Provider Contract Testing with Stubs in Artifactory for a non-Spring Application

In this page you will learn how to do provider contract testing with a non-Spring application and stubs uploaded to Artifactory.

The Flow

You can read Developing Your First Spring Cloud Contract-based Application to see the flow for provider contract testing with stubs in Nexus or Artifactory.

Setting up the Consumer

For the consumer side, you can use a JUnit rule. That way, you need not start a Spring context. The following listing shows such a rule (in JUnit4 and JUnit 5);

JUnit 4 Rule

@Rule
	public StubRunnerRule rule = new StubRunnerRule()
			.downloadStub("com.example","artifact-id", "0.0.1")
			.repoRoot("git://[email protected]:spring-cloud-samples/spring-cloud-contract-nodejs-contracts-git.git")
			.stubsMode(StubRunnerProperties.StubsMode.REMOTE);

JUnit 5 Extension

@RegisterExtension
	public StubRunnerExtension stubRunnerExtension = new StubRunnerExtension()
			.downloadStub("com.example","artifact-id", "0.0.1")
			.repoRoot("git://[email protected]:spring-cloud-samples/spring-cloud-contract-nodejs-contracts-git.git")
			.stubsMode(StubRunnerProperties.StubsMode.REMOTE);

Setting up the Producer

By default, the Spring Cloud Contract Plugin uses Rest Assured’s MockMvc setup for the generated tests. Since non-Spring applications do not use MockMvc, you can change the testMode to EXPLICIT to send a real request to an application bound at a specific port.

In this example, we use a framework called Javalin to start a non-Spring HTTP server.

Assume that we have the following application:

import io.javalin.Javalin;

public class DemoApplication {

	public static void main(String[] args) {
		new DemoApplication().run(7000);
	}

	public Javalin start(int port) {
		return Javalin.create().start(port);
	}

	public Javalin registerGet(Javalin app) {
		return app.get("/", ctx -> ctx.result("Hello World"));
	}

	public Javalin run(int port) {
		return registerGet(start(port));
	}

}

Given that application, we can set up the plugin to use the EXPLICIT mode (that is, to send out requests to a real port), as follows:

Maven

<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
	<configuration>
		<baseClassForTests>com.example.demo.BaseClass</baseClassForTests>
		<!-- This will setup the EXPLICIT mode for the tests -->
		<testMode>EXPLICIT</testMode>
	</configuration>
</plugin>

Gradle

contracts {
	// This will setup the EXPLICIT mode for the tests
	testMode = "EXPLICIT"
	baseClassForTests = "com.example.demo.BaseClass"
}

The base class might resemble the following:

import io.javalin.Javalin;
import io.restassured.RestAssured;
import org.junit.After;
import org.junit.Before;
import org.springframework.cloud.test.TestSocketUtils;

public class BaseClass {

	Javalin app;

	@Before
	public void setup() {
		// pick a random port
		int port = TestSocketUtils.findAvailableTcpPort();
		// start the application at a random port
		this.app = start(port);
		// tell Rest Assured where the started application is
		RestAssured.baseURI = "http://localhost:" + port;
	}

	@After
	public void close() {
		// stop the server after each test
		this.app.stop();
	}

	private Javalin start(int port) {
		// reuse the production logic to start a server
		return new DemoApplication().run(port);
	}
}

With such a setup:

We have set up the Spring Cloud Contract plugin to use the EXPLICIT mode to send real requests instead of mocked ones.
We have defined a base class that:
- Starts the HTTP server on a random port for each test.
- Sets Rest Assured to send requests to that port.
- Closes the HTTP server after each test.