![Tip #3 [1/3] - TestSubscriber
● Subscriber with additional test methods
● Part of RxJava](https://image.slidesharecdn.com/bestpracticesforunittestingrxjava-161109121345/85/Best-practices-for-unit-testing-RxJava-25-320.jpg)
![Tip #3 [2/3] - TestScheduler](https://image.slidesharecdn.com/bestpracticesforunittestingrxjava-161109121345/85/Best-practices-for-unit-testing-RxJava-32-320.jpg)
![Tip #3 [3/3] - TestSubject
● Enables us to queue events with a delay
○ onNext(T, delayMs)
○ onCompleted(delayMs)
○ onError(Throwable, delayMs)](https://image.slidesharecdn.com/bestpracticesforunittestingrxjava-161109121345/85/Best-practices-for-unit-testing-RxJava-34-320.jpg)
Best practices for unit testing RxJava
- 1. Best practices for unit testing RxJava Simon Perčič, senior Android developer Tuesday, November 8th, 2016 @ 18:00
- 2. RxJava? ● Useful for combining, transforming, manipulating streams of data ● How to unit test?
- 3. What to unit test? ● Observables - composition of operators ● Code that uses Rx (e.g. presenters)
- 4. Let’s set an example
- 5. What will we test?
- 6. What will we test? DataManager methods:
- 8. Tip #1 Separate data providers
- 9. Test skeleton 1/3 mocked subject of testing
- 12. Test examples* * not best practices
- 13. Wrong test #1 Works. → But only if getPlanets() is run on the immediate thread
- 14. Wrong test #1 Works. → But only if getPlanets() is run on the immediate thread
- 15. Not immediate thread Runs on another thread!
- 16. Wrong test #1 - on another thread Fails. → getPlanets() switches thread, Assert happens “too soon”
- 17. Wrong test #2 - blocking Works. → it waits for the getPlanets() single to complete.
- 18. Wrong test #2 - countdown Blocks here
- 20. Tip #2 Single / Observable transformer Network thread
- 21. Tip #2 - in manager Compose with scheduler transformer
- 22. Tip #2 - in test No op transformation.
- 23. Tip #3 (the big one)* * best practices
- 24. Built-in classes ● TestSubscriber ● TestScheduler ● TestSubject
- 25. Tip #3 [1/3] - TestSubscriber ● Subscriber with additional test methods ● Part of RxJava
- 27. ● Blocking ○ awaitTerminalEvent() TestSubscriber methods Will block
- 28. ● Assertions ○ Completion ■ assertCompleted() / assertNotCompleted() ■ assertTerminalEvent() / assertNoTerminalEvent() TestSubscriber methods
- 29. ● Assertions ○ Errors ■ assertNoErrors() ■ assertError(Class / Throwable) TestSubscriber methods
- 30. ● Assertions ○ Values ■ assertNoValues() ■ assertValueCount(int) ■ assertValue(T) / assertValues(T…) TestSubscriber methods
- 31. ● Get values ○ Values ■ List<T> getOnNextEvents() ○ Errors ■ List<Throwable> getOnErrorEvents() TestSubscriber methods
- 32. Tip #3 [2/3] - TestScheduler
- 33. ● Time “manipulation” ○ Advance time ■ advanceTimeBy(long, TimeUnit) ■ advanceTimeTo (long, TimeUnit) ○ Force trigger ■ triggerActions() TestScheduler methods
- 34. Tip #3 [3/3] - TestSubject ● Enables us to queue events with a delay ○ onNext(T, delayMs) ○ onCompleted(delayMs) ○ onError(Throwable, delayMs)
- 37. ● Use RxJava ● Make your code unit-testable ● Be aware of threading ● Use built-in testing utils Recap