Version: 6.0 🚧

Setup

The Kotest test framework is supported on JVM, Javascript and Native. To enable Kotest for multiple platforms, combine the steps for the individual platforms as detailed in the following tabs.

caution

The KMP support in Kotest 6.0 has changed from the previous versions. There is no longer a compiler plugi but a simplified setup. Please see the rest of this page for details on how to configure Kotest for KMP in Kotest 6.0 and later.

JVM/Gradle
Kotlin/JS
Kotlin/WasmJS
Kotlin/Native
Android

tip

A working project with JVM support can be found here: https://github.com/kotest/kotest-examples

Kotest on the JVM has two ways for running tests. One uses the Kotest gradle plugin, which provides detailed test output in the console, and a rich experience in Intellij (in conjuction with the Intellij Kotest plugin). The other option uses the JUnit Platform gradle plugin which is ubiquitous in the JVM ecosystem but lacks some features of the Kotest gradle plugin.

To use the Kotest gradle plugin, add the following to your build.gradle.kts file:

plugins {
   id("io.kotest") version "$version"
}

Add the following dependency to your build:

dependencies {
   testImplementation("io.kotest:kotest-framework-engine:$version")
}

And then execute the kotest task in gradle, or run tests directly from the IDE.

To use the JUnit Platform plugin, add the following to your build.gradle.kts file:

tasks.withType<Test>().configureEach {
   useJUnitPlatform()
}

Add the following dependency to your build:

dependencies {
   testImplementation("io.kotest:kotest-runner-junit5:$version")
}

And then execute the test task in gradle, or run tests directly from the IDE.

tip

A working JS project can be found here: https://github.com/kotest/kotest-examples

Add the Kotest gradle plugin and Google KSP plugin to to your build.

For example:

plugins {
   id("io.kotest") version "$version"
   id("com.google.devtools.ksp") version "2.2.0-2.0.2"
}

Add the engine dependency to your commonTest or jsTest source set:

kotlin {
   js()
   sourceSets {
      jsTest {
         dependencies {
            implementation("io.kotest:kotest-framework-engine:$version")
         }
      }
   }
}

Tests can be placed in either commonTest or jsTest. Run your tests using the jsKotest gradle task.

note

The JS test engine is feature limited when compared to the JVM test engine. The major restriction is that annotation based configuration will not work as Kotlin does not expose annotations at runtime to JS code.

tip

A working WasmJS project can be found here: https://github.com/kotest/kotest-examples

Add the Kotest gradle plugin and Google KSP plugin to to your build.

For example:

plugins {
   id("io.kotest") version "$version"
   id("com.google.devtools.ksp") version "2.2.0-2.0.2"
}

Add the engine dependency to your commonTest or wasmJsTest source set:

kotlin {
   wasmJs()
   sourceSets {
      wasmJsTest {
         dependencies {
            implementation("io.kotest:kotest-framework-engine:$version")
         }
      }
   }
}

Tests can be placed in either commonTest or wasmJsTest. Run your tests using the wasmJsKotest gradle task.

note

The WasmJS test engine is feature limited when compared to the JVM test engine. The major restriction is that annotation based configuration will not work as Kotlin does not expose annotations at runtime to Wasm code.

tip

A working native project with linux, windows and macos configured, with unit and data driven test examples, can be found here: https://github.com/kotest/kotest-examples

Add the Kotest gradle plugin and Google KSP plugin to to your build.

For example:

plugins {
  id("io.kotest") version "$version
  id("com.google.devtools.ksp") version "2.2.0-2.0.2"
}

Add the engine dependency to your commonTest, nativeTest or platform specific sourceset:

kotlin {
   linuxX64() // add any supported native target
   sourceSets {
      nativeTest {
         dependencies {
            implementation("io.kotest:kotest-framework-engine:$version")
         }
      }
   }
}

Tests can be placed in either commonTest or a specific native sourceset. Run your tests using the kotest tasks that mirror the target names, for example linuxX86Kotest.

note

The native test engine is feature limited when compared to the JVM test engine. The major restriction is that annotation based configuration will not work as Kotlin does not expose annotations at runtime to native code.

info

Currently, only Unit tests are supported in Kotest. The following steps enable Kotest to be used for unit tests, where the Android framework is not needed or is mocked that usually reside in the src/test folder of your module.

Kotest on Android uses the JUnit Platform gradle plugin. This requires configuring the android test options block in your build file and then adding the Kotest junit5 runner dependency.

android.testOptions {
   unitTests.all {
      it.useJUnitPlatform()
   }
}

dependencies {
   testImplementation 'io.kotest:kotest-runner-junit5:version'
}

tip

A working Android project with unit and data driven test examples, can be found here: https://github.com/kotest/kotest-examples