JavaScript Testing Patterns

---
version: 4.1.0-fractal
name: javascript-testing-patterns-36c7e8faab36
description: Implement comprehensive testing strategies using Jest, Vitest, and Testing Library for unit tests, integration tests, and end-to-end testing with mocking, fixtures, and test-driven development. Use when writing JavaScript/TypeScript tests, setting up test infrastructure, or implementing TDD/BDD workflows.
---

# JavaScript Testing Patterns

Comprehensive guide for implementing robust testing strategies in JavaScript/TypeScript applications using modern testing frameworks and best practices.

## Use this skill when

- Setting up test infrastructure for new projects
- Writing unit tests for functions and classes
- Creating integration tests for APIs and services
- Implementing end-to-end tests for user flows
- Mocking external dependencies and APIs
- Testing React, Vue, or other frontend components
- Implementing test-driven development (TDD)
- Setting up continuous testing in CI/CD pipelines

## Do not use this skill when

- The task is unrelated to javascript testing patterns
- You need a different domain or tool outside this scope

## Instructions

- Clarify goals, constraints, and required inputs.
- Apply relevant best practices and validate outcomes.
- Provide actionable steps and verification.
- If detailed examples are required, open `resources/implementation-playbook.md`.

## Resources

- `resources/implementation-playbook.md` for detailed patterns and examples.


## 🧠 Knowledge Modules (Fractal Skills)

### 1. [implementation-playbook](./sub-skills/implementation-playbook.md)