JUnit 5 for Android testing

Question

How to configure JUnit 5 for Android unit testing? I tried:

testCompile("org.junit.jupiter:junit-jupiter-api:5.0.0")

But it doesn't work, when I run previous the simplest unit test:

@Test
public void addition_isCorrect() throws Exception {
    assertEquals(4, 2 + 2);
}

I get error:

Exception in thread "main" java.lang.NoSuchMethodError: org.junit.platform.commons.util.ReflectionUtils.getDefaultClassLoader()Ljava/lang/ClassLoader;
    at org.junit.platform.launcher.core.ServiceLoaderTestEngineRegistry.loadTestEngines(ServiceLoaderTestEngineRegistry.java:31)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:42)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:36)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

Process finished with exit code 1
Empty test suite.

Answer 1

Refer to this issue and this issue regarding JUnit 5 support on Android.

Add this build script dependency in your top-level build.gradle[.kts] file:

buildscript {
  dependencies {
    classpath("de.mannodermaus.gradle.plugins:android-junit5:1.8.2.1")
  }
}

And add these lines in your app or library build.gradle[.kts] file:

plugins {
  // ...
  id("de.mannodermaus.android-junit5")
}

dependencies {
  // Aggregator dependency on JUnit api, engine, and params
  testImplementation("org.junit.jupiter:junit-jupiter:5.9.1")
  // (Optional) If you also have JUnit 4-based tests
  testImplementation("junit:junit:4.13.2")
  testRuntimeOnly("org.junit.vintage:junit-vintage-engine:5.9.1")
}

You can use the above solution if you are using Android Gradle plugin 3.2.0 or higher and Gradle 4.7 or higher. For more information refer to the plugin GitHub page.

Extended answer

If you want to use JUnit 5 in your instrumented tests (androidTest source set) do the following:

1. Add these dependencies to your app or libray build script:

androidTestImplementation("de.mannodermaus.junit5:android-test-core:1.3.0")
androidTestRuntimeOnly("de.mannodermaus.junit5:android-test-runner:1.3.0")

2. Use ActivityScenarioExtension instead of ActivityScenarioRule in your test classes:

import de.mannodermaus.junit5.ActivityScenarioExtension

class MyActivityTest {

  @JvmField
  @RegisterExtension
  val scenarioExtension = ActivityScenarioExtension.launch<MyActivity>()

  @Test
  fun test1() {
    val scenario = scenarioExtension.scenario
    scenario.moveToState(Lifecycle.State.RESUMED)
    assertThat(scenario.state).isEqualTo(Lifecycle.State.RESUMED)
  }

  @Test
  fun test2(scenario: ActivityScenario<MyActivity>) {
    scenario.moveToState(Lifecycle.State.RESUMED)
    assertThat(scenario.state).isEqualTo(Lifecycle.State.RESUMED)
  }
}

Answer 2

Android Studio is based on IDEA, correct?

Then see this answer here https://stackoverflow.com/a/46161799/1431016 or read directly the user-guide at http://junit.org/junit5/docs/current/user-guide/#running-tests-ide-intellij-idea

Summary:

// Only needed to run tests in an IntelliJ IDEA that bundles an older version
testImplementation("org.junit.platform:junit-platform-launcher:1.0.0")
testImplementation("org.junit.jupiter:junit-jupiter-engine:5.0.0")
testImplementation("org.junit.vintage:junit-vintage-engine:4.12.0")

I didn't try this project yet, but it could help you using JUnit 5 on Android: https://github.com/aurae/android-junit5

Answer 3

USE ALWAYS THE OFFICIAL VERSION

First go to the official documentation of Junit here : https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api you will see all latest version like this

then in your app/gradle add this dependencie :

testImplementation('org.junit.jupiter:junit-jupiter:X.X.X')

where X.X.X is the version you want. For example in my case it was

testImplementation('org.junit.jupiter:junit-jupiter:5.6.0')