Reactive Extensions for Java

Predictable state container for Kotlin apps

Using Mockito with Kotlin.

JUnit Jupiter is the API for writing tests using JUnit 5.

Kotlin Test Multiplatform library

A Specification Framework for the JVM

Spek TestEngine for the JUnit Platform

Runner and annotations for configuring and executing tests on the JUnit Platform in a JUnit environment.

Mockito mock objects library core API and implementation