testing-strategies

# Testing Strategies

Build comprehensive, effective test suites by strategically selecting and implementing the right testing approaches across unit, integration, E2E, and contract testing levels.

## Purpose

This skill provides strategic frameworks for:
- **Test Type Selection**: Determine when to use unit vs. integration vs. E2E vs. contract testing
- **Test Pyramid Balancing**: Optimize test distribution for fast feedback and reliable coverage
- **Multi-Language Implementation**: Apply consistent testing patterns across TypeScript, Python, Go, and Rust
- **Test Data Management**: Choose appropriate strategies (fixtures, factories, property-based testing)
- **CI/CD Integration**: Integrate tests into automated pipelines with optimal execution patterns

Testing is foundational to reliable software. With microservices architectures and continuous delivery becoming standard in 2025, strategic testing across multiple levels is more critical than ever.

## When to Use This Skill

Invoke this skill when:
- Building a new feature that requires test coverage
- Designing a testing strategy for a new project
- Refactoring existing tests to improve speed or reliability
- Setting up CI/CD pipelines with testing stages
- Choosing between unit, integration, or E2E testing approaches
- Implementing contract testing for microservices
- Managing test data with fixtures, factories, or property-based testing

## The Testing Pyramid Framework

### Core Concept

The testing pyramid guides test distribution for optimal speed and confidence:

```
         /\
        /  \  E2E Tests (10%)
       /----\  - Slow but comprehensive
      /      \  - Full stack validation
     /--------\
    /          \  Integration Tests (20-30%)
   /            \  - Moderate speed
  /--------------\  - Component interactions
 /                \
/------------------\  Unit Tests (60-70%)
                      - Fast feedback
                      - Isolated units
```

**Key Principle**: More unit tests (fa