Quick introduction to TDD on Android using Robolectric.

1. The Magic of Android Unit Testing
Johny
Urgiles

2. Johny Urgiles
● 3 years @ Amplify
● Android dev for half of that
● Code quality aficionado
● The Lab for Robotics Education

4. Amplify & Test Driven Development
● Write test first
● See it fail
● Write simplest possible solution
● Refactor
● Sleep peacefully at night

5. Finished Product

6. Slow &
Careful

7. Slow &
Careful

8. Slow &
Careful
Fast &
Risky

9. Slow &
Careful
Fast &
Risky

11. Android & TDD
● Android Instrumentation Unit Testing
○ Pretty slow by unit test standards
○ We still have to maintain a
separate infrastructure for
tablet <-> tablet interaction

12. Android on JUnit

13. Stubbin

14. It’s Raining Runtime Exceptions

15. Robolectric 2.0
JVM
Robolectric
JUnit Test

17. Robolectric
● Mimics Android functionality
● 2.0 includes Android code (4.2.1 rc1)
● Provides view into Android internals
● Extendable with ‘Shadows’

18. Robolectric @ Amplify
● 4500 unit tests across our Android Apps
● Most in a single repo: 3751
○ Runs in 6.5 minutes (Macbook Pro)
○ Migration to Robolectric 2.0 took a part-time dev
about 3 weeks
○ Worth it
● Devs run unit tests in IntelliJ

19. Code Time

20. More Unit Testing @ Amplify
● RoboGuice
○ Based on Google Guice
○ Dependency injection for Android
● Mockito
○ Standard Java Mock library
● Android FEST
○ Assertion library by Square