TDD for Android

Overview of base principle Test-Driven Development. How to use TDD for Android project. Tips for creating well tested Android projects.

Project:
https://github.com/AlexZhukovich/TemperatureConverterTDD

Blog:
http://alexzh.com

Transcript

1. TDD for Android
2. Why do we test? •Testing ensure the Quality of the product; •Tests help improve design code; •Tests check that code works;
3. Observations • Huge activities / fragments • Hard to add a new feature • Hard to test • Many apps tested in manual way • Fragmentation • Slow Android tests • Required device • Robolectric • Espresso • etc
4. Bad vs Good tests @Test public void test1() { mPresenter.attachView(null); mPresenter.convertTemperature(); mPresenter.detachView(); verify(mView, never()).getInputValue(); verify(mView, never()).getFromTemperatureUnit(); verify(mView, never()).getToTemperatureUnit(); verify(mView, never()).setOutputValue(anyDouble()); when(mTemperatureFactory.getTemperatureConverter()) .thenReturn(mConverter); doNothing().when(mConverter).convertData(any(InputData.class)); mPresenter.attachView(mView); mPresenter.convertTemperature(); mPresenter.detachView(); verify(mEventBus).register(any()); verify(mView).displayProgress(); verify(mView, times(1)).getInputValue(); verify(mView, times(1)).getFromTemperatureUnit(); verify(mView, times(1)).getToTemperatureUnit(); verify(mEventBus).unregister(any()); } @Test public void shouldVerifyConvertDataSuccessful () { mPresenter.attachView(mView); mPresenter.convertTemperature(); mPresenter.detachView(); verify(mEventBus).register(any()); ... } @Test public void shouldVerifyConvertDataWithNullView() { mPresenter.attachView(null); mPresenter.convertTemperature(); mPresenter.detachView(); verify(mView, never()).getInputValue(); ... } Don’t Do
5. Bad vs Good UI tests @Test public void shouldVerifyGravity() { View view = ...; assertEquals(Gravity.START, view.getForegroundGravity()); ... } @Test public void shouldVerifyOrderCoffee() { onView(withId(R.id.name_edit)) .perform(typeText("User"), closeSoftKeyboard()); onView(withId(R.id.pay)) .perform(click()); onView(withId(R.id.detail_text)) .check(matches(isDisplayed())); } Don’t Do
6. Value
7. What is Test Driven Development (TDD) Green Refactor Red
8. Code separations Android App Core Acceptance tests Unit tests
9. Model-View-Presenter View Presenter Model
10. Application overview Web service Local
11. Application overview Presenter Use case Repository Web service Local
12. Recommendation for setting up the device / emulator One small recommendation for avoiding flakiness is turning off animation on real or virtual devices. • Window animation scale • Transition animation scale • Animator duration scale • Settings / Developer Options/
13. Hamcrest library
14. Hamcrest + Espresso public static Matcher<Object> withToolbarTitle(final Matcher<String> textMatcher) { return new BoundedMatcher<Object, Toolbar>(Toolbar.class) { @Override public boolean matchesSafely(Toolbar toolbar) { return textMatcher.matches(toolbar.getTitle()); } @Override public void describeTo(Description description) { description.appendText("with toolbar title: ") textMatcher.describeTo(description); } }; } onView(withId(R.id.toolbar)) .check(matches(withToolbarTitle( is (TITLE)))); startsWith endsWith ...
15. UI test @RunWith(AndroidJUnit4.class) public class TemperatureConverterActivityTest { @Test public void shouldVerifyConvertingFromCelsiusToFahrenheit() { onView(withId(R.id.inputView)) .perform(typeText(String.valueOf(CELSIUS_VALUE)), closeSoftKeyboard()); setTemperatureUnit(R.id.inputTemperatureSpinner, CELSIUS_STR); setTemperatureUnit(R.id.outputTemperatureSpinner, FAHRENHEIT_STR); onView(withId(R.id.convertButton)) .perform(click()); onView(withId(R.id.outputView)) .check(matches(isDisplayed())); onView(withId(R.id.outputView)) .check(matches(withText(getOutputString(FAHRENHEIT_VALUE)))); } }
16. Presenter test @RunWith(MockitoJUnitRunner.class) public class TemperatureConverterPresenterTest { @Mock TemperatureConverterView mView; … private TemperatureConverterPresenter mPresenter; @Test public void shouldVerifyConvertDataSuccessfulWithCorrectView() { mPresenter.attachView(mView); mPresenter.convertTemperature(); mPresenter.detachView(); verify(mEventBus).register(any()); ... } }
17. Asynchronous calls using Mockito (Retrofit2) @RunWith(MockitoJUnitRunner.class) public class OnlineConverterTemperatureTest { private OnlineConverterTemperature mConverter; @Mock EventBus mEventBus; @Mock TemperatureConverterApiService mApiService; @Mock Call<ConvertedResult> mCall; @Mock ResponseBody mResponseBody; @Captor ArgumentCaptor<Callback<ConvertedResult>> argumentCapture; @Test public void shouldGetConvertedResult() { when(mApiService.getConvertedData(anyString(), anyString(), anyString())) .thenReturn(mCall); Response<ConvertedResult> response = Response.success(mConvertedResult); mConverter.convertData(mInputData); verify(mCall).enqueue(argumentCapture.capture()); argumentCapture.getValue().onResponse(null, response); verify(mEventBus).post(new TemperatureConvertedSuccessful(mConvertedResult)); } }
18. Testing system stuff • Notifications; • Press hardware buttons; • Interacting with any applications. UI Automator
19. Continuous Integration (CIRCLE CI) circle.yml
20. Testing tips
21. Focus on App behaviour
22. Use available stuff
23. Use hamcrest library
24. Do not copy your code between tests
25. Launch directly desire screen
26. Many small tests are better that big ones
27. Test your code, not using libraries
28. Test-Driven Development is NOT a silver bullet
29. Thank you 1. Getting Started with Testing (Android) https://developer.android.com/training/testing/start/index.html 2. Espresso https://google.github.io/android-testing-support-library/docs/espresso/ 3. Ui Automator https://developer.android.com/training/testing/ui-testing/uiautomator-testing.html 4. Robolectric http://robolectric.org/ 5. Project https://github.com/AlexZhukovich/TemperatureConverterTDD 6. Blog http://alexzh.com/ @Alex_Zhukovich