test-generator

# Test Generator Skill Auto-suggest tests when you write new code. ## When I Activate - ✅ New function created - ✅ New component added - ✅ User mentions testing or tests - ✅ Test file missing for implementation - ✅ User asks "can you test this?" ## What I Generate ### Quick Test Scaffolding - Basic happy path tests - Null/undefined edge cases - Simple error scenarios - Framework-appropriate syntax (Jest/Vitest/Pytest) ### What I Don't Do - Comprehensive test suites → Use **@test-engineer** sub-agent - Integration tests → Use **@test-engineer** sub-agent - E2E test design → Use **@test-engineer** sub-agent - Test strategy planning → Use **@test-engineer** sub-agent ## Relationship with @test-engineer Sub-Agent **Me (Skill):** Quick test scaffolding **@test-engineer (Sub-Agent):** Comprehensive testing strategy ### Workflow 1. You write a function 2. I auto-generate basic test structure 3. You want full suite → Invoke **@test-engineer** sub-agent 4. Sub-agent creates comprehensive tests ## Examples ### JavaScript Function ```javascript // You write: function calculateDiscount(price, percentage) { if (price <= 0) throw new Error('Invalid price'); return price * (percentage / 100); } // I auto-generate: describe('calculateDiscount', () => { it('calculates discount correctly', () => { expect(calculateDiscount(100, 10)).toBe(10); }); it('throws error for invalid price', () => { expect(() => calculateDiscount(0, 10)).toThrow('Invalid price'); }); it('handles zero percentage', () => { expect(calculateDiscount(100, 0)).toBe(0); }); // TODO: Add more edge cases // Consider: negative percentages, decimal values, very large numbers }); ``` ### React Component ```jsx // You write: function UserCard({ user, onEdit }) { return ( <div className="user-card"> <h2>{user.name}</h2> <button onClick={() => onEdit(user.id)}>Edit</button> </div> ); } // I auto-generate: import { render, screen, fireEvent } from '@testing-library/react'; describe('UserCard', () => { const mockUser = { id: 1, name: 'John Doe' }; const mockOnEdit = jest.fn(); it('renders user name', () => { render(<UserCard user={mockUser} onEdit={mockOnEdit} />); expect(screen.getByText('John Doe')).toBeInTheDocument(); }); it('calls onEdit with user id when button clicked', () => { render(<UserCard user={mockUser} onEdit={mockOnEdit} />); fireEvent.click(screen.getByText('Edit')); expect(mockOnEdit).toHaveBeenCalledWith(1); }); // TODO: Add tests for edge cases // - Missing user data // - Undefined onEdit // - Long names (UI testing) }); ``` ### Python Function ```python # You write: def fetch_user_data(user_id: int) -> dict: if user_id <= 0: raise ValueError("Invalid user ID") return db.query("SELECT * FROM users WHERE id = ?", [user_id]) # I auto-generate: import pytest def test_fetch_user_data_success(): """Test successful user data retrieval""" result = fetch_user_data(1) assert isinstance(result, dict) assert 'id' in result def test_fetch_user_data_invalid_id(): """Test with invalid user ID""" with pytest.raises(ValueError, match="Invalid user ID"): fetch_user_data(0) def test_fetch_user_data_negative_id(): """Test with negative ID""" with pytest.raises(ValueError): fetch_user_data(-1) # TODO: Add integration tests with database # TODO: Test database connection failures ``` ## Framework Detection I automatically detect your testing framework: - **JavaScript/TypeScript**: Jest, Vitest, Mocha - **Python**: pytest, unittest - **Java**: JUnit - **Go**: testing package Detection based on: - package.json dependencies - requirements.txt - Existing test files - Import statements ## Test Patterns ### Unit Tests ```javascript // Function testing test('adds numbers correctly', () => { expect(add(2, 3)).toBe(5); }); ``` ### Component Tests ```jsx // React component testing test('button click triggers callback', () => { const onClick = jest.fn(); render(<Button onClick={onClick} />); fireEvent.click(screen.getByRole('button')); expect(onClick).toHaveBeenCalled(); }); ``` ### Edge Cases ```javascript // Boundary testing test('handles empty input', () => { expect(processData([])).toEqual([]); }); test('handles null input', () => { expect(processData(null)).toBeNull(); }); ``` ## When to Use Sub-Agent Invoke **@test-engineer** for: - Complete test suites (20+ tests) - Integration test strategy - E2E test planning - Test coverage goals - Complex mocking scenarios **Example:** ``` Me: "Generated 3 basic tests for calculateDiscount()" You: "@test-engineer create comprehensive test suite with all edge cases" Sub-agent: [Creates 25+ tests covering all scenarios] ``` ## Sandboxing Compatibility **Works without sandboxing:** ✅ Yes **Works with sandboxing:** ✅ Yes - **Filesystem**: Writes test files to project - **Network**: None required - **Configuration**: None required ## Customization Edit test templates: ```bash cp -r ~/.claude/skills/development/test-generator \ ~/.claude/skills/development/my-test-generator # Edit SKILL.md to customize: # - Test patterns # - Framework preferences # - Coverage expectations ``` ## Integration with Commands ### /test-gen Command ```bash /test-gen --file utils.js --framework jest --coverage 90 # Combines: # 1. My quick scaffolding # 2. @test-engineer comprehensive tests # 3. Full test file generation ``` ## Tips 1. **Let me scaffold first** - Review before invoking sub-agent 2. **Add TODOs** - I include TODO comments for complex cases 3. **Framework consistency** - I match your project's testing style 4. **Quick iteration** - Regenerate if not satisfied ## Related Tools - **@test-engineer**: Comprehensive test suite creation - **code-reviewer skill**: Flags code that needs testing - **/test-gen command**: Full test generation workflow