5. Spring Cloud Contract Stub Runner

You can pick the following options of acquiring stubs

The latter example is described in the Custom Stub Runner section.

@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

Maven. 

<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>

Gradle. 

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.

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.

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.

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());

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

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.

Which you can reference in your code.

The most important feature of Stub Runner Spring Cloud is the fact that it’s stubbing

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

stubrunner:
  idsToServiceIds:
    ivyNotation: someValueInsideYourCode
    fraudDetectionServer: someNameThatShouldMapFraudDetectionServer

    //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");
    }

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.

@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=")
	}

}

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.

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:

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.

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: