Testable Android Architecture (Part 2)

We have so many testing tools for Android now including JUnit, Mockito, Robolectric, and Espresso. But how can you design your application to leverage each one most effectively? This talk introduces a modified version of Model View Presenter (MVP) to help organize your code to be more flexible, maintainable, and testable.

The first half of this talk will recap my presentation from Droidcon NYC 2016. The second half will explore advanced use cases, in-depth code samples, and audience Q&A.

Transcript

1. Testable Android Architecture (Part 2) 15 Nov 2016 / Chuck Greb
2. Clean code Software Craftsmanship
3. Art is anything you can do well. Anything you can do with Quality. “ ” - Robert M. Pirsig
5. → MVC Model View Controller → MVP Model View Presenter → MVVM Model View ViewModel Clean Architecture Design patterns
6. Building your first app
7. Activity
8. Activity Activity Lifecycle System Services
9. Activity EditText Button Activity Lifecycle System Services
10. Activity EditText Button Web Service Storage AsyncTask Activity Lifecycle System Services
11. Fragment Activity EditText Button Web Service Storage AsyncTask Activity Lifecycle System Services Fragment Fragment Lifecycle
12. Fragment Activity EditText Button Web Service Storage AsyncTask Activity Lifecycle System Services Fragment Fragment Lifecycle User Input Input Validation
13. Fragment Activity Web Service Storage AsyncTask Activity Lifecycle System Services Fragment Fragment Lifecycle User Input setRetainInstance(true) EditText Button Input Validation
14. Fragment Activity Web Service Storage AsyncTask Activity Lifecycle System Services Fragment Fragment Lifecycle User Input setRetainInstance(true) Intent Parcelable Extras EditText Button Input Validation
15. Web Service Storage Activity Fragment Fragment AsyncTask setRetainInstance(true) Activity Lifecycle Fragment Lifecycle System Services User Input Intent Activity Instrumentation TestCase2 Parcelable Extras EditText Button Input Validation
17. There has to be a better way
18. Activity Logic
19. Activity Logic Data
20. Activity Logic Data View
21. View (Activity) Controller (Logic) Model (Data) View
22. View (Activity) Presenter (Logic) Model (Data) View
23. View (Activity) ViewModel (Logic) Model (Data) View
24. - Phil Karlton There are only two hard problems in computer science: cache invalidation and naming things “ ”
25. Clean Architecture Model View Presenter Controller MVP(C)
26. Controller (Activity) Presenter (Logic) Model (Data) View
27. Activity Presenter (Logic) Model (Data) View Controller
28. Web Service Storage Activity Activity Lifecycle System Services User Input Presenter View Model Controller Button EditText Thread Input Validation start()
29. Web Service Storage Activity Activity Lifecycle System Services User Input Presenter View Model Controller Button EditText Input Validation Thread start()
30. Testings Models & Presenters JUnit + Mockito
31. Mock Service Mock Storage Test Controller Presenter Model Controller JUnit TestRunner Runnable run()
32. A test is not a unit test if: → It talks to the database → It communicates across the network → It touches the file system → It can't run at the same time as any of your other unit tests → You have to do special things to your environment (such as editing config files) to run it. Michael Feathers, 2005 A Set of Unit Test Rules
33. Testing Activities & Views Robolectric
34. Activity Robolectric TestRunner Robolectric Runtime Environment Simulated Input Stub Presenter View Button EditText Input Validation
35. Demo App https://github.com/ecgreb/mvpc
36. Q & A
37. What is the best way to manage presenter scope or lifecycle? “ ”
38. → Global singleton → Scoped singleton → View State Manager Q & A What is the best way to manage presenter scope or lifecycle?
39. Web Service Storage Activity Activity Lifecycle System Services User Input Presenter View Model Controller Button EditText Thread Input Validation start()
40. Web Service Storage Activity Activity Lifecycle System Services User Input Presenter View Model Controller Button EditText Thread Input Validation start() ViewState Manager (VSM)
41. Can a view have its own presenter? “ ”
42. → True Model-View-Presenter → One presenter instance per view Q & A Can a view have its own presenter?
43. View Presenter Activity Activity Lifecycle System Services User Input Main Presenter View Controller Button EditText Input Validation Model
44. How do you communicate between multiple presenters? “ ”
45. → Pass the message “around the horn” → Event bus Q & A How do you communicate between multiple presenters?
46. Search View Search Presenter Main Activity Main Presenter Navigation View Navigation Presenter
47. Search View Search Presenter Main Activity Main Presenter Navigation View Navigation Presenter Event Bus
48. Eraser Map
51. → Choose an architecture appropriate to your use case → Write tests that work in concert with your architecture → Don’t be overly dogmatic Conclusion So which architecture and testing strategy should I use for my app?
52. Start where you are