Integration testing with TestСontainers-Go

Transcript

1. Integration testing with TestСontainers-Go Nikolay Kuznetsov GopherCon Europe 18 Jun

   2020 @nikolayk812

2. 2 unit tests passed, 0 integration tests

3. Basic integration test

4. Getting a database for testing • Local database • In-memory

   mock • Docker!

5. Docker advantages • 100% compatible databases • Same version as

   production • Empty DB state

6. Integration testing with Docker

7. Easy-peasy! docker run -d -p 5432:5432 postgres:12.1

8. • Host port conflicts • Not ready сontainer / service

   • Resource leak (the container keeps running) • Stale data (if reusing the same container) What could go wrong?

9. Solving some issues

10. None

11. Docker API docs.docker.com/engine/api/latest

12. Exec example

13. None

14. TestContainers-Go github.com/testcontainers/testcontainers-go • Docker Go client under the hood •

    Host port randomization • Containers clean up at the test shutdown • Readiness waiting strategies

15. As simple as pgContainer, err := tc.GenericContainer(ctx, tc.GenericContainerRequest{ ContainerRequest: tc.ContainerRequest{

    Image: "postgres:12.1", ExposedPorts: []string{"5432/tcp"}, }, })

16. Host port randomization • API to get a host port:

    • Prevents port conflicts • Enables parallel builds port, err := pgContainer.MappedPort(ctx, "5432/tcp")

17. Containers cleanup: Ryuk github.com/testcontainers/moby-ryuk • Ryuk kills containers (networks, volumes)

    by labels • TC assigns labels to started containers • TC keeps a connection to Ryuk open • Ryuk acts when the connection is terminated

18. Waiting strategies • Host port • HTTP • SQL •

    Logs • Custom • Multi

19. Host port waiting strategy • Impl checks both from outside

    and inside container • Default (customizable) timeout is 60 seconds tc.ContainerRequest{ Image: "postgres:12.1", ExposedPorts: []string{"5432/tcp"}, WaitingFor: wait.ForListeningPort("5432/tcp"), },

20. HTTP waiting strategy WaitingFor: wait.ForHTTP("/health"). WithPort("8080/tcp"). WithStatusCodeMatcher( func(status int) bool

    { return status == http.StatusOK }),

21. Takeaways • testcontainers.org • Balance between flexibility, speed and features

    • Great for integration tests • Possible to use for end-to-end tests

22. Thank you! @nikolayk812 nikolayk812