Kotlin Testing

Covers the full TDD cycle in Kotlin with Kotest specs, MockK mocking, coroutine testing, and Kover coverage reporting. You get working examples of StringSpec, FunSpec, BehaviorSpec, and DescribeSpec styles, plus a proper RED-GREEN-REFACTOR walkthrough with an email validator. The matchers section is solid for assertions, and the MockK examples show coEvery for suspending functions and verification patterns. Includes Ktor testApplication setup if you're testing HTTP routes. The 80% coverage target with Kover is reasonable, and the examples are copy-paste ready. Good reference if you want idiomatic Kotlin tests instead of fighting with JUnit patterns that don't fit the language.

skills.sh installs: 5.7K
GitHub stars: 300.3K
last updated: Aug 21, 2026

View on GitHub

Install

$ npx -y skills add affaan-m/ecc --skill kotlin-testing --agent claude-code

Installs into .claude/skills of the current project.

Files

Kotlin Testing Patterns

Comprehensive Kotlin testing patterns for writing reliable, maintainable tests following TDD methodology with Kotest and MockK.

When to Use

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

How It Works

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