.spec.Contract.make {
request {
method GET()
url '/get'
}
response {
status 200
body 'Passed'
async()
}
}
Working with Context Paths
Spring Cloud Contract supports context paths.
Important
|
The only thing that changes in order to fully support context paths is the switch on the PRODUCER side. The autogenerated tests need to be using the EXPLICIT mode. |
The consumer side remains untouched, in order for the generated test to pass you have to switch the EXPLICIT mode.
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<testMode>EXPLICIT</testMode>
</configuration>
</plugin>
contracts {
testMode = 'EXPLICIT'
}
That way you’ll generate a test that DOES NOT use MockMvc. It means that you’re generating real requests and you need to setup your generated test’s base class to work on a real socket.
Let’s imagine the following contract:
org.springframework.cloud.contract.spec.Contract.make {
request {
method 'GET'
url '/my-context-path/url'
}
response {
status 200
}
}
Here is an example of how to set up a base class and Rest Assured for everything to work correctly.
import com.jayway.restassured.RestAssured;
import org.junit.Before;
import org.springframework.boot.context.embedded.LocalServerPort;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest(classes = ContextPathTestingBaseClass.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class ContextPathTestingBaseClass {
@LocalServerPort int port;
@Before
public void setup() {
RestAssured.baseURI = "http://localhost";
RestAssured.port = this.port;
}
}
That way all:
-
all your requests in the autogenerated tests will be sent to the real endpoint with your context path included (e.g.
/my-context-path/url
) -
your contracts reflect that you have a context path, thus your generated stubs will also have that information (e.g. in the stubs you’ll see that you have too call
/my-context-path/url
)
Messaging Top-Level Elements
The DSL for messaging looks a little bit different than the one that focuses on HTTP.
Output triggered by a method
The output message can be triggered by calling a method (e.g. a Scheduler was started and a message was sent)
def dsl = Contract.make {
// Human readable description
description 'Some description'
// Label by means of which the output message can be triggered
label 'some_label'
// input to the contract
input {
// the contract will be triggered by a method
triggeredBy('bookReturnedTriggered()')
}
// output message of the contract
outputMessage {
// destination to which the output message will be sent
sentTo('output')
// the body of the output message
body('''{ "bookName" : "foo" }''')
// the headers of the output message
headers {
header('BOOK-NAME', 'foo')
}
}
}
In this case the output message will be sent to output
if a method called bookReturnedTriggered
will be executed. In the message publisher’s side
we will generate a test that will call that method to trigger the message. On the consumer side you can use the some_label
to trigger the message.
Output triggered by a message
The output message can be triggered by receiving a message.
def dsl = Contract.make {
description 'Some Description'
label 'some_label'
// input is a message
input {
// the message was received from this destination
messageFrom('input')
// has the following body
messageBody([
bookName: 'foo'
])
// and the following headers
messageHeaders {
header('sample', 'header')
}
}
outputMessage {
sentTo('output')
body([
bookName: 'foo'
])
headers {
header('BOOK-NAME', 'foo')
}
}
}
In this case the output message will be sent to output
if a proper message will be received on the input
destination. In the message publisher’s side
we will generate a test that will send the input message to the defined destination. On the consumer side you can either send a message to the input
destination or use the some_label
to trigger the message.
Consumer / Producer
In HTTP you have a notion of client
/stub and `server
/test
notation. You can use them also in messaging but we’re providing also the consumer
and produer
methods
as presented below (note you can use either $
or value
methods to provide consumer
and producer
parts)
Contract.make {
label 'some_label'
input {
messageFrom value(consumer('jms:output'), producer('jms:input'))
messageBody([
bookName: 'foo'
])
messageHeaders {
header('sample', 'header')
}
}
outputMessage {
sentTo $(consumer('jms:input'), producer('jms:output'))
body([
bookName: 'foo'
])
}
}
Multiple contracts in one file
It’s possible to define multiple contracts in one file. An example of such a contract can look like this
import org.springframework.cloud.contract.spec.Contract
[
Contract.make {
name("should post a user")
request {
method 'POST'
url('/users/1')
}
response {
status 200
}
},
Contract.make {
request {
method 'POST'
url('/users/2')
}
response {
status 200
}
}
]
In this example one contract has the name
field and the other doesn’t. This will lead to generation of
two tests that will look more or less like this:
package org.springframework.cloud.contract.verifier.tests.com.hello;
import com.example.TestBase;
import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.JsonPath;
import com.jayway.restassured.module.mockmvc.specification.MockMvcRequestSpecification;
import com.jayway.restassured.response.ResponseOptions;
import org.junit.Test;
import static com.jayway.restassured.module.mockmvc.RestAssuredMockMvc.*;
import static com.toomuchcoding.jsonassert.JsonAssertion.assertThatJson;
import static org.assertj.core.api.Assertions.assertThat;
public class V1Test extends TestBase {
@Test
public void validate_should_post_a_user() throws Exception {
// given:
MockMvcRequestSpecification request = given();
// when:
ResponseOptions response = given().spec(request)
.post("/users/1");
// then:
assertThat(response.statusCode()).isEqualTo(200);
}
@Test
public void validate_withList_1() throws Exception {
// given:
MockMvcRequestSpecification request = given();
// when:
ResponseOptions response = given().spec(request)
.post("/users/2");
// then:
assertThat(response.statusCode()).isEqualTo(200);
}
}
Notice that for the contract that has the name
field the generated test method is named
validate_should_post_a_user
. For the one that doesn’t have the name it’s called
validate_withList_1
. It corresponds to the name of the file WithList.groovy
and the
index of the contract in the list.
The generated stubs will look like this
should post a user.json
1_WithList.json
As you can see the first file got the name
parameter from the contract. The second
got the name of the contract file WithList.groovy
prefixed with the index (in this case
contract had index 1
in the list of contracts in the file).
Tip
|
As you can see it’s much better if you name your contracts since then your tests are far more meaningful. |
Customization
Extending the DSL
It is possible to provide your own functions to the DSL. The key requirement for this feature was to maintain the static compatibility. Below you will be able to see an example of:
-
creation of a JAR with reusable classes
-
referencing of these classes in the DSLs
The full example can be found here.
Common JAR
Below you can find three classes that we will reuse in the DSLs.
PatternUtils contains functions used by both the consumer and the producer.
package com.example;
import java.util.regex.Pattern;
/**
* If you want to use {@link Pattern} directly in your tests
* then you can create a class resembling this one. It can
* contain all the {@link Pattern} you want to use in the DSL.
*
* <pre>
* {@code
* request {
* body(
* [ age: $(c(PatternUtils.oldEnough()))]
* )
* }
* </pre>
*
* Notice that we're using both {@code $()} for dynamic values
* and {@code c()} for the consumer side.
*
* @author Marcin Grzejszczak
*/
//tag::impl[]
public class PatternUtils {
public static String tooYoung() {
//remove::start[]
return "[0-1][0-9]";
//remove::end[return]
}
public static Pattern oldEnough() {
//remove::start[]
return Pattern.compile("[2-9][0-9]");
//remove::end[return]
}
/**
* Makes little sense but it's just an example ;)
*/
public static Pattern ok() {
//remove::start[]
return Pattern.compile("OK");
//remove::end[return]
}
}
//end::impl[]
ConsumerUtils contains functions used by the consumer.
package com.example;
import org.springframework.cloud.contract.spec.internal.ClientDslProperty;
/**
* DSL Properties passed to the DSL from the consumer's perspective.
* That means that on the input side {@code Request} for HTTP
* or {@code Input} for messaging you can have a regular expression.
* On the {@code Response} for HTTP or {@code Output} for messaging
* you have to have a concrete value.
*
* @author Marcin Grzejszczak
*/
//tag::impl[]
public class ConsumerUtils {
/**
* Consumer side property. By using the {@link ClientDslProperty}
* you can omit most of boilerplate code from the perspective
* of dynamic values. Example
*
* <pre>
* {@code
* request {
* body(
* [ age: $(ConsumerUtils.oldEnough())]
* )
* }
* </pre>
*
* That way it's in the implementation that we decide what value we will pass to the consumer
* and which one to the producer.
*
* @author Marcin Grzejszczak
*/
public static ClientDslProperty oldEnough() {
//remove::start[]
// this example is not the best one and
// theoretically you could just pass the regex instead of `ServerDslProperty` but
// it's just to show some new tricks :)
return new ClientDslProperty(PatternUtils.oldEnough(), 40);
//remove::end[return]
}
}
//end::impl[]
ProducerUtils contains functions used by the producer.
package com.example;
import org.springframework.cloud.contract.spec.internal.ServerDslProperty;
/**
* DSL Properties passed to the DSL from the producer's perspective.
* That means that on the input side {@code Request} for HTTP
* or {@code Input} for messaging you have to have a concrete value.
* On the {@code Response} for HTTP or {@code Output} for messaging
* you can have a regular expression.
*
* @author Marcin Grzejszczak
*/
//tag::impl[]
public class ProducerUtils {
/**
* Producer side property. By using the {@link ProducerUtils}
* you can omit most of boilerplate code from the perspective
* of dynamic values. Example
*
* <pre>
* {@code
* response {
* body(
* [ status: $(ProducerUtils.ok())]
* )
* }
* </pre>
*
* That way it's in the implementation that we decide what value we will pass to the consumer
* and which one to the producer.
*/
public static ServerDslProperty ok() {
// this example is not the best one and
// theoretically you could just pass the regex instead of `ServerDslProperty` but
// it's just to show some new tricks :)
return new ServerDslProperty( PatternUtils.ok(), "OK");
}
}
//end::impl[]
Adding the dependency to project
In order for the plugins and IDE to be able to reference the common JAR classes you need to pass the dependency to your project.
Test dependency in project’s dependencies
First add the common jar dependency as a test dependency. That way since your contracts files are available at test resources path, automatically the common jar classes will be visible in your Groovy files.
<dependency>
<groupId>com.example</groupId>
<artifactId>beer-common</artifactId>
<version>${project.version}</version>
<scope>test</scope>
</dependency>
testCompile("com.example:beer-common:0.0.1-SNAPSHOT")
Test dependency in plugin’s dependencies
Now you have to add the dependency for the plugin to reuse at runtime.
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example</packageWithBaseClasses>
<baseClassMappings>
<baseClassMapping>
<contractPackageRegex>.*intoxication.*</contractPackageRegex>
<baseClassFQN>com.example.intoxication.BeerIntoxicationBase</baseClassFQN>
</baseClassMapping>
</baseClassMappings>
</configuration>
<dependencies>
<dependency>
<groupId>com.example</groupId>
<artifactId>beer-common</artifactId>
<version>${project.version}</version>
<scope>compile</scope>
</dependency>
</dependencies>
</plugin>
classpath "com.example:beer-common:0.0.1-SNAPSHOT"
Referencing classes in DSLs
Now you can reference your classes in your DSL. Example:
package contracts.beer.rest
import com.example.ConsumerUtils
import com.example.ProducerUtils
import org.springframework.cloud.contract.spec.Contract
Contract.make {
description("""
Represents a successful scenario of getting a beer
```
given:
client is old enough
when:
he applies for a beer
then:
we'll grant him the beer
```
""")
request {
method 'POST'
url '/check'
body(
age: $(ConsumerUtils.oldEnough())
)
headers {
contentType(applicationJson())
}
}
response {
status 200
body("""
{
"status": "${value(ProducerUtils.ok())}"
}
""")
headers {
contentType(applicationJson())
}
}
}
Pluggable architecture
There are cases where you have your contracts defined in other formats like YAML, RAML or PACT. On the other hand you’d like to profit from the test and stubs generation. It’s really easy to add your own implementation of either of those. Also you can customize the way tests are generated (for example you can generate tests for other languages) and you can do the same for stubs generation (you can generate stubs for other stub http server implementations).
Custom contract converter
Let’s assume that your contract is written in a YAML file like this:
request:
url: /foo
method: PUT
headers:
foo: bar
body:
foo: bar
response:
status: 200
headers:
foo2: bar
body:
foo2: bar
Thanks to the interface
package org.springframework.cloud.contract.spec
/**
* Converter to be used to convert FROM {@link File} TO {@link Contract}
* and from {@link Contract} to {@code T}
*
* @param <T> - type to which we want to convert the contract
*
* @author Marcin Grzejszczak
* @since 1.1.0
*/
interface ContractConverter<T> {
/**
* Should this file be accepted by the converter. Can use the file extension
* to check if the conversion is possible.
*
* @param file - file to be considered for conversion
* @return - {@code true} if the given implementation can convert the file
*/
boolean isAccepted(File file)
/**
* Converts the given {@link File} to its {@link Contract} representation
*
* @param file - file to convert
* @return - {@link Contract} representation of the file
*/
Collection<Contract> convertFrom(File file)
/**
* Converts the given {@link Contract} to a {@link T} representation
*
* @param contract - the parsed contract
* @return - {@link T} the type to which we do the conversion
*/
T convertTo(Collection<Contract> contract)
}
you can register your own implementation of a contract structure converter. Your implementation needs to state the condition on which it should start the conversion. Also you have to define how to perform that conversion in both ways.
Important
|
Once you create your implementation you have to create a /META-INF/spring.factories
file in which you provide the fully qualified name of your implementation.
|
Example of a spring.factories
file
# Converters
org.springframework.cloud.contract.spec.ContractConverter=\
org.springframework.cloud.contract.verifier.converter.YamlContractConverter
and the YAML implementation
package org.springframework.cloud.contract.verifier.converter
import groovy.transform.CompileStatic
import org.springframework.cloud.contract.spec.Contract
import org.springframework.cloud.contract.spec.ContractConverter
import org.springframework.cloud.contract.spec.internal.Headers
import org.yaml.snakeyaml.Yaml
/**
* Simple converter from and to a {@link YamlContract} to a collection of {@link Contract}
*/
@CompileStatic
class YamlContractConverter implements ContractConverter<List<YamlContract>> {
@Override
public boolean isAccepted(File file) {
String name = file.getName()
return name.endsWith(".yml") || name.endsWith(".yaml")
}
@Override
public Collection<Contract> convertFrom(File file) {
try {
YamlContract yamlContract = new Yaml().loadAs(new FileInputStream(file), YamlContract.class)
return [Contract.make {
request {
method(yamlContract?.request?.method)
url(yamlContract?.request?.url)
headers {
yamlContract?.request?.headers?.each { String key, Object value ->
header(key, value)
}
}
body(yamlContract?.request?.body)
}
response {
status(yamlContract?.response?.status)
headers {
yamlContract?.response?.headers?.each { String key, Object value ->
header(key, value)
}
}
body(yamlContract?.response?.body)
}
}]
}
catch (FileNotFoundException e) {
throw new IllegalStateException(e)
}
}
@Override
public List<YamlContract> convertTo(Collection<Contract> contracts) {
return contracts.collect { Contract contract ->
YamlContract yamlContract = new YamlContract()
yamlContract.request.with {
method = contract?.request?.method?.clientValue
url = contract?.request?.url?.clientValue
headers = (contract?.request?.headers as Headers)?.asStubSideMap()
body = contract?.request?.body?.clientValue as Map
}
yamlContract.response.with {
status = contract?.response?.status?.clientValue as Integer
headers = (contract?.response?.headers as Headers)?.asStubSideMap()
body = contract?.response?.body?.clientValue as Map
}
return yamlContract
}
}
}
Pact converter
Spring Cloud Contract comes with an out of the box support for Pact representation of contracts. In other words instead of using the Groovy DSL you can use Pact files. In this section we will present how to add such a support for your project.
Pact contract
We will be working on the following example of a Pact contract. We’ve placed this file under
the src/test/resources/contracts
folder.
{
"provider": {
"name": "Provider"
},
"consumer": {
"name": "Consumer"
},
"interactions": [
{
"description": "",
"request": {
"method": "PUT",
"path": "/fraudcheck",
"headers": {
"Content-Type": "application/vnd.fraud.v1+json"
},
"body": {
"clientId": "1234567890",
"loanAmount": 99999
},
"matchingRules": {
"$.body.clientId": {
"match": "regex",
"regex": "[0-9]{10}"
}
}
},
"response": {
"status": 200,
"headers": {
"Content-Type": "application/vnd.fraud.v1+json;charset=UTF-8"
},
"body": {
"fraudCheckStatus": "FRAUD",
"rejectionReason": "Amount too high"
},
"matchingRules": {
"$.body.fraudCheckStatus": {
"match": "regex",
"regex": "FRAUD"
}
}
}
}
],
"metadata": {
"pact-specification": {
"version": "2.0.0"
},
"pact-jvm": {
"version": "2.4.18"
}
}
}
Pact for producers
On the producer side you have add to your plugin configuration two additional dependencies. One is the Spring Cloud Contract Pact support and the other represents the current Pact version that you’re using.
<plugin>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-maven-plugin</artifactId>
<version>${spring-cloud-contract.version}</version>
<extensions>true</extensions>
<configuration>
<packageWithBaseClasses>com.example.fraud</packageWithBaseClasses>
</configuration>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-spec-pact</artifactId>
<version>${spring-cloud-contract.version}</version>
</dependency>
<dependency>
<groupId>au.com.dius</groupId>
<artifactId>pact-jvm-model</artifactId>
<version>2.4.18</version>
</dependency>
</dependencies>
</plugin>
classpath "org.springframework.cloud:spring-cloud-contract-spec-pact:${findProperty('verifierVersion') ?: verifierVersion}"
classpath 'au.com.dius:pact-jvm-model:2.4.18'
When you execute the build of your application a test, looking more or less like this, will be generated
@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
// given:
MockMvcRequestSpecification request = given()
.header("Content-Type", "application/vnd.fraud.v1+json")
.body("{\"clientId\":\"1234567890\",\"loanAmount\":99999}");
// when:
ResponseOptions response = given().spec(request)
.put("/fraudcheck");
// then:
assertThat(response.statusCode()).isEqualTo(200);
assertThat(response.header("Content-Type")).isEqualTo("application/vnd.fraud.v1+json;charset=UTF-8");
// and:
DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
assertThatJson(parsedJson).field("rejectionReason").isEqualTo("Amount too high");
// and:
assertThat(parsedJson.read("$.fraudCheckStatus", String.class)).matches("FRAUD");
}
and the stub looking like this
{
"uuid" : "996ae5ae-6834-4db6-8fac-358ca187ab62",
"request" : {
"url" : "/fraudcheck",
"method" : "PUT",
"headers" : {
"Content-Type" : {
"equalTo" : "application/vnd.fraud.v1+json"
}
},
"bodyPatterns" : [ {
"matchesJsonPath" : "$[?(@.loanAmount == 99999)]"
}, {
"matchesJsonPath" : "$[?(@.clientId =~ /([0-9]{10})/)]"
} ]
},
"response" : {
"status" : 200,
"body" : "{\"fraudCheckStatus\":\"FRAUD\",\"rejectionReason\":\"Amount too high\"}",
"headers" : {
"Content-Type" : "application/vnd.fraud.v1+json;charset=UTF-8"
}
}
}
Pact for consumers
On the producer side you have add to your project dependencies two additional dependencies. One is the Spring Cloud Contract Pact support and the other represents the current Pact version that you’re using.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-contract-spec-pact</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>au.com.dius</groupId>
<artifactId>pact-jvm-model</artifactId>
<version>2.4.18</version>
<scope>test</scope>
</dependency>
testCompile "org.springframework.cloud:spring-cloud-contract-spec-pact"
testCompile 'au.com.dius:pact-jvm-model:2.4.18'
Custom test generator
If you want to generate tests for different languages than Java or you’re not happy with the way we’re building Java tests for you then you can register your own implementation to do that.
Thanks to the interface
package org.springframework.cloud.contract.verifier.builder
import org.springframework.cloud.contract.verifier.config.ContractVerifierConfigProperties
import org.springframework.cloud.contract.verifier.file.ContractMetadata
/**
* Builds a single test.
*
* @since 1.1.0
*/
interface SingleTestGenerator {
/**
* Creates contents of a single test class in which all test scenarios from
* the contract metadata should be placed.
*
* @param properties - properties passed to the plugin
* @param listOfFiles - list of parsed contracts with additional metadata
* @param className - the name of the generated test class
* @param classPackage - the name of the package in which the test class should be stored
* @param includedDirectoryRelativePath - relative path to the included directory
* @return contents of a single test class
*/
String buildClass(ContractVerifierConfigProperties properties, Collection<ContractMetadata> listOfFiles,
String className, String classPackage, String includedDirectoryRelativePath)
/**
* Extension that should be appended to the generated test class. E.g. {@code .java} or {@code .php}
*
* @param properties - properties passed to the plugin
*/
String fileExtension(ContractVerifierConfigProperties properties)
}
you can register your own implementation that generates a test. Again, it’s enough to provide
a proper spring.factories
file. Example:
org.springframework.cloud.contract.verifier.builder.SingleTestGenerator=/
com.example.MyGenerator
Custom stub generator
If you want to generate stubs for other stub server than WireMock it’s enough to plug in your own implementation of this interface:
package org.springframework.cloud.contract.verifier.converter
import groovy.transform.CompileStatic
import org.springframework.cloud.contract.spec.Contract
import org.springframework.cloud.contract.verifier.file.ContractMetadata
/**
* Converts contracts into their stub representation.
*
* @since 1.1.0
*/
@CompileStatic
interface StubGenerator {
/**
* Returns {@code true} if the converter can handle the file to convert it into a stub.
*/
boolean canHandleFileName(String fileName)
/**
* Returns the collection of converted contracts into stubs. One contract can
* result in multiple stubs.
*/
Map<Contract, String> convertContents(String rootName, ContractMetadata content)
/**
* Returns the name of the converted stub file. If you have multiple contracts
* in a single file then a prefix will be added to the generated file. If you
* provide the {@link Contract#name} field then that field will override the
* generated file name.
*
* Example: name of file with 2 contracts is {@code foo.groovy}, it will be
* converted by the implementation to {@code foo.json}. The recursive file
* converter will create two files {@code 0_foo.json} and {@code 1_foo.json}
*/
String generateOutputFileNameForInput(String inputFileName)
}
you can register your own implementation that generate Stubs. Again, it’s enough to provide
a proper spring.factories
file. Example:
# Stub converters
org.springframework.cloud.contract.verifier.converter.StubGenerator=\
org.springframework.cloud.contract.verifier.wiremock.DslToWireMockClientConverter
The default implementation is the WireMock stub generation.
Tip
|
You can provide multiple stub generator implementations. That way for example from a single DSL as input you can e.g. produce WireMock stubs and Pact files too! |
Custom Stub Runner
If you decide to have a custom stub generation you also need a custom way of running stubs with your different stub provider.
Let us assume that you’re using Moco to build your stubs. You wrote a proper stub generator and your stubs got placed in a JAR file.
In order for Stub Runner to know how to run your stubs you have to define a custom HTTP Stub server implementation. It can look like this:
package org.springframework.cloud.contract.stubrunner.provider.moco
import com.github.dreamhead.moco.bootstrap.arg.HttpArgs
import com.github.dreamhead.moco.runner.JsonRunner
import com.github.dreamhead.moco.runner.RunnerSetting
import groovy.util.logging.Slf4j
import org.springframework.cloud.contract.stubrunner.HttpServerStub
import org.springframework.util.SocketUtils
@Slf4j
class MocoHttpServerStub implements HttpServerStub {
private boolean started
private JsonRunner runner
private int port
@Override
int port() {
if (!isRunning()) {
return -1
}
return port
}
@Override
boolean isRunning() {
return started
}
@Override
HttpServerStub start() {
return start(SocketUtils.findAvailableTcpPort())
}
@Override
HttpServerStub start(int port) {
this.port = port
return this
}
@Override
HttpServerStub stop() {
if (!isRunning()) {
return this
}
this.runner.stop()
return this
}
@Override
HttpServerStub registerMappings(Collection<File> stubFiles) {
List<RunnerSetting> settings = stubFiles.findAll { it.name.endsWith("json") }
.collect {
log.info("Trying to parse [{}]", it.name)
try {
return RunnerSetting.aRunnerSetting().withStream(it.newInputStream()).build()
} catch (Exception e) {
log.warn("Exception occurred while trying to parse file [{}]", it.name, e)
return null
}
}.findAll { it }
this.runner = JsonRunner.newJsonRunnerWithSetting(settings,
HttpArgs.httpArgs().withPort(this.port).build())
this.runner.run()
this.started = true
return this
}
@Override
boolean isAccepted(File file) {
return file.name.endsWith(".json")
}
}
and just register it in your spring.factories
file
org.springframework.cloud.contract.stubrunner.HttpServerStub=\
org.springframework.cloud.contract.stubrunner.provider.moco.MocoHttpServerStub
that way you’ll be able to run stubs using Moco.
Important
|
If you don’t provide any implementation then the default one - WireMock based will be picked. If you provide more than one then the first one on the list will be picked. |
Custom Stub Downloader
You can customize the way your stubs are downloaded. It’s enough to create an
implementation of the StubDownloaderBuilder
package com.example;
class CustomStubDownloaderBuilder implements StubDownloaderBuilder {
@Override
public StubDownloader build(final StubRunnerOptions stubRunnerOptions) {
return new StubDownloader() {
@Override
public Map.Entry<StubConfiguration, File> downloadAndUnpackStubJar(
StubConfiguration config) {
File unpackedStubs = retrieveStubs();
return new AbstractMap.SimpleEntry<>(
new StubConfiguration(config.getGroupId(), config.getArtifactId(), version,
config.getClassifier()), unpackedStubs);
}
File retrieveStubs() {
// here goes your custom logic to provide a folder where all the stubs reside
}
}
and just register it in your spring.factories
file
# Example of a custom Stub Downloader Provider
org.springframework.cloud.contract.stubrunner.StubDownloaderBuilder=\
com.example.CustomStubDownloaderBuilder
that way you’ll be able to pick a folder with the source of your stubs.
Important
|
If you don’t provide any implementation then the default one will be picked.
If you provide repositoryRoot property or workOffline flag then Aether based
that will download stubs from a remote repo will be picked. If you don’t provide these
values then the ClasspathStubProvider will be picked that will scan the classpath.
If you provide more than one, then the first one on the list will be picked.
|
Links
Here you can find interesting links related to Spring Cloud Contract Verifier:
Spring Cloud Contract WireMock
Modules giving you the possibility to use WireMock with different servers by using the "ambient" server embedded in a Spring Boot application. Check out the samples for more details.
Important
|
The Spring Cloud Release Train BOM imports spring-cloud-contract-dependencies
which in turn has exclusions for the dependencies needed by WireMock. This might lead to a situation that
even if you’re not using Spring Cloud Contract then your dependencies will be influenced
anyways.
|
If you have a Spring Boot application that uses Tomcat as an embedded
server, for example (the default with spring-boot-starter-web
), then
you can simply add spring-cloud-contract-wiremock
to your classpath
and add @AutoConfigureWireMock
in order to be able to use Wiremock
in your tests. Wiremock runs as a stub server and you can register
stub behaviour using a Java API or via static JSON declarations as
part of your test. Here’s a simple example:
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
@AutoConfigureWireMock(port = 0)
public class WiremockForDocsTests {
// A service that calls out over HTTP
@Autowired private Service service;
// Using the WireMock APIs in the normal way:
@Test
public void contextLoads() throws Exception {
// Stubbing WireMock
stubFor(get(urlEqualTo("/resource"))
.willReturn(aResponse().withHeader("Content-Type", "text/plain").withBody("Hello World!")));
// We're asserting if WireMock responded properly
assertThat(this.service.go()).isEqualTo("Hello World!");
}
}
To start the stub server on a different port use @AutoConfigureWireMock(port=9999)
(for example), and for a random port use the value 0. The stub server port will be bindable in the test application context as "wiremock.server.port". Using @AutoConfigureWireMock
adds a bean of type WiremockConfiguration
to your test application context, where it will be cached in between methods and classes having the same context, just like for normal Spring integration tests.
Registering Stubs Automatically
If you use @AutoConfigureWireMock
then it will register WireMock
JSON stubs from the file system or classpath, by default from
file:src/test/resources/mappings
. You can customize the locations
using the stubs
attribute in the annotation, which can be a resource
pattern (ant-style) or a directory, in which case */.json
is
appended. Example:
@RunWith(SpringRunner.class) @SpringBootTest @AutoConfigureWireMock(stubs="classpath:/stubs") public class WiremockImportApplicationTests { @Autowired private Service service; @Test public void contextLoads() throws Exception { assertThat(this.service.go()).isEqualTo("Hello World!"); } }
Note
|
Actually WireMock always loads mappings from
src/test/resources/mappings as well as the custom locations in the
stubs attribute. To change this behaviour you have to also specify a
files root as described next.
|
Using Files to Specify the Stub Bodies
WireMock can read response bodies from files on the classpath or file
system. In that case you will see in the JSON DSL that the response
has a "bodyFileName" instead of a (literal) "body". The files are
resolved relative to a root directory src/test/resources/__files
by
default. To customize this location you can set the files
attribute
in the @AutoConfigureWireMock
annotation to the location of the
parent directory (i.e. the place __files
is a
subdirectory). You can use Spring resource notation to refer to
file:…
or classpath:…
locations (but generic URLs are not
supported). A list of values can be given and WireMock will resolve
the first file that exists when it needs to find a response body.
Note
|
when you configure the files root, then it affects the
automatic loading of stubs as well (they come from the root location
in a subdirectory called "mappings"). The value of files has no
effect on the stubs loaded explicitly from the stubs attribute.
|
Alternative: Using JUnit Rules
For a more conventional WireMock experience, using JUnit @Rules
to
start and stop the server, just use the WireMockSpring
convenience
class to obtain an Options
instance:
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class WiremockForDocsClassRuleTests {
// Start WireMock on some dynamic port
// for some reason `dynamicPort()` is not working properly
@ClassRule
public static WireMockClassRule wiremock = new WireMockClassRule(
WireMockSpring.options().dynamicPort());
// A service that calls out over HTTP to localhost:${wiremock.port}
@Autowired
private Service service;
// Using the WireMock APIs in the normal way:
@Test
public void contextLoads() throws Exception {
// Stubbing WireMock
wiremock.stubFor(get(urlEqualTo("/resource"))
.willReturn(aResponse().withHeader("Content-Type", "text/plain").withBody("Hello World!")));
// We're asserting if WireMock responded properly
assertThat(this.service.go()).isEqualTo("Hello World!");
}
}
The use @ClassRule
means that the server will shut down after all the methods in this class.
Relaxed SSL Validation for Rest Template
WireMock allows you to stub a "secure" server with an "https" URL protocol. If your application wants to contact that stub server in an integration test, then it will find that the SSL certificates are not valid (it’s the usual problem with self-installed certificates). The best option is often to just re-configure the client to use "http", but if that’s not open to you then you can ask Spring to configure an HTTP client that ignores SSL validation errors (just for tests).
To make this work with minimum fuss you need to be using the Spring Boot RestTemplateBuilder
in your app,
e.g.
@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
return builder.build();
}
This is because the builder is passed through callbacks to initalize it, so the SSL validation can be set up
in the client at that point. This will happen automatically in your test if you are using the
@AutoConfigureWireMock
annotation (or the stub runner). If you are using the JUnit @Rule
approach you need
to add the @AutoConfigureHttpClient
annotation as well:
@RunWith(SpringRunner.class)
@SpringBootTest("app.baseUrl=https://localhost:6443")
@AutoConfigureHttpClient
public class WiremockHttpsServerApplicationTests {
@ClassRule
public static WireMockClassRule wiremock = new WireMockClassRule(
WireMockSpring.options().httpsPort(6443));
...
}
If you are using spring-boot-starter-test
then you will have the Apache HTTP client on the classpath and it will
be selected by the RestTemplateBuilder
and configured to ignore SSL errors. If you are using the default java.net
client you don’t need the annotation (but it won’t do any harm). There is no support currently for other clients, but
it may be added in future releases.
WireMock and Spring MVC Mocks
Spring Cloud Contract provides a convenience class that can load JSON WireMock stubs into a
Spring MockRestServiceServer
. Here’s an example:
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.NONE)
public class WiremockForDocsMockServerApplicationTests {
@Autowired
private RestTemplate restTemplate;
@Autowired
private Service service;
@Test
public void contextLoads() throws Exception {
// will read stubs classpath
MockRestServiceServer server = WireMockRestServiceServer.with(this.restTemplate)
.baseUrl("http://example.org").stubs("classpath:/stubs/resource.json")
.build();
// We're asserting if WireMock responded properly
assertThat(this.service.go()).isEqualTo("Hello World");
server.verify();
}
}
The baseUrl
is prepended to all mock calls, and the stubs()
method takes a stub path resource pattern as an argument. So in this
example the stub defined at /stubs/resource.json
is loaded into the
mock server, so if the RestTemplate
is asked to visit
http://example.org/
it will get the responses as declared
there. More than one stub pattern can be specified, and each one can
be a directory (for a recursive list of all ".json"), or a fixed
filename (like in the example above) or an ant-style pattern. The JSON
format is the normal WireMock format which you can read about in the
WireMock website.
Currently we support Tomcat, Jetty and Undertow as Spring Boot embedded servers, and Wiremock itself has "native" support for a particular version of Jetty (currently 9.2). To use the native Jetty you need to add the native wiremock dependencies and exclude the Spring Boot container if there is one.
Generating Stubs using RestDocs
Spring RestDocs can be
used to generate documentation (e.g. in asciidoctor format) for an
HTTP API with Spring MockMvc or Rest Assured. At the same time as you
generate documentation for your API, you can also generate WireMock
stubs, by using Spring Cloud Contract WireMock. Just write your normal
RestDocs test cases and use @AutoConfigureRestDocs
to have stubs
automatically in the restdocs output directory. For example:
@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureRestDocs(outputDir = "target/snippets")
@AutoConfigureMockMvc
public class ApplicationTests {
@Autowired
private MockMvc mockMvc;
@Test
public void contextLoads() throws Exception {
mockMvc.perform(get("/resource"))
.andExpect(content().string("Hello World"))
.andDo(document("resource"));
}
}
From this test will be generated a WireMock stub at "target/snippets/stubs/resource.json". It matches all GET requests to the "/resource" path.
Without any additional configuration this will create a stub with a request matcher for the HTTP method and all headers except "host" and "content-length". To match the request more precisely, for example to match the body of a POST or PUT, we need to explicitly create a request matcher. This will do two things: 1) create a stub that only matches the way you specify, 2) assert that the request in the test case also matches the same conditions.
The main entry point for this is WireMockRestDocs.verify()
which can
be used as a substitute for the document()
convenience method. For
example:
@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureRestDocs(outputDir = "target/snippets")
@AutoConfigureMockMvc
public class ApplicationTests {
@Autowired
private MockMvc mockMvc;
@Test
public void contextLoads() throws Exception {
mockMvc.perform(post("/resource")
.content("{\"id\":\"123456\",\"message\":\"Hello World\"}"))
.andExpect(status().isOk())
.andDo(verify().jsonPath("$.id")
.stub("resource"));
}
}
So this contract is saying: any valid POST with an "id" field will get
back an the same response as in this test. You can chain together
calls to .jsonPath()
to add additional matchers. The
JayWay documentation can help you
to get up to speed with JSON Path if it is unfamiliar to you.
Instead of the jsonPath
and contentType
convenience methods, you
can also use the WireMock APIs to verify the request matches the
created stub. Example:
@Test
public void contextLoads() throws Exception {
mockMvc.perform(post("/resource")
.content("{\"id\":\"123456\",\"message\":\"Hello World\"}"))
.andExpect(status().isOk())
.andDo(verify()
.wiremock(WireMock.post(
urlPathEquals("/resource"))
.withRequestBody(matchingJsonPath("$.id"))
.stub("post-resource"));
}
The WireMock API is rich - you can match headers, query parameters, and request body by regex as well as by json path - so this can useful to create stubs with a wider range of parameters. The above example will generate a stub something like this:
{
"request" : {
"url" : "/resource",
"method" : "POST",
"bodyPatterns" : [ {
"matchesJsonPath" : "$.id"
}]
},
"response" : {
"status" : 200,
"body" : "Hello World",
"headers" : {
"X-Application-Context" : "application:-1",
"Content-Type" : "text/plain"
}
}
}
Note
|
You can use either the wiremock() method or the jsonPath()
and contentType() methods to create request matchers, but not both.
|
On the consumer side, you can make the resource.json
generated above
available on the classpath (by publishing stubs as JARs for example).
After that, you can create a stub using WireMock in a
number of different ways, including as described above using
@AutoConfigureWireMock(stubs="classpath:resource.json")
.
Generating Contracts using RestDocs
Another thing that can be generated with Spring RestDocs is the Spring Cloud Contract DSL file and documentation. If you combine that with Spring Cloud WireMock then you’re getting both the contracts and stubs.
Why would you want to use this feature? Some people in the community asked questions about situation in which they would like to move to DSL based contract definition but they already have a lot of Spring MVC tests. Using this feature allows you to generate the contract files that you can later modify and move to proper folders so that the plugin picks them up.
Tip
|
You might wonder why this functionality is in the WireMock module. Come to think of it, it does make sense since it makes little sense to generate only contracts and not generate the stubs. That’s why we suggest to do both. |
Let’s imagine the following test:
this.mockMvc.perform(post("/foo")
.accept(MediaType.APPLICATION_PDF)
.accept(MediaType.APPLICATION_JSON)
.contentType(MediaType.APPLICATION_JSON)
.content("{\"foo\": 23 }"))
.andExpect(status().isOk())
.andExpect(content().string("bar"))
// first WireMock
.andDo(WireMockRestDocs.verify()
.jsonPath("$[?(@.foo >= 20)]")
.contentType(MediaType.valueOf("application/json"))
.stub("shouldGrantABeerIfOldEnough"))
// then Contract DSL documentation
.andDo(document("index", SpringCloudContractRestDocs.dslContract()));
This will lead in the creation of the stub as presented in the previous section, contract will get generated and a documentation file too.
The contract will be called index.groovy
and look more like this.
import org.springframework.cloud.contract.spec.Contract
Contract.make {
request {
method 'POST'
url '/foo'
body('''
{"foo": 23 }
''')
headers {
header('''Accept''', '''application/json''')
header('''Content-Type''', '''application/json''')
}
}
response {
status 200
body('''
bar
''')
headers {
header('''Content-Type''', '''application/json;charset=UTF-8''')
header('''Content-Length''', '''3''')
}
testMatchers {
jsonPath('$[?(@.foo >= 20)]', byType())
}
}
}
the generated document (example for Asciidoc) will contain a formatted contract
(the location of this file would be index/dsl-contract.adoc
).