stack-kotlin-testing

name	stack-kotlin-testing
description	Kotlin testing standards — Kotest, Mockk, JUnit 5
license	Apache-2.0
metadata	{"author":"manuel-retamozo-garcia","version":"1.0"}
capabilities	["kotlin"]

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 or data-driven tests
• Following TDD workflow in Kotlin projects
• Configuring Kover for code coverage
• Testing Ktor HTTP routes

Core Rules

1. RED-GREEN-REFACTOR Cycle: Always write a failing test first, then minimal implementation to pass, then refactor.
2. Kotest Spec Styles: Use standard spec styles (StringSpec for simple, FunSpec for JUnit-like, BehaviorSpec for BDD) consistently across files.
3. MockK Mocking: Mock interfaces and abstract classes, never data classes. Use coEvery / coVerify for suspend functions. Clear mocks in beforeTest.
4. Coroutine testing: Wrap tests in runTest. For testing time-based flows, use StandardTestDispatcher and advance virtual time with advanceTimeBy or advanceUntilIdle.
5. Kover Code Coverage: Aim for at least 80% coverage on general code and 100% on critical business logic. Exclude generated code and configuration classes from reports.

References

For full code examples, step-by-step TDD walkthroughs, custom matchers, arg captors, flow testing, property-based setups, and Ktor route testing, refer to:

• Kotlin Testing Patterns & Examples