Integration testing with TestСontainers-Go

GopherCon Europe 2020 - Lightning talk

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
11. Docker API docs.docker.com/engine/api/latest
12. Exec example
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