Android Test-Driven Development

Test-Driven Development (TDD) is a software development process where you write failing tests before writing the code to make it pass. This can be a common practice in some technology circles, but we’ve seen slow adoption on Android. Because it’s not embedded in the Android culture, it can be hard to learn how to get started with TDD. In this talk, we’ll go over the basics of TDD, how you can apply it at varying levels in an Android architecture, and what steps to take if you’re working with legacy code. You should walk away from this talk with the tools you need to get started exploring practicing TDD on your own.

Transcript

1. Android Test-Driven Development Victoria Gonda
2. Hello, I'm Victoria! • Android Engineer at Buffer • Author at RayWenderlich.com • Hedgehog and cat owner
3. Android Test-Driven Development by Tutorials A book that teaches you to write sustainable, testable apps, as well as to apply testing strategies to legacy projects via Espresso and UI tests, code coverage and refactoring.
4. 1. What is TDD Test-Driven Development basics
5. What to test? ▪ Do test code that: ▪ Contains logic ▪ Is fragile ▪ Will change
6. What to not test? ▪ Don't test code that: ▪ Is not yours ▪ Is generated ▪ Is throwaway
7. What is TDD ▪ Write a failing test ▪ Write code to make it pass ▪ Refactor
8. Why use TDD? ▪ Write intentionally ▪ Automatically document ▪ Keep maintainable code ▪ Have confidence in your code ▪ Develop faster ▪ Higher test coverage
9. 2. The Pyramid How many tests should I have?
10. Testing Pyramid ▪ 10% UI Tests ▪ 20% Integration Tests ▪ 70% Unit Tests
11. Unit Tests ▪ Fast ▪ Focused ▪ Mock dependencies
12. Integration Tests ▪ Slower ▪ Test parts working together
13. UI Tests ▪ Slowest ▪ Running full app
14. 3. Tools What can you use for testing?
15. Architecture ▪ Important for testability ▪ Design with tests in mind
16. Mockito ▪ "Tasty mocking framework for unit tests in Java ▪ Make "fake" dependencies
17. Robolectric ▪ "Robolectric is a framework that brings fast and reliable unit tests to Android." ▪ Android sandbox, off device
18. Espresso ▪ UI Testing ▪ "Use Espresso to write concise, beautiful, and reliable Android UI tests."
19. MockWebServer ▪ Stub network responses ▪ "A scriptable web server for testing HTTP clients."
20. 4. Legacy apps What if it's not a new app?
21. Understand your boundaries ▪ Get familiar with architecture ▪ Think about constraints
22. High-Level Tests ▪ Usually Espresso tests ▪ Mock out network
23. “ ...break the app up into components and refactor things a component at a time.
24. Refactoring ▪ Make code more testable ▪ Helped by high-level tests
25. Refactor Tests ▪ As code changes, your tests will too
26. Handling Test Data ▪ Tests also need to be maintained
27. TDD is hard ▪ It takes practice ▪ You'll make mistakes
28. Android Test-Driven Development by Tutorials A book that teaches you to write sustainable, testable apps, as well as to apply testing strategies to legacy projects via Espresso and UI tests, code coverage and refactoring.
29. Thanks! @TTGonda VictoriaGonda.com