kotlin-testing

Comprehensive Kotlin testing patterns for writing reliable, maintainable tests following TDD methodology with Kotest and MockK. The following sections contain detailed, runnable examples for each testing pattern: DO: DON'T: Remember : Tests are documentation. They show how your Kotlin code is meant to be used. Use Kotest's expressive matchers to make tests readable and MockK for clean mocking of dependencies. - Writing new Kotlin functions or classes - Adding test coverage to existing Kotlin code - Implementing property-based tests - Following TDD workflow in Kotlin projects - Configuring Kover for code coverage - Identify target code — Find the function, class, or module to test - Write a Kotest spec — Choose a spec style (StringSpec, FunSpec, BehaviorSpec) matching the test scope - Mock dependencies — Use MockK to isolate the unit under test - Run tests (RED) — Verify the test fails with the expected error - Implement code (GREEN) — Write minimal code to pass the test - Refactor — Improve the implementation while keeping tests green - Check coverage — Run ./gradlew koverHtmlReport and verify 80%+ coverage - Kotest specs — StringSpec, FunSpec, BehaviorSpec, DescribeSpec examples in Kotest Spec Styles - Mocking — MockK setup, coroutine mocking, argument capture in MockK - TDD walkthrough — Full RED/GREEN/REFACTOR cycle with EmailValidator in TDD Workflow for Kotlin - Coverage...