TestContainers + JUnit 5 = elegant integration and e2e tests for microservices

Transcript

1. TestContainers + JUnit 5 = elegant integration and e2e tests

   for microservices Nikolay Kuznetsov @nikolayk812 TESTING UNITED Vienna, 7 November 2019

2. About me • Go developer at Zalando Helsinki • Java

   developer at Infobip, DevExperts • C developer at Samsung, Motorola

3. My testing experience • Unit, integration and end-to-end automated tests

   development • Various organizational structures ◦ Separate QA teams ◦ QA engineers in a dev team ◦ No QA teams/engineers at all

4. Key points • Targeting automated testing • Examples and demos

   in Java: TestContainers-Java, JUnit 5, Spring Boot • Principles are language-agnostic

5. Why integration testing?

6. 2 unit tests, 0 integration tests

7. Tests trade-offs

8. None

9. Basic integration test

10. Integration testing evolution • In-memory mocking • Local DBs •

    Vagrant • Docker, Docker Compose • Docker API

11. Docker architecture

12. How to start a container for test? • Shell scripts

    • Maven plugin • Docker Compose • Docker API • MiniKube, Kubernetes

13. Shell scripts

14. Maven plugin github.com/fabric8io/docker-maven-plugin

15. Docker Compose

16. Docker API

17. None

18. TestContainers flavors

19. TestContainers Java • github.com/testcontainers/testcontainers-java • Wraps docker-java library • Docker

    environment autodiscovery • Host port randomization • Containers clean up on JVM shutdown • Readiness waiting strategies

20. As simple as var redis = new GenericContainer("redis:5.0.5") .withExposedPorts(6379); var

    postgres = new PostgreSQLContainer();

21. Docker environment autodiscovery

22. Host port randomization • Prevents port conflicts • Enables parallel

    CI builds • API to get an actual host port

23. Containers cleanup github.com/testcontainers/moby-ryuk

24. Readiness waiting strategies • Host port • HTTP status/body •

    Log message • Docker healthcheck • Combination of above • Custom

25. Demo setup User Service

26. Demo scenario User Service INSERT INTO SELECT FROM

27. Demo github.com/nikolayk812/tu-tc-demo

28. Demo recap • JUnit 5 integration via Extension API ◦

    @TestContainers / @Container • TestContainers Modules ◦ 14 databases ◦ Kafka, MockServer, LocalStack, ToxiProxy, etc

29. JUnit 5 Extensions • Customizable extension points: ◦ Life-cycle phases

    ◦ Parameter resolution ◦ Conditional execution, etc • Extension logic registered with @ExtendsWith

30. github.com/nikolayk812/tu-tc-demo Demo-2: setup User Service

31. Demo-2: scenario User Service POST /users GET /user/<id>

32. Demo-2: Docker network User Service user-alias: 8083 postgres-alias: 5432 localhost:

    32812

33. Demo 2 github.com/nikolayk812/tu-tc-demo

34. Demo-2: recap • Docker network and alias

35. Why end-to-end testing? • Business flows across multiple services •

    Regression, when ◦ + new service ◦ - legacy service

36. Testing/staging deployed cluster Spring Cloud Kubernetes

37. Testing against a deployed cluster • Deploy a new service

    version to the cluster? • Unexpected versions of dependent services • Unexpected database states ◦ Care to clear after the test? • Parallel CI builds?

38. On-demand cluster for E2E tests + Locally and at CI

    machines + Control over dependent services versions - Time to start all containers - Resources: memory and CPU How to do it?

39. Kubernetes for E2E tests?

40. Kubernetes for E2E tests - YAGNI TestContainers + Docker network!

41. E2E test setup User Service Item Service

42. Takeaways • https://testcontainers.org • Balance between flexibility, speed and features

    • Works on Mac, Linux, Windows

43. QUESTIONS ?