TestContainers is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

1. Prague, 19-20 October 2017
TestContainers
@antonarhipov
Integration testing without the hassle

3. Why integration testing?

10. 1. # of tests per time unit

11. 1. # of tests per time unit
2. Complex setup

13. 1. Reproducible environment

14. 1. Reproducible environment
2. Both for development and CI

15. 1. Reproducible environment
2. Both for development and CI
3. Isolated

16. 1. Reproducible environment
2. Both for development and CI
3. Isolated
4. As real as possible

17. 1. Reproducible environment
2. Both for development and CI
3. Isolated
4. As real as possible
5. Cross-platform

18. 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

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);

28. TestContainers
https://github.com/testcontainers/testcontainers-java

29. Microservices!11
REST service
Java, Spring Boot
Redis & PostgreSQL
Calls to some other application

30. @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();

31. @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!

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();
External
dependencies

34. 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)));
}
}

35. 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)));
}
}

36. MockServerClient client = …
client.when(
HttpRequest.request("/analytics/issues/" +
project.projectId + "/app").withMethod("GET"),
Times.unlimited())
.respond(singleIssueResponse());

39. How to test Java agents?

40. https://github.com/bsideup/javaagent-boilerplate

41. https://www.testcontainers.org
https://twitter.com/testcontainers
https://github.com/testcontainers
https://testcontainers.slack.com

42. anton@zeroturnaround.com
@antonarhipov
slideshare.net/arhan