javascript-testing-patterns
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.
Profile →npx skills add wshobson/agents --skill javascript-testing-patterns --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# JavaScript Testing Patterns Comprehensive guide for implementing robust testing strategies in JavaScript/TypeScript applications using modern testing frameworks and best practices. ## When to Use This Skill - 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 ## Testing Frameworks ### Jest - Full-Featured Testing Framework **Setup:** ```typescript // jest.config.ts import type { Config } from "jest"; const config: Config = { preset: "ts-jest", testEnvironment: "node", roots: ["<rootDir>/src"], testMatch: ["**/__tests__/**/*.ts", "**/?(*.)+(spec|test).ts"], collectCoverageFrom: [ "src/**/*.ts", "!src/**/*.d.ts", "!src/**/*.interface.ts", ], coverageThreshold: { global: { branches: 80, functions: 80, lines: 80, statements: 80, }, }, setupFilesAfterEnv: ["<rootDir>/src/test/setup.ts"], }; export default config; ``` ### Vitest - Fast, Vite-Native Testing **Set
- When to Use This Skill
- Testing Frameworks
- Jest - Full-Featured Testing Framework
- Vitest - Fast, Vite-Native Testing
- Unit Testing Patterns
- Pattern 1: Testing Pure Functions
- Pattern 2: Testing Classes
- Pattern 3: Testing Async Functions
- Mocking Patterns
- Pattern 1: Mocking Modules
- Pattern 2: Dependency Injection for Testing
- Pattern 3: Spying on Functions
- Integration Testing
- Frontend Testing with Testing Library
What does the javascript-testing-patterns skill do?
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.
How do I install it?
Run `npx skills add wshobson/agents --skill javascript-testing-patterns --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From wshobson/agents, a repository with 38,479 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.