The Importance of Being Tested

Transcript

1. Roberto Orgiu | Senior Android Engineer @ NYTimes | @_tiwiz

   The importance of being tested

2. What is testing about?

3. Correctness Functioning

4. Is everything testable?

5. class Repository { private val dep = Dependency( ) fun

   fetch() = dep.getData( ) }

6. class Repository ( private val dep: Dependenc y ) {

   fun fetch() = dep.getData( ) }

7. What should I test?

8. Test the logic, not the code. Fabio Collini (probably?)

9. fun testCode() { repository.fetch( ) verify(mockDependency).getData( ) }

10. fun testLogic() { val actualResult = repository.fetch( ) verify(actualResult )

    .isEqualTo(expectedResult ) }

11. Was that unit testing?

12. Was that unit testing? Is unit testing enough?

13. cwti.link/twitch

14. What about integration testing?

15. What about integration testing? integration tests validate the collaboration and

    interaction of a group of units.

16. My take on integration testing

17. My take on integration testing •No Android deps •Test fl

    ow from start to end •Use Robolectric

18. class RootFragment : Fragment() { lateinit var repository: Repositor y

    lateinit var view: Vie w fun onResume() { val response = repository.fetchThings( ) view.bindResults(response ) } }

19. class IntegrationTest { private val mock = TestDouble(Service() ) private

    val testFragment = RootFragment( ) fun integrationTest() { run(testFragment).verify( ) } } androidTest

20. What about Network?

21. What about network? Network is unreliable

22. What about network? • Retro fi t + OkHttp +

    MockWebServer • Ktor + MockEngine

23. val retrofit = Retrofit.Builder( ) .baseUrl("https://api.github.com/" ) .build( ) This

    should come from the outside!

24. val retrofit = Retrofit.Builder( ) .baseUrl(url ) .build( )

25. val server = MockWebServer( ) server.enqueue ( MockResponse().setBody("hello, world!" )

    ) server.start( ) val url = server.url( )

26. HttpClient(Android) { install(Logging) { … } install(JsonFeature) { … }

    } This should come from the outside!

27. val mockEngine = MockEngine { request - > respond (

    content = ByteReadChannel(content) , status = HttpStatusCode.OK , headers = headersOf(ContentType, type ) ) }

28. What about UI testing?

29. What about UI testing?

30. @get:Rule var activityScenarioRule = activityScenarioRule<MyActivity>( ) @Tes t fun changeText()

    { onView(withId(startViewId) ) .perform ( typeText(MESSAGE) , closeSoftKeyboard( ) ) onView(withId(buttonViewId) ) .perform(click() ) onView(withId(targetView) ) .check(matches(withText(MESSAGE)) ) }
31. None
32. None

33. @Composabl e fun SimpleUI() { var clicks by remember {

    mutableStateOf(0) } Column { Button ( onClick = { clicks++ } ) { Text(text = "Click me" ) } if (clicks > 0) { Text(text = "$clicks" ) } } }

34. @get:Rul e val composeTestRule = createComposeRule( ) @Tes t fun

    verify_initial_case() { composeTestRule.setContent { SimpleUI( ) } composeTestRule.onNodeWithTag("clicks" ) .assertDoesNotExist( ) }

35. @get:Rul e val composeTestRule = createComposeRule( ) @Tes t fun

    verify_last_case() { composeTestRule.setContent { SimpleUI( ) } composeTestRule.onNodeWithText("Click me" ) .performClick( ) with(composeTestRule.onNodeWithTag("clicks")) { assertIsDisplayed( ) assertTextEquals("1" ) } }

36. How can I start testing?

37. Roberto Orgiu | Senior Android Engineer @ NYTimes | @_tiwiz

    Thanks for listening. Q&A Time