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
   

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2. Hello, I'm Victoria!
   • Android Engineer at Buffer
   • Author at RayWenderlich.com
   • Hedgehog and cat owner
   

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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.
   

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4. 1.
   What is TDD
   Test-Driven Development
   basics
   

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5. What to test?
   ▪ Do test code that:
   ▪ Contains logic
   ▪ Is fragile
   ▪ Will change
   

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6. What to not test?
   ▪ Don't test code that:
   ▪ Is not yours
   ▪ Is generated
   ▪ Is throwaway
   

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7. What is TDD
   ▪ Write a failing test
   ▪ Write code to make it
   pass
   ▪ Refactor
   

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8. Why use TDD?
   ▪ Write intentionally
   ▪ Automatically document
   ▪ Keep maintainable code
   ▪ Have confidence in your
   code
   ▪ Develop faster
   ▪ Higher test coverage
   

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9. 2.
   The Pyramid
   How many tests should I have?
   

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10. Testing Pyramid
    ▪ 10% UI Tests
    ▪ 20% Integration
    Tests
    ▪ 70% Unit Tests
    

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11. Unit Tests
    ▪ Fast
    ▪ Focused
    ▪ Mock dependencies
    

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12. Integration Tests
    ▪ Slower
    ▪ Test parts working
    together
    

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13. UI Tests
    ▪ Slowest
    ▪ Running full app
    

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14. 3.
    Tools
    What can you use for testing?
    

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15. Architecture
    ▪ Important for
    testability
    ▪ Design with tests in
    mind
    

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16. Mockito
    ▪ "Tasty mocking
    framework for unit
    tests in Java
    ▪ Make "fake"
    dependencies
    

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17. Robolectric
    ▪ "Robolectric is a
    framework that brings
    fast and reliable unit
    tests to Android."
    ▪ Android sandbox, off
    device
    

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18. Espresso
    ▪ UI Testing
    ▪ "Use Espresso to
    write concise,
    beautiful, and reliable
    Android UI tests."
    

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19. MockWebServer
    ▪ Stub network
    responses
    ▪ "A scriptable web
    server for testing
    HTTP clients."
    

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20. 4.
    Legacy apps
    What if it's not a new app?
    

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21. Understand your
    boundaries
    ▪ Get familiar with
    architecture
    ▪ Think about
    constraints
    

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22. High-Level Tests
    ▪ Usually Espresso
    tests
    ▪ Mock out network
    

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23. “
    ...break the app up into components
    and refactor things a component at a
    time.
    

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24. Refactoring
    ▪ Make code more
    testable
    ▪ Helped by high-level
    tests
    

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25. Refactor Tests
    ▪ As code changes,
    your tests will too
    

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26. Handling Test Data
    ▪ Tests also need to be
    maintained
    

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27. TDD is hard
    ▪ It takes practice
    ▪ You'll make mistakes
    

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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.
    

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29. Thanks!
    @TTGonda
    VictoriaGonda.com
    

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