Testing Strategies

When to use this skill

• New project: define a testing strategy
• Quality issues: bugs happen frequently
• Before refactoring: build a safety net
• CI/CD setup: automated tests

Instructions

Step 1: Understand the Test Pyramid

       /\
      /E2E\          ← few (slow, expensive)
     /______\
    /        \
   /Integration\    ← medium
  /____________\
 /              \
/   Unit Tests   \  ← many (fast, inexpensive)
/________________\

Ratio guide:

• Unit: 70%
• Integration: 20%
• E2E: 10%

Step 2: Unit testing strategy

Given-When-Then pattern:

describe('calculateDiscount', () => {
  it('should apply 10% discount for orders over $100', () => {
    // Given: setup
    const order = { total: 150, customerId: '123' };

    // When: perform action
    const discount = calculateDiscount(order);

    // Then: verify result
    expect(discount).toBe(15);
  });

  it('should not apply discount for orders under $100', () => {
    const order = { total: 50, customerId: '123' };
    const discount = calculateDiscount(order);
    expect(discount).toBe(0);
  });

  it('should throw error for invalid order', () => {
    const order = { total: -10, customerId: '123' };
    expect(() => calculateDiscount(order)).toThrow('Invalid order');
  });
});

Mocking strategy:

// Mock external dependencies
jest.mock('../services/emailService');
import { sendEmail } from '../services/emailService';

describe('UserService', () => {
  it('should send welcome email on registration', async () => {
    // Arrange
    const mockSendEmail = sendEmail as jest.MockedFunction<typeof sendEmail>;
    mockSendEmail.mockResolvedValueOnce(true);

    // Act
    await userService.register({ email: '[email protected]', password: 'pass' });

    // Assert
    expect(mockSendEmail).toHaveBeenCalledWith({
      to: '[email protected]',
      subject: 'Welcome!',
      body: expect.any(String)
    });
  });
});

Step 3: Integration Testing

API endpoint tests:

describe('POST /api/users', () => {
  beforeEach(async () => {
    await db.user.deleteMany();  // Clean DB
  });

  it('should create user with valid data', async () => {
    const response = await request(app)
      .post('/api/users')
      .send({
        email: '[email protected]',
        username: 'testuser',
        password: 'Password123!'
      });

    expect(response.status).toBe(201);
    expect(response.body.user).toMatchObject({
      email: '[email protected]',
      username: 'testuser'
    });

    // Verify it was actually saved to the DB
    const user = await db.user.findUnique({ where: { email: '[email protected]' } });
    expect(user).toBeTruthy();
  });

  it('should reject duplicate email', async () => {
    // Create first user
    await request(app)
      .post('/api/users')
      .send({ email: '[email protected]', username: 'user1', password: 'Pass123!' });

    // Attempt duplicate
    const response = await request(app)
      .post('/api/users')
      .send({ email: '[email protected]', username: 'user2', password: 'Pass123!' });

    expect(response.status).toBe(409);
  });
});

Step 4: E2E Testing (Playwright)

import { test, expect } from '@playwright/test';

test.describe('User Registration Flow', () => {
  test('should complete full registration process', async ({ page }) => {
    // 1. Visit homepage
    await page.goto('http://localhost:3000');

    // 2. Click Sign Up button
    await page.click('text=Sign Up')
how to use testing-strategies
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use testing-strategies on Cursor
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1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add testing-strategies
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/supercent-io/skills-template --skill testing-strategiescopy
The skills CLI fetches testing-strategies from GitHub repository supercent-io/skills-template and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
│   • Antigravity
│   • Cline
│   • Codex
│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/testing-strategies
Reload or restart Cursor to activate testing-strategies. Access the skill through slash commands (e.g., /testing-strategies) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?