State of JUnit 5 in Android

Transcript

1. Aung Kyaw Paing Senior Consultant @ thoughtworks | GDE Android aungkyawpaing.dev State of Junit 5 in Android
3. “JUnit was born on a flight from Zurich to the 1997 OOPSLA in Atlanta. Kent was flying with Erich Gamma, and what else were two geeks to do on a long flight but program?” - Martin Fowler
4. In fact, the original SUnit framework only has only three small classes and twelve methods!
5. “Never in the field of software development have so many owed so much to so few lines of code” - Martin Fowler
7. Junit 4 - Annotations were introduced - Method name no longer require you to start with “test” prefix - Runners are introduced
10. Runners - Can only have one single runner for each test class - You can’t have Parameterized test if you’re using other class runner like AndroidTestRunner - We want to separate runner, reporting and so on into different interfaces
11. Execution model - Requires all test to be known prior to execution - Prevent dynamic creation of test cases during execution
12. Toolchain - IDEs and build tools are tightly coupled to JUnit internals - Some tools use reflection to access internal APIs - In short, JUnit 4 was not made to be extensible across multiple tools
13. The vision - Decouple test execution and reporting from test definition and provisioning - Rethinking JUnit’s extensibility - Make use of Java 8 features
14. 2017 JUnit 5 become stable
15. What’s in JUnit 5 for me?
16. Cleaner Reporting
17. Kotlin Friendly @Test fun `should return invalid when text is empty`() { ... }
18. Multiple Assertions Assertions.assertAll( "Assertions subset of variable", { Assertions.assertEquals(actual.name, "Vincent")}, { Assertions.assertEquals(actual.age, 28)}, { Assertions.assertTrue(actual.isSpeaker)}, )
19. Asserting Exceptions val exception = assertThrows( IOException::class.java ) { functionThatThrow() } assertEquals(exception.message, "Error reading file")
20. Assumptions @Test fun shouldGetFromDatabase() { // Abort test if watch is not connected Assumptions.assumeTrue(isConnectedToWearOS())) // Execute test }
21. Inner Tests class ProfileScreenTest { @InnerTest @DisplayName("when user is logged in") inner class WhenUserLoggedInTests { // ... test functions } @InnerTest @DisplayName("when user is logged out") inner class WhenUserLoggedOutTests { // ... test functions } }
22. Tagging @Test @Tag("Fast") fun fastTestThatCanRunLocally() @Test @Tag("Slow") fun slowTestThatWeRunOnCI()
23. Tagging task slowTest(type: Test) { useJUnitPlatform { includeTags 'slow' } } // .gradlew slowTest
24. Conditional tests @Test @EnabledOnOs({OS.MAC}) fun shouldRunOnlyOnMac() { // ... }
25. Repeated tests @RepeatedTest(value = 3, failureThreshold = 1) fun flakyTests() { // ... }
26. Parameterized tests @ParameterizedTest @ValueSource( strings = ["", "abcd", "abc213"] ) fun validateShouldReturnFalse(input: String) { Assertions.assertFalse(validatePhoneNumber(input)) }
27. Dynamic Tests @TestFactory fun apiContractTests(): List<DynamicTest> { val apiDataFile : List<String> = readAssetDir("api_tests") apiDataFile.map { metadata -> dynamicTest("API Test: ${metadata.endpoint}") { // PING API } } }
28. JUnit 4 Backwards compatibility
29. class JUnit4Test { @Before fun setUp() { } @After fun tearDown() {} @Test fun test() { Assert.assertEquals(true, true) } } Similar structures class JUnit5Test { @BeforeEach fun setUp() { } @AfterEach fun tearDown() {} @Test fun test() { Assertions.assertEquals(true, true) } }
30. @get:Rule val composeTestRule = createComposeRule() Rule —> Extensions
31. Rule —> Extensions @JvmField @RegisterExtension val extension = createComposeExtension()
32. implementation ("org.junit.vintage:junit-vintage-engine") Or just run Junit4!
33. JUnit 5 on Android
34. JUnit 5 on Android - Google has no plan to officially support for Junit 5 as it will require a lot of resources
35. JUnit 5 on Android - Google has no plan to officially support for Junit 5 as it will require a lot of resources - However we have community maintained plugin!
36. plugins { id("de.mannodermaus.android-junit5") version "1.11.2.0" }
37. plugins { id("de.mannodermaus.android-junit5") version "1.11.2.0" } dependencies { // (Required) Writing and executing Unit Tests on the JUnit Platform testImplementation("org.junit.jupiter:junit-jupiter-api:5.11.2") testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.11.2") // (Optional) If you need "Parameterized Tests" testImplementation("org.junit.jupiter:junit-jupiter-params:5.11.2") // (Optional) If you also have JUnit 4-based tests testImplementation("junit:junit:4.13.2") testRuntimeOnly("org.junit.vintage:junit-vintage-engine:5.11.2") }
38. Instrumentation Tests dependencies { androidTestImplementation("org.junit.jupiter:junit-jupiter-api:5.11.2") }
39. Instrumentation Tests class MyActivityTest { @JvmField @RegisterExtension val scenarioExtension = ActivityScenarioExtension.launch<MyActivity>() @Test fun myTest() { val scenario = scenarioExtension.scenario // Do something with the scenario here... } }
40. Compose Tests dependencies { androidTestImplementation("de.mannodermaus.junit5:android-test-compose") }
41. Compose Tests class ComposeTest { @JvmField @RegisterExtension val extension = createComposeExtension() @Test fun composeTest() = extension.use { setContent { Text("Hello") } onNodeWithText("Hello").assertIsDisplayed() } }
42. Roboletric Android JUnit4 - No official support yet (#3477) - Is part of Google Summer of Code 2024 (Pitch Deck)
43. Roboletric Android JUnit4 - No official support yet (#3477) - Is part of Google Summer of Code 2024 (Pitch Deck) - But we have a community plugin!
44. Roboletric plugins { id("tech.apter.junit5.jupiter.robolectric-extension-gradle-plugin") version "0.8.0" } @ExtendWith(RobolectricExtension::class) class RobolectricTest { @Test fun `JUnit5 with robolectric`() { assertNotNull(RuntimeEnvironment.getApplication()) } }
45. Gradle Managed Device Gradle Managed Device is the recommended way to run instrumentation tests as it interacts with actual system API and it’s fast unlike running on actual emulators or real devices. It is also scalable with Firebase Test Lab!
46. testOptions { managedDevices { localDevices { create("pixel") { // Use device profiles you typically see in Android Studio. device = "Pixel 2" // Use only API levels 27 and higher. apiLevel = 30 // To include Google services, use "google". systemImageSource = "aosp" } } } }
47. Unit Tests Features Supported? Instrumentation Compose Dagger Hilt HiltAndroidRule has no equivalent extension as it requires annotating with HiltAndroidTest to generate code Robolectric Limited support
48. My Recommendations Unit Tests Instrumentation Tests UI Tests E2E Junit 5 Junit 5 running on Gradle Managed Device Maestro, Appium etc
49. So what can you do?
50. What can I do? - +1 in the issue tracker and voice out if you have any https://issuetracker.google.com/issues/127100532 - Thumbs up on Robolectric open issue https://github.com/robolectric/robolectric/issues/3477 - Star android-junit5 library https://github.com/mannodermaus/android-junit5 - Start using Junit5 in your app
51. Aung Kyaw Paing Senior Consultant @ thoughtworks | GDE Android aungkyawpaing.dev State of Junit 5 in Android