Kotlin Testing

# 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

1. **Identify target code** — Find the function, class, or module to test
2. **Write a Kotest spec** — Choose a spec style (StringSpec, FunSpec, BehaviorSpec) matching the test scope
3. **Mock dependencies** — Use MockK to isolate the unit under test
4. **Run tests (RED)** — Verify the test fails with the expected error
5. **Implement code (GREEN)** — Write minimal code to pass the test
6. **Refactor** — Improve the implementation while keeping tests green
7. **Check coverage** — Run `./gradlew koverHtmlReport` and verify 80%+ coverage

## Examples

The following sections contain detailed, runnable examples for each testing pattern:

### Quick Reference

- **Kotest specs** — StringSpec, FunSpec, BehaviorSpec, DescribeSpec examples in [Kotest Spec Styles](#kotest-spec-styles)
- **Mocking** — MockK setup, coroutine mocking, argument capture in [MockK](#mockk)
- **TDD walkthrough** — Full RED/GREEN/REFACTOR cycle with EmailValidator in [TDD Workflow for Kotlin](#tdd-workflow-for-kotlin)
- **Coverage** — Kover configuration and commands in [Kover Coverage](#kover-coverage)