jest-generator

# Jest Generator Skill ## Purpose Generate Jest-based unit tests for JavaScript and TypeScript code, following Jest conventions and best practices with proper mocking, describe blocks, and code organization. ## When to Use - Generate Jest tests for JavaScript/TypeScript modules - Create test files for React components - Add missing test coverage to existing code - Need Jest-specific patterns (mocks, spies, snapshots) ## Test File Naming **Source to Test Mapping:** - `src/components/Feature.tsx` → `src/components/Feature.test.tsx` - `src/utils/validator.ts` → `src/utils/validator.test.ts` - `src/models/User.ts` → `src/models/User.test.ts` ## Running Tests ```bash # Preferred: Using bun (faster) bun test # Run specific file bun test src/utils/validator.test.ts # Run with coverage bun test --coverage # Watch mode bun test --watch # Alternative: Using npm npm test npm test -- --coverage ``` ## Jest Test Structure ```typescript import { functionToTest, ClassToTest } from './Feature' jest.mock('./dependency') describe('ModuleName', () => { beforeEach(() => { jest.clearAllMocks() }) afterEach(() => { jest.restoreAllMocks() }) describe('ClassName', () => { let instance: ClassToTest beforeEach(() => { instance = new ClassToTest() }) it('should return expected result with valid input', () => { // Arrange const input = { key: 'value' } const expected = { processed: true } // Act const result = ins...