Testing frameworks for Android

The presentation will tell which frameworks you can use to test your application starting from local unit tests and end with functional testing.
Tools that are described are JUnit, Mockito, PowerMock, Hamcrest, Espresso, Robolectric.

Transcript

1. Testing frameworks Pavel Shchahelski Android Developer Slimware
3. Tests? • Take time • Adding code to code base • Slow down
4. Write Tests • Rapid feedback on failures • Easier to fix on early stage • Safety net • Free to refactor, clean up, optimize • Backbone of software
5. @LargeTest @MediumTest @SmallTest Type of tests
8. Android test code • project sources • ${module}/src/main/java
9. Android test code • project sources • ${module}/src/main/java • instrumentation tests • ${module}/src/androidTest/java
10. Android test code • project sources • ${module}/src/main/java • instrumentation tests • ${module}/src/androidTest/java • unit test • ${module}/src/test/java
11. Unit Tests
12. Unit Tests • Run on JVM • Modified android.jar • gradle test • ${module}/build/reports/tests/${variant}/index.html
13. Unit Tests android { ... testOptions { unitTests.returnDefaultValues = true } }
14. JUnit
15. JUnit • Used to test pure java/kotlin • Does not provide any mocks or Android APIs • The main part of both unit and instrumentation tests
16. class ExampleUnitTest { @Test fun addition_isCorrect() { assertEquals(4, 2 + 2) } } JUnit
17. Assertions • assertEquals • assertNotEquals • assertTrue • assertFalse • assertNull • assertNotNull • assertThat
18. Annotations • @BeforeClass • @Rule • @Before • @Test • @After • @AfterClass • @Ignore https://cdn-images-1.medium.com/max/1000/1*Lp8XW7Flz91G8GoISm9NKA.jpeg
19. Annotations @RunWith(JUnit4::class) class ExampleUnitTest { private lateinit var myClass: MyClass private lateinit var map: MutableMap<String, String> @Before fun setUp() { myClass = MyClass() map = mutableMapOf() } @Test fun addition_isCorrect() { assertEquals(4, 2 + 2) } @After fun tearDown() { map.clear() } }
20. Runners @RunWith(JUnit4::class) class ExampleUnitTest 1. BlockJUnit4ClassRunner 2. GuiceJUnitRunner 3. MockitoJUnitRunner 4. SpringJUnit4ClassRunner 5. . . .
22. http://www.vogella.com/tutorials/Mockito/article.html https://github.com/mockito/mockito
23. Mockito • Very readable syntax • Annotation support • Large stackoverflow community • Most popular Java/Android mocking framework
24. Mockito 1. ${project}/build.gradle
 
 repositories { jcenter() } 2. ${module}/build.gradle
 dependencies { 
 ...
 
 testCompile "org.mockito:mockito-core:2.+" 
 }
25. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
26. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
27. Creating a mock private lateinit var postExecution: PostExecutionThread @Before fun setUp() { postExecution = Mockito.mock(PostExecutionThread::class.java) } https://examples.javacodegeeks.com/core-java/mockito/mockito-initmocks-example/
28. Test doubles • Dummy • Stub • Spy • Mock
29. Test doubles • Dummy • Stub • Spy • Mock
30. Dummy class Messenger(private val templateEngine: TemplateEngine, private val mailServer: MailServer) { fun sendMessage(client: Client, template: Template) { val msgContent: String = templateEngine.prepare(template, client) mailServer.send(client.getEmail(), msgContent) } } @Test fun testDummy(){ val template = mock(Template::class.java) sut.sendMessage(client, template) }
31. Test doubles • Dummy • Stub • Spy • Mock
32. Stub class Messenger(private val templateEngine: TemplateEngine, private val mailServer: MailServer) { fun sendMessage(client: Client, template: Template) { val msgContent: String = templateEngine.prepare(template, client) mailServer.send(client.getEmail(), msgContent) } } @Test fun testStub(){ val templateEngine = mock(TemplateEngine::class.java) val sut = Messenger(mailServer, templateEngine) `when`(templateEngine.prepare(template, client)) .thenReturn(MSG_CONTENT) sut.sendMessage(client, template) }
33. Test doubles • Dummy • Stub • Spy • Mock
34. Spy class Messenger(private val templateEngine: TemplateEngine, private val mailServer: MailServer) { fun sendMessage(client: Client, template: Template) { val msgContent: String = templateEngine.prepare(template, client) mailServer.send(client.getEmail(), msgContent) } } @Test fun testSpy(){ val mailServer = mock(MailServer::class.java) val sut = Messenger(mailServer, templateEngine) sut.sendMessage(client, template) verify(mailServer).send("some@email.com", msgContent) }
35. Test doubles • Dummy • Stub • Spy • Mock
37. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
38. Verifying private lateinit var sut: GetInstalledAppsUseCase private lateinit var repository: CachedAppRepository @Before fun setUp() { repository = mock() thread = mock() postExecution = mock() sut = GetInstalledAppsUseCase(repository, thread, postExecution) } @Test fun `test use case is built correctly`() { sut.buildUseCaseObservable(None) verify(repository).getInstalledApps() }
39. Verifying private lateinit var sut: GetInstalledAppsUseCase private lateinit var repository: CachedAppRepository @Before fun setUp() { repository = mock() thread = mock() postExecution = mock() sut = GetInstalledAppsUseCase(repository, thread, postExecution) } @Test fun `test use case is built correctly`() { sut.buildUseCaseObservable(None) verify(repository, ).getInstalledApps() } times(1) atLeast(1) atLeastOnce(1) atMost(1) only() never()
40. Verifying private lateinit var sut: GetInstalledAppsUseCase private lateinit var repository: CachedAppRepository @Before fun setUp() { repository = mock() thread = mock() postExecution = mock() sut = GetInstalledAppsUseCase(repository, thread, postExecution) } @Test fun `test use case is built correctly`() { sut.buildUseCaseObservable(None) verify(repository).saveInstalledApps( ) } any(T::class.java) anyInt() anyString() anyOrNull() anyArray(Array<T>::class.java)
41. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
42. Stubbing @Test fun stubMethod() { val user = User(webService, USER_ID, PASSWORD) `when`(webService.isOffline()).thenReturn(true) user.login() verify(webService, never()).login() }
43. Stubbing @Test fun stubMethod() { val user = User(webService, USER_ID, PASSWORD) `when`(webService.isOffline()).thenReturn(true) user.login() verify(webService, never()).login() }
44. Stubbing @Test fun stubMethod() { val user = User(webService, USER_ID, PASSWORD) `when`(webService.isOffline()).thenReturn(true) user.login() verify(webService, never()).login() } https://www.javacodegeeks.com/2013/02/testing-expected-exceptions-with-junit-rules.html
45. Stubbing • Normal syntax
 
 `when`(webService.isOffline()).thenReturn(true) • Alternative syntax
 
 doReturn(true).`when`(webService).isOffline() • BDD
 
 given(webService.isOffline()).willReturn(true)

46. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
47. Limitations • Unable to mock • static methods • private methods • hashcode() and equals()
48. Mockito • Creating a mock • Verifying • Stubbing methods • Limitations • Capturing
50. https://github.com/powermock/powermock
51. PowerMock • Can mock static methods • Can be used together with Mockito
52. PowerMock @RunWith(PowerMockRunner::class) @PrepareForTest(Static::class) class YourTestCase { @Test fun testMethodThatCallsStaticMethod() { // mock all the static methods in a class called "Static" PowerMockito.mockStatic(Static::class.java) // use Mockito to set up your expectation Mockito.`when`(Static.firstStaticMethod(param)).thenReturn(value) // execute your test classCallStaticMethodObj.execute() // Always use PowerMockito.verifyStatic(Class) first // to start verifying behavior PowerMockito.verifyStatic(Static::class.java, Mockito.times(2)) // IMPORTANT: Call the static method you want to verify Static.firstStaticMethod(param) } }
53. Hamcrest https://code.google.com/archive/p/hamcrest/wikis/Tutorial.wiki
55. What about Android?
56. Android Testing Framework
57. Android Testing Framework • AndroidJUnitRunner • JUnit4 Rules • Espresso • UiAutomator
58. AndroidJUnitRunner • JUnit4 support • Collect tests • Execute tests • Report results
59. JUnit4 Rules • ActivityTestRule • IntentsTestRule • ServiceTestRule • ProviderTestRule • GrantPermissionRule
60. https://developer.android.com/training/testing/espresso/index.html
61. Espresso 1. ${module}/build.gradle
 dependencies { 
 ...
 
 androidTestImplementation 'com.android.support.test:runner:1.0.1' androidTestImplementation ‘com.android.support.test.espresso:espresso-core:3.0.1'
 } 2. ${module}/build.gradle
 android.defaultConfig { 
 
 testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" }
62. Espresso @Test fun test(){ onView(ViewMatchers) .perform(ViewAction) .check(ViewAssertion) }
63. View @Test fun test(){ onView(withId(R.id.action_bar)) .perform(click()) .check(matches(isDisplayed())) }
65. View @RunWith(AndroidJUnit4::class) class LoginActivityTest { @Rule @JvmField val loginActivityRule = ActivityTestRule<LoginActivity>(LoginActivity::class.java) @Test fun shouldVerifyEmptyPassword(){ onView(withId(R.id.email)) .perform(typeText("Alex"), closeSoftKeyboard()) onView(withId(R.id.login)) .perform(click()) onView(withId(R.id.password)) .check(matches(withError(`is`("Please enter a password")))) } }
66. View fun withError(expected: Matcher<String>): Matcher<View> { return object : TypeSafeMatcher<View>() { override fun matchesSafely(item: View): Boolean { return if (item is TextInputLayout) { expected.matches(item.error.toString()) } else false } override fun describeTo(description: Description) { description.appendText("with error message: ") description.appendText(expected.toString()) } } }
67. Lists @Test fun test(){ onData(ObjectMatcher) .DataOptions .perform(ViewAction) .check(ViewAssertion) }
68. RecyclerView • actionOnHolderItem • actionOnItem • actionOnItemAtPosition • scrollTo • scrollToHolder • scrollToPosition
69. RecyclerView @Test fun test(){ onView(withId(R.id.recycler_view)) .perform(actionOnItemAtPosition(3, click())) }
70. Synchronization • Message Queue • AsyncTask • Idling Resources
71. http://robolectric.org/
72. Robolectric • Run Android tests on JVM • Tests are fast • Include Android classes in tests
73. Robolectric ${module}/build.gradle
 dependencies { 
 ...
 
 testImplementation ‘org.robolectric:robolectric:3.6.1’ }
74. Robolectric @RunWith(RobolectricTestRunner::class) class MainActivityTest { @Test fun testTitleColor(){ val activity = Robolectric.setupActivity(MainActivity::class) assertTrue(activity.getTitle().toString().equals("Main Activity")) } }
75. Robolectric @RunWith(RobolectricTestRunner::class) /** * Calls the same lifecycle methods on the Activity called by Android the first time the Activity is created. * * @return Activity controller instance. */ public ActivityController<T> setup() { return create().start().postCreate(null).resume().visible(); }
76. Robolectric @RunWith(RobolectricTestRunner::class) class MyActivityTest { @Test @Throws(Exception::class) fun clickingButton_shouldChangeResultsViewText() { val activity = Robolectric.setupActivity(MyActivity::class.java) val button = activity.findViewById(R.id.button) as Button val results = activity.findViewById(R.id.results) as TextView button.performClick() assertThat(results.getText().toString()) .isEqualTo("Robolectric Rocks!") } }
77. Resources • https://developer.android.com/training/testing/index.html • https://www.youtube.com/watch?v=pK7W5npkhho&feature=youtu.be • https://www.youtube.com/watch?v=AlxMGxs2QnM&feature=youtu.be • https://www.youtube.com/watch?v=DJDBl0vURD4 • https://dzone.com/articles/understanding-junits-runner • http://www.vogella.com/tutorials/AndroidTesting/article.html • http://myhexaville.com/2018/01/01/android-local-tests-robolectric/
78. Resources • http://www.vogella.com/tutorials/Robolectric/article.html • http://www.vogella.com/tutorials/Mockito/article.html • https://www.linkedin.com/pulse/mockito-2x-over-powermock-migration-tips- tricks-top-ten-hazem-saleh/ • https://android.jlelse.eu/building-a-shazam-clone-part-5-discover-song-feature- building-android-apps-series-a70f7c3a9795 • https://android.jlelse.eu/animated-custom-view-driven-by-tests-5f082190acd6 • https://fernandocejas.com/2017/02/03/android-testing-with-kotlin/
79. Resources • https://proandroiddev.com/testing-user-interface-of-android-app-with- architecture-components-data-binding-and-dagger-2-5d15c3779807 • https://academy.realm.io/posts/360-andev-2017-inaki-villar-advanced-expresso/ • https://www.philosophicalhacker.com/post/psa-dont-use-esprsso-idling- resources-like-this/ • https://android.jlelse.eu/helping-androiddev-to-mock-tests-in-kotlin- ab3be5204559#.8l72082k2 • https://dzone.com/articles/7-popular-unit-test-naming • https://www.youtube.com/watch?v=AlxMGxs2QnM&feature=youtu.be
80. Resources • https://engineering.21buttons.com/mocking-kotlin-classes-with-mockito-the-fast- way-631824edd5ba • Growing Object-Oriented Software, Guided by Tests by Steve Freeman, Nat Pryce (Book) • Tomek Kaczanowski - Practical Unit Testing with JUnit and Mockito (Book) • XUnit Test Patterns Refactoring Test Code (Book)