How can I use kotlin.test with an Android project?

Question

When I search for what I wrote on the title the internet is completely full of results about using JUnit, JUnit5, Mockito, TestNG and whatnot.

I went over the official docs and they provide a sample with the JVM.

I went ahead and gave it a try and as soon as I add

test {
    useJUnitPlatform()
}

to my build.gradle another plugin breaks with:

Caused by: org.gradle.internal.metaobject.AbstractDynamicObject$CustomMessageMissingMethodException: Could not find method test() for arguments [build_dufjov4kr7mc23edqwrf6trov$_run_closure1@6a819f87] on project ':app' of type org.gradle.api.Project.

How do I get past that?

Answer 1

That test block seems optional.

Just add the following dependencies:

testImplementation 'junit:junit:4.13.2'
testImplementation 'org.jetbrains.kotlin:kotlin-test'
testImplementation 'org.jetbrains.kotlin:kotlin-test-junit'

Then, in your tests, pick the correct imports, ie. import kotlin.test.assertEquals

Seems like the test block below is NOT necessary.

Answer 2

Please see the Kotlin Docs on how to set-up Jetbrains Kotlin Test JUnit on Intellij using Kotlin DSL.

Using this approach you need to do the following on Android Studio:

Step 1 - Add this line to your dependencies: i.e. inside build.gradle.kts (app-level) file

dependencies { 
...

testImplementation(kotlin("test"))
...

}

Step 2 (Optional)- Add the test task block i.e. inside build.gradle(.kts) (project-level) file:

// Top-level build file where you can add configuration ...

    plugins {
        id("com.android.application") apply false
        ....
    }
    
    // add this block on project-level build.gradle.kts
    tasks.withType<Test> {

        useJUnitPlatform()

    }

You can also try this dependency using the latest Kotlin Version (in Dec. 2023 it was 1.9.10)

testImplementation ("org.jetbrains.kotlin:kotlin-test-junit:1.9.10")

This is what worked out for me.