JavaOne 2017 - TestContainers: integration testing without the hassle
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This document introduces TestContainers, an open source tool for running Docker containers as part of integration tests. It discusses why integration testing is important for reproducibility, isolation, and realism. TestContainers allows setting up Docker containers programmatically and automatically cleaning them up after tests complete. It supports starting individual containers, Docker Compose environments, and custom container types. Examples are given for testing services that depend on databases, caches, and external APIs using TestContainers without complex test environment configuration. The document also describes how to use TestContainers to test Java agents by modifying bytecode at runtime within a container during tests.
![public static void premain(String args, Instrumentation instrumentation) {
instrumentation.addTransformer(new ClassFileTransformer() {
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
ProtectionDomain protectionDomain, byte[] classfileBuffer)
throws IllegalClassFormatException {
if ("spark/webserver/JettyHandler".equals(className)) {
try {
ClassPool cp = new ClassPool();
cp.appendClassPath(new LoaderClassPath(loader));
CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer));
CtMethod ctMethod = ct.getDeclaredMethod("doHandle");
ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }");
return ct.toBytecode();
} catch (Throwable e) {
e.printStackTrace();
}
}
return classfileBuffer;
}
});
}](https://image.slidesharecdn.com/javaonesf2017-testcontainers-171005065133/85/JavaOne-2017-TestContainers-integration-testing-without-the-hassle-42-320.jpg)
![public static void premain(String args, Instrumentation instrumentation) {
instrumentation.addTransformer(new ClassFileTransformer() {
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
ProtectionDomain protectionDomain, byte[] classfileBuffer)
throws IllegalClassFormatException {
if ("spark/webserver/JettyHandler".equals(className)) {
try {
ClassPool cp = new ClassPool();
cp.appendClassPath(new LoaderClassPath(loader));
CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer));
CtMethod ctMethod = ct.getDeclaredMethod("doHandle");
ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }");
return ct.toBytecode();
} catch (Throwable e) {
e.printStackTrace();
}
}
return classfileBuffer;
}
});
}](https://image.slidesharecdn.com/javaonesf2017-testcontainers-171005065133/85/JavaOne-2017-TestContainers-integration-testing-without-the-hassle-43-320.jpg)
![public static void premain(String args, Instrumentation instrumentation) {
instrumentation.addTransformer(new ClassFileTransformer() {
@Override
public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined,
ProtectionDomain protectionDomain, byte[] classfileBuffer)
throws IllegalClassFormatException {
if ("spark/webserver/JettyHandler".equals(className)) {
try {
ClassPool cp = new ClassPool();
cp.appendClassPath(new LoaderClassPath(loader));
CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer));
CtMethod ctMethod = ct.getDeclaredMethod("doHandle");
ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }");
return ct.toBytecode();
} catch (Throwable e) {
e.printStackTrace();
}
}
return classfileBuffer;
}
});
}](https://image.slidesharecdn.com/javaonesf2017-testcontainers-171005065133/85/JavaOne-2017-TestContainers-integration-testing-without-the-hassle-44-320.jpg)
JavaOne 2017 - TestContainers: integration testing without the hassle
- 1. TestContainers Integration testing without the hassle @antonarhipov
- 9. 1. # of tests per time unit
- 10. 1. # of tests per time unit 2. Complex setup
- 13. 1. Reproducible environment 2. Both for development and CI
- 14. 1. Reproducible environment 2. Both for development and CI 3. Isolated
- 15. 1. Reproducible environment 2. Both for development and CI 3. Isolated 4. As real as possible
- 16. 1. Reproducible environment 2. Both for development and CI 3. Isolated 4. As real as possible 5. Cross-platform
- 17. 1. Reproducible environment 2. Both for development and CI 3. Isolated 4. As real as possible 5. Cross-platform 6. Easy to set up, use & maintain
- 19. Docker Compose FTW! redis: image: redis ports: - "6379:6379" postgres: image: postgres ports: - "5432:5432" elasticsearch: image: elasticsearch:5.0.0 ports: - "9200:9200"
- 24. TestContainers to the rescue!
- 25. How does it work? https://github.com/docker-java/docker-java Docker environment discovery Will start docker machine if it’s not started yet Containers cleanup on JVM shutdown
- 26. GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379);
- 27. GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); PostgreSQLContainer postgreSQLContainer = new PostgreSQLContainer("postgres:9.6.2") .withUsername(POSTGRES_USERNAME) .withPassword(POSTGRES_PASSWORD);
- 29. Docker Compose? - Yes! public static DockerComposeContainer env = new DockerComposeContainer( new File("src/test/resources/compose-test.yml")) .withExposedService("redis_1", REDIS_PORT);
- 30. Docker Compose? - Yes! public static DockerComposeContainer env = new DockerComposeContainer( new File("src/test/resources/compose-test.yml")) .withExposedService("redis_1", REDIS_PORT); String url = env.getServiceHost("redis_1", REDIS_PORT); Integer port = env.getServicePort("redis_1", REDIS_PORT); Jedis jedis = new Jedis(url, port);
- 31. Microservices!11 REST service Java, Spring Boot Redis & PostgreSQL Calls some other micro-services
- 32. @RunWith(SpringJUnit4ClassRunner.class) @SpringBootTest(classes = DemoApplication.class, webEnvironment = WebEnvironment.RANDOM_PORT) @ContextConfiguration(initializers = AbstractIntegrationTest.Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer();
- 33. @RunWith(SpringJUnit4ClassRunner.class) @SpringBootTest(classes = DemoApplication.class, webEnvironment = WebEnvironment.RANDOM_PORT) @ContextConfiguration(initializers = AbstractIntegrationTest.Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer(); Still using all the Spring goodies!
- 34. @RunWith(SpringJUnit4ClassRunner.class) @SpringBootTest(classes = DemoApplication.class, webEnvironment = WebEnvironment.RANDOM_PORT) @ContextConfiguration(initializers = AbstractIntegrationTest.Initializer.class) public abstract class AbstractIntegrationTest { @ClassRule public static PostgreSQLContainer postgreSql = new PostgreSQLContainer(); @ClassRule public static GenericContainer redis = new GenericContainer("redis:3.0.6") .withExposedPorts(6379); @ClassRule public static MockServerContainer mockServer = new MockServerContainer(); External dependencies
- 36. public class MockServerContainer<SELF extends MockServerContainer<SELF>> extends GenericContainer<SELF> { public MockServerContainer() { super("jamesdbloom/mockserver:latest"); addExposedPorts(8080); } private MockServerClient client; @Override protected void containerIsStarted(InspectContainerResponse containerInfo) { super.containerIsStarted(containerInfo); client = new MockServerClient(getContainerIpAddress(), getMappedPort(getExposedPorts().get(0))); } }
- 37. public class MockServerContainer<SELF extends MockServerContainer<SELF>> extends GenericContainer<SELF> { public MockServerContainer() { super("jamesdbloom/mockserver:latest"); addExposedPorts(8080); } private MockServerClient client; @Override protected void containerIsStarted(InspectContainerResponse containerInfo) { super.containerIsStarted(containerInfo); client = new MockServerClient(getContainerIpAddress(), getMappedPort(getExposedPorts().get(0))); } }
- 38. MockServerClient client = … client.when( HttpRequest.request("/analytics/issues/" + project.projectId + "/app").withMethod("GET"), Times.unlimited()) .respond(singleIssueResponse());
- 41. How to test Java agents?
- 42. public static void premain(String args, Instrumentation instrumentation) { instrumentation.addTransformer(new ClassFileTransformer() { @Override public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { if ("spark/webserver/JettyHandler".equals(className)) { try { ClassPool cp = new ClassPool(); cp.appendClassPath(new LoaderClassPath(loader)); CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer)); CtMethod ctMethod = ct.getDeclaredMethod("doHandle"); ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }"); return ct.toBytecode(); } catch (Throwable e) { e.printStackTrace(); } } return classfileBuffer; } }); }
- 43. public static void premain(String args, Instrumentation instrumentation) { instrumentation.addTransformer(new ClassFileTransformer() { @Override public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { if ("spark/webserver/JettyHandler".equals(className)) { try { ClassPool cp = new ClassPool(); cp.appendClassPath(new LoaderClassPath(loader)); CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer)); CtMethod ctMethod = ct.getDeclaredMethod("doHandle"); ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }"); return ct.toBytecode(); } catch (Throwable e) { e.printStackTrace(); } } return classfileBuffer; } }); }
- 44. public static void premain(String args, Instrumentation instrumentation) { instrumentation.addTransformer(new ClassFileTransformer() { @Override public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { if ("spark/webserver/JettyHandler".equals(className)) { try { ClassPool cp = new ClassPool(); cp.appendClassPath(new LoaderClassPath(loader)); CtClass ct = cp.makeClass(new ByteArrayInputStream(classfileBuffer)); CtMethod ctMethod = ct.getDeclaredMethod("doHandle"); ctMethod.insertBefore("{ $4.setHeader("X-My-Super-Header", "header value"); }"); return ct.toBytecode(); } catch (Throwable e) { e.printStackTrace(); } } return classfileBuffer; } }); }
- 45. public class AgentTest { @ClassRule public static BasicTestApp app = new BasicTestApp(); @Test public void testIt() throws Exception { Response response = app.getClient().getHello(); System.out.println("Got response:n" + response); assertThat(response.headers().get("X-My-Super-Header")) .isNotNull() .hasSize(1) .containsExactly("header value"); } }
- 46. public class AgentTest { @ClassRule public static BasicTestApp app = new BasicTestApp(); @Test public void testIt() throws Exception { Response response = app.getClient().getHello(); System.out.println("Got response:n" + response); assertThat(response.headers().get("X-My-Super-Header")) .isNotNull() .hasSize(1) .containsExactly("header value"); } } A custom container
- 47. public class AgentTest { @ClassRule public static BasicTestApp app = new BasicTestApp(); @Test public void testIt() throws Exception { Response response = app.getClient().getHello(); System.out.println("Got response:n" + response); assertThat(response.headers().get("X-My-Super-Header")) .isNotNull() .hasSize(1) .containsExactly("header value"); } } Verify, if the new behaviour is there