kotlin-test

Kotlin TDD Command

This command enforces test-driven development methodology for Kotlin code using Kotest, MockK, and Kover.

What This Command Does

1. Define Types/Interfaces: Scaffold function signatures first
2. Write Kotest Tests: Create comprehensive test specs (RED)
3. Run Tests: Verify tests fail for the right reason
4. Implement Code: Write minimal code to pass (GREEN)
5. Refactor: Improve while keeping tests green
6. Check Coverage: Ensure 80%+ coverage with Kover

When to Use

Use /kotlin-test when:

• Implementing new Kotlin functions or classes
• Adding test coverage to existing Kotlin code
• Fixing bugs (write failing test first)
• Building critical business logic
• Learning TDD workflow in Kotlin

TDD Cycle

RED     -> Write failing Kotest test
GREEN   -> Implement minimal code to pass
REFACTOR -> Improve code, tests stay green
REPEAT  -> Next test case

Example Session

User: /kotlin-test I need a function to validate user registration requests

Agent:
# TDD Session: Registration Validator

## Step 1: Define Interface

```kotlin
// validator/RegistrationValidator.kt
package com.example.validator

data class RegistrationRequest(
    val name: String,
    val email: String,
    val password: String,
)

sealed class ValidationResult {
    data object Valid : ValidationResult()
    data class Invalid(val errors: List<String>) : ValidationResult()
}

fun validateRegistration(request: RegistrationRequest): ValidationResult {
    TODO("not implemented")
}
```

## Step 2: Write Kotest Tests (RED)

```kotlin
// validator/RegistrationValidatorTest.kt
package com.example.validator

import io.kotest.core.spec.style.FunSpec
import io.kotest.matchers.shouldBe
import io.kotest.matchers.types.shouldBeInstanceOf

class RegistrationValidatorTest : FunSpec({
    test("valid registration returns Valid") {
        val request = RegistrationRequest(
            name = "Alice",
            email = "[email protected]",
            password = "SecureP@ss1",
        )