b4san/testing-qa

Testing & QA

Automated test generation, maintenance, and quality assurance for comprehensive code validation.

When to Use This Skill

Use this skill when:

• Writing tests for new features or components
• Maintaining existing tests after API or UI changes
• Generating synthetic test data for development/testing
• Debugging failing tests or investigating coverage gaps
• Setting up test infrastructure for a project
• Running test suites and analyzing results

Instructions

Step 1: Analyze Test Requirements

1. Review the specification or change document
2. Identify testable components:
   • Business logic functions
   • API endpoints
   • UI components/interactions
   • Integration points
3. Determine test types needed:
   • Unit tests (isolated functions)
   • Integration tests (component interactions)
   • E2E tests (user workflows)

Step 2: Generate Test Cases

For each component, generate tests covering:

Unit Tests:

• Happy path (normal operation)
• Edge cases (empty input, max values, nulls)
• Error cases (exceptions, invalid inputs)
• Boundary conditions

Integration Tests:

• Component interactions
• Data flow between modules
• API contract validation
• Database operations

E2E Tests:

• Critical user workflows
• Multi-step processes
• Cross-browser compatibility (if applicable)
• Mobile responsiveness (if applicable)

Step 3: Create Test Files

Follow project conventions:

test-file-naming:
  unit: "*.test.js" or "*.spec.js"
  integration: "*.integration.test.js"
  e2e: "*.e2e.test.js" or in "e2e/" folder

test-structure:
  describe: "Component/Feature name"
  it: "should [expected behavior] when [condition]"

Step 4: Generate Test Data

Create realistic test data:

Static Data:

const mockUsers = [
  { id: 1, name: "John Doe", email: "[email protected]" },
  { id: 2, name: "Jane Smith", email: "[email protected]" }
];

Dynamic Data (using factories):

const generateUser = (overrides = {}) => ({
  id: faker.datatype.uuid(),
  name: faker.name.fullName(),
  email: faker.internet.email(),
  ...overrides
});

Synthetic Data for Load Testing:

• Large datasets for performance testing
• Edge case data (max length strings, special characters)
• Internationalization test data (Unicode, RTL languages)

Step 5: Implement Tests

Write tests following best practices:

Arrange-Act-Assert Pattern:

test('should calculate total price with tax', () => {
  // Arrange
  const cart = { items: [{ price: 100, quantity: 2 }] };
  const taxRate = 0.08;
  
  // Act
  const total = calculateTotal(cart, taxRate);
  
  // Assert
  expect(total).toBe(216); // 200 + 16 tax
});

Mock External Dependencies:

jest.mock('../api/client', () => ({
  fetchUser: jest.fn()
}));

beforeEach(() => {
  fetchUser.mockResolvedValue({ id: 1, name: 'Test User' });
});

Step 6: Run Tests and Debug

1. Execute test suite:

   npm test
   # or
   npm run test:unit
   npm run test:integration
   npm run test:e2e
   

2. Analyze failures:

   • Read error messages carefully
   • Check stack traces
   • Verify mocks are set up correctly
   • Compare expected vs actual values

3. Debug failing tests:

   • Add console.log for debugging
   • Use debugger statement
   • Check test isolation (beforeEach/afterEach)
   • Verify async handling (await, done callback)

Step 7: Maintain Tests

When APIs or UI changes:

1. Identify affected tests (run test suite)
2. Update test expectations to match new behavior
3. Add new tests for new functionality
4. Remove obsolete tests for removed features
5. Update mocks to match new interfaces

Step 8: Coverage Analysis

1. Run coverage report:

   npm run test:coverage
   

2. Identify gaps:

   • Uncovered branches (if/else conditions)
   • Missing edge cases
   • Untested error paths

3. Add tests to cover gaps

Integration with OpenSpec

• Use openspec-verify-change to validate tests pass
• Link test files to tasks in tasks.md
• Include test requirements in design.md
• Reference test coverage in verification reports

Guardrails

• Test behavior, not implementation - Tests should verify what code does, not how
• One assertion per test (ideally) - Makes failures clearer
• Keep tests fast - Unit tests should run in milliseconds
• Mock external systems - Don't hit real databases/APIs in unit tests
• Clean up after tests - Use afterEach to reset state
• Don't test framework code - Focus on business logic

Common Patterns

Testing Async Code:

test('should fetch user data', async () => {
  const user = await fetchUser(1);
  expect(user).toEqual({ id: 1, name: 'John' });
});

Testing React Components:

import { render, screen, fireEvent } from '@testing-library/react';

test('should toggle visibility on click', () => {
  render(<ToggleButton />);
  const button = screen.getByRole('button');
  
  fireEvent.click(button);
  expect(screen.getByText('Visible')).toBeInTheDocument();
  
  fireEvent.click(button);
  expect(screen.queryByText('Visible')).not.toBeInTheDocument();
});

Testing API Endpoints:

import request from 'supertest';
import app from '../app';

test('POST /api/users should create user', async () => {
  const response = await request(app)
    .post('/api/users')
    .send({ name: 'John', email: '[email protected]' });
    
  expect(response.status).toBe(201);
  expect(response.body).toHaveProperty('id');
});

Requirements

• Access to test runner (Jest, Mocha, Vitest, etc.)
• Test utilities (@testing-library/react, supertest, etc.)
• Code coverage tool (Istanbul, c8, etc.)
• Access to the codebase being tested

See Also

• test-generator - Generate initial test suite
• openspec-verify-change - Validate implementation with tests
• systematic-debugging - Debug failing tests
• secure-coding-cybersecurity - Security-focused testing