TestContainers - integration testing without the hassle

Presented @ TopConf Tallinn

Transcript

1. TestContainers Integration testing without the hassle Sergei @bsideup Egorov
2. Integration testing Why it matters?
3. Verify how your software product will behave in real-world conditions
4. Isolated from other system components to avoid false negatives
5. Real: databases, file systems, network interfaces, …
6. Grey box testing - we know some inner details, but mostly use public APIs
8. Unit testing • Simulation tests are green, yay! • Everything is mocked • DB is written by others, why should I test it?
9. Integration testing https://commons.wikimedia.org/wiki/File:Cd4007.jpg • Jeez, how did it passed the Unit testing? • Is it a smoke? @#$%! YES IT IS! • Who knew that 100w soldering gun was a bit too powerful for it?
10. System testing https://commons.wikimedia.org/wiki/File:UART_8250_Microchip.jpg • Takes a lot of time to solder • “Oh no, the power bus is too far away from my microchip!” • Interference between the components
11. Production
12. Integration testing Real-world, but isolated testing Spot the issues before the real environment Can be run during the development You have to start real databases Should be cross-platform Slower than Unit testing Pros Cons
13. Obvious solution
15. Abstraction layer
16. CI friendly
17. Cross-platform
18. Docker Compose FTW! redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"

19. But…
20. No ports randomization redis:
 image: redis
 ports:
 - "6379:6379"
 postgres:
 image: postgres
 ports:
 - "5432:5432"
 elasticsearch:
 image: elasticsearch:5.0.0
 ports:
 - "9200:9200"

21. Fighting with Docker environment
22. There is no place like
23. There is no place like Except Docker Machine
24. Can we improve that?
26. Remove the database
27. Remove the database
29. As simple as PostgreSQLContainer postgresql = new PostgreSQLContainer()
 
 GenericContainer redis = new GenericContainer("redis:3")
 .withExposedPorts(6379)
30. TestContainers • https://github.com/testcontainers/testcontainers-java • OSS project by Richard North, supported by ZeroTurnaround • Declarative Docker Java API wrapper • JUnit rules, can be used with other frameworks like TestNG, Cucumber, etc…
31. How it works • Wraps https://github.com/docker-java/docker-java • Docker environment discovery • Will start docker-machine if it’s not started yet • Docker for Mac support • Containers cleanup on JVM shutdown
32. Use case #1: testing of microservices • REST service • Java, Spring Boot • Redis and PostgreSQL • Calls some other micro-services
33. Demo
34. Use case #2: Docker as Selenium driver • Selenium/Selenide tests • No need to install Chrome/Firefox/etc • CI friendly
35. Demo
36. Use case #3: Java agent testing • Test different Java versions • Simplify I/O testing • The actual reason why ZeroTurnaround decided to use TestContainers :)
37. Demo