Android Unit Testing with Robolectric

Using Robolectric to facilitate Android Unit Testing, presented in Singapore Android Developers meetup http://www.meetup.com/Singapore-Android-Developers/events/194790032/

Transcript

1. Android unit testing with Robolectric Tho Nguyen Senior Android Developer @TradeHero
2. How does Junit work
3. Why Android is hard to do unit testing  Many of classes, methods are final  Lack of interfaces  Non public constructors  Static methods
4. Have you tried?  Google does not want to show you the ugly part: Method bodies are replaced by a RuntimeException
5. What have we tried?  No tests. God blesses us for almost half a year  Painful manual testing  Reproducing same bugs again and AGAIN  New developers join with risk  Integration testing  Slow  Not reliable  No fun  Robolectric  FuN~ 
6. Robolectric  Tests run in JVM, not in DavikVM  No dexing, packaging, installation process. No emulator or device needed  Run on JVM  Fast  Freedom  Can use reflection without worry about performance  Can use big libraries, large jar file: apache common, google libraries like truth, guava.  Fast debugging and possible hot code swapping  Test behavior not implementation
7. Robolectric
8. How does Robolectric work  Shadow Objects  View and resources loading
9. Shadow objects  Shadows back android classes. i.e ShadowImageView backs the ImageView class (Robolectric creates and uses shadow object instead of the real object if possible, look here)  Record state for testing verification  Simplify behaviors Shadow RealObject
10. Custom shadow implementation
11. Using custom shadow  Declaration  Usage
12. View and resources loading  Robolectric parses layout files and build a tree of view objects with shadows  Robolectric also loads strings.xml, colors.xml …  Simulate runtime Android environment.
13. Writing test  Specify that the test needs android instrument.
14. Demo  Source code available at: https://github.com/nguyentruongtho/robomeetup  Writing Robolectric Junit test  Customize RobolectricTestRunner  TestLifecycleApplication  Robolectric & Dependency injection (Dagger)  Customize Robolectric for Maven, Git Submodule
15. Question?  http://www.tradehero.mobi/Careers  Join us, boss robolectric will be watching you   Me  http://twitter.com/thontu  http://github.com/nguyentruongtho  http://linkedin.com/in/nguyentruongtho/  Resources  http://robolectric.org/  http://www.slideshare.net/tylerschultz/robolectric-android-unit- testing-framework