You can open this sample inside an IDE using the IntelliJ native importer or Eclipse Buildship.

This sample shows how to test Java projects with JUnit5 in Gradle.

For applications:

application/build.gradle
plugins {
    id 'application'
}

dependencies {
    implementation project(':utilities')
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.6.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
}

application {
    mainClass = 'org.gradle.sample.app.Main'
}

test {
    useJUnitPlatform()
}
application/build.gradle.kts
plugins {
    application
}

dependencies {
    implementation(project(":utilities"))
    testImplementation("org.junit.jupiter:junit-jupiter-api:5.6.1")
    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
}

application {
    mainClass.set("org.gradle.sample.app.Main")
}

tasks.named<Test>("test") {
    useJUnitPlatform()
}

For libraries:

list/build.gradle
plugins {
    id 'java-library'
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.6.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
}

test {
    useJUnitPlatform()
}
list/build.gradle.kts
plugins {
    `java-library`
}

dependencies {
    testImplementation("org.junit.jupiter:junit-jupiter-api:5.6.1")
    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
}

tasks.named<Test>("test") {
    useJUnitPlatform()
}

Running the tests:

$ ./gradlew test

BUILD SUCCESSFUL
5 actionable tasks: 5 executed

For more information, see Testing in Java project chapter.

You can also generate this project locally using gradle init.