claude-force: Skill for Claude Code

Test Generation Skill

Overview

Comprehensive patterns and best practices for generating high-quality automated tests across different testing frameworks and paradigms.

Capabilities

• Unit test generation (Jest, Vitest, pytest, JUnit)
• Integration test patterns
• E2E test creation (Playwright, Cypress)
• Test data generation
• Mock and stub creation
• Test coverage strategies

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Testing Frameworks

JavaScript/TypeScript

Jest/Vitest Patterns

Basic Unit Test Structure:

import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { functionToTest } from './module';

describe('ModuleName', () => {
  describe('functionToTest', () => {
    it('should return expected result for valid input', () => {
      // Arrange
      const input = 'test';
      const expected = 'TEST';

      // Act
      const result = functionToTest(input);

      // Assert
      expect(result).toBe(expected);
    });

    it('should throw error for invalid input', () => {
      expect(() => functionToTest(null)).toThrow('Invalid input');
    });
  });
});

Testing Async Functions:

it('should fetch user data successfully', async () => {
  const userId = '123';
  const userData = await fetchUser(userId);

  expect(userData).toHaveProperty('id', userId);
  expect(userData).toHaveProperty('name');
});

Testing React Components:

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

describe('Button', () => {
  it('should call onClick handler when clicked', () => {
    const handleClick = vi.fn();
    render(<Button onClick={handleClick}>Click me</Button>);

    const button = screen.getByRole('button', { name: /click me/i });
    fireEvent.click(button);

    expect(handleClick).toHaveBeenCalledTimes(1);
  });

  it('should be disabled when disabled prop is true', () => {
    render(<Button disabled>Click me</Button>);

    const button = screen.getByRole('button');
    expect(button).toBeDisabled();
  });
});