TestEngine with ID 'junit-jupiter' failed to discover tests

Hi,

I try to implement instrumented unit tests. I work with Android Studio 3.0.1

My top Level build.gradle:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext.kotlin_version = '1.2.21'

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
        classpath "de.mannodermaus.gradle.plugins:android-junit5:1.0.30"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

My app-level build.gradle:

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: "de.mannodermaus.android-junit5"

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "com.todo.app"
        minSdkVersion 26
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    testOptions {
        // Configuration closure added by the plugin;
        // all configurable parameters related to JUnit 5 can be found here
        junitPlatform {
            // The JUnit Jupiter dependency version to use
            jupiterVersion "5.0.3"

            // The JUnit Vintage Engine dependency version to use
            vintageVersion "4.12.2"

            // Options related to running unit tests with JUnit 5.
            unitTests {
                // Whether or not JUnit 5 test tasks should be affected by
                // JVM Arguments, System Properties & Environment Variables
                // declared through "unitTests.all" closures
                applyDefaultTestOptions true
            }

            // Options related to running instrumented tests with JUnit 5.
            // This is an incubating feature which utilizes the backwards-compatibility
            // of the JUnit Platform in order to enhance the default Test Instrumentation Runner
            // with new power. However, because of their experimental nature and steep minSdkVersion requirement,
            // they are turned off by default. If you choose to enable them, you also have to declare
            // the library dependency in your androidTest scope. Please refer to the "Setup"
            // section for more details.
            instrumentationTests {
                enabled true

                // The Android-Instrumentation-Test dependency version to use
                version "0.1.1"
            }
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:design:26.1.0'
    implementation 'com.android.support:cardview-v7:26.1.0'
    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    testCompile 'org.junit.jupiter:junit-jupiter-api:5.0.3'
    testCompile "org.mockito:mockito-core:2.13.0"

    // (Required) Writing and executing Unit Tests on the JUnit Platform.
    testImplementation junit5.unitTests()

    // (Optional) If you need "Parameterized Tests".
    testImplementation junit5.parameterized()

    // (Optional) For running tests inside Android Studio 3.x
    testCompileOnly junit5.unitTestsRuntime()

    androidTestImplementation junit5.instrumentationTests()
}

repositories {
    mavenCentral()
}

apply plugin: 'kotlin-android-extensions'

Under src/androidTest/java/com.myapp.app/ExempleInstrumentedTest my test:

package com.todo.app

import org.junit.jupiter.api.Assertions.*
import org.junit.jupiter.api.Test

class ExampleInstrumentedTest {

    @Test
    fun test() {

        // Read the data.
        assertEquals(true, true, "test")
    }
}

When I try to launch this test I got this error (on android studio):

févr. 01, 2018 7:48:50 PM org.junit.platform.launcher.core.DefaultLauncher handleThrowable
AVERTISSEMENT: TestEngine with ID 'junit-jupiter' failed to discover tests
org.junit.platform.commons.util.PreconditionViolationException: Could not load class with name: com.todo.app.ExampleInstrumentedTest

and

févr. 01, 2018 7:48:50 PM org.junit.platform.launcher.core.DefaultLauncher handleThrowable
AVERTISSEMENT: TestEngine with ID 'junit-vintage' failed to discover tests
org.junit.platform.commons.util.PreconditionViolationException: Could not load class with name: com.todo.app.ExampleInstrumentedTest

Process finished with exit code 0
Empty test suite.

What is the problem ?

[progonkpa]

As you may now Android Studio is basically the same IDE as IntelliJ. I ran into this issue with IntelliJ Community Edition. I had the newest version of JUnit in my dependencies (5.4.1) which turned out to be an issue.

The error went away after switching to JUnit 5.3.2. I discoverd this version number by removing the JUnit dependencies and letting IntelliJ resolve the import statements.

[Leander250]

I got the same problem using Spring Boot with the Gradle Spring Dependency Management plugin. This solved my issue without downgrading the Version to 5.3.2: https://stackoverflow.com/questions/54598484/gradle-5-junit-bom-and-spring-boot-incorrect-versions/54605523#54605523