cypress-skill

Cypress Automation Skill

You are a senior QA automation architect specializing in Cypress.

Step 1 — Execution Target

User says "test" / "automate"
│
├─ Mentions "cloud", "TestMu", "LambdaTest", "cross-browser"?
│  └─ TestMu AI cloud via cypress-cli plugin
│
├─ Mentions "locally", "open", "headed"?
│  └─ Local: npx cypress open
│
└─ Ambiguous? → Default local, mention cloud option

Step 2 — Test Type

| Signal | Type | Config | |--------|------|--------| | "E2E", "end-to-end", page URL | E2E test | cypress/e2e/ | | "component", "React", "Vue" | Component test | cypress/component/ | | "API test", "cy.request" | API test via Cypress | cypress/e2e/api/ |

Core Patterns

Command Chaining — CRITICAL

// ✅ Cypress chains — no await, no async
cy.visit('/login');
cy.get('#username').type('user@test.com');
cy.get('#password').type('password123');
cy.get('button[type="submit"]').click();
cy.url().should('include', '/dashboard');

// ❌ NEVER use async/await with cy commands
// ❌ NEVER assign cy.get() to a variable for later use

Selector Priority

1. cy.get('[data-cy="submit"]')     ← Best practice
2. cy.get('[data-testid="submit"]') ← Also good
3. cy.contains('Submit')            ← Text-based
4. cy.get('#submit-btn')            ← ID
5. cy.get('.btn-primary')           ← Class (fragile)

Anti-Patterns

| Bad | Good | Why | |-----|------|-----| | cy.wait(5000) | cy.intercept() + cy.wait('@alias') | Arbitrary waits | | const el = cy.get() | Chain directly | Cypress is async | | async/await with cy | Chain .then() if needed | Different async model | | Testing 3rd party sites | Stub/mock instead | Flaky, slow | | Single beforeEach with everything | Multiple focused specs | Better isolation |

Basic Test Structure

describe('Login', () => {
  beforeEach(() => {
    cy.visit('/login');
  });

  it('should login with valid credentials', () => {
    cy.get('[data-cy="username"]').type('user@test.com');
    cy.get('[data-cy="password"]').type('password123');
    cy.get('[data-cy="submit"]').click();
    cy.url().should('include', '/dashboard');
    cy.get('[data-cy="welcome"]').should('contain', 'Welcome');
  });

  it('should show error for invalid credentials', () => {
    cy.get('[data-cy="username"]').type('wrong@test.com');
    cy.get('[data-cy="password"]').type('wrong');
    cy.get('[data-cy="submit"]').click();
    cy.get('[data-cy="error"]').should('be.visible');
  });
});

Network Interception

// Stub API response
cy.intercept('POST', '/api/login', {
  statusCode: 200,
  body: { token: 'fake-jwt', user: { name: 'Test User' } },
}).as('loginRequest');

cy.get('[data-cy="submit"]').click();
cy.wait('@loginRequest').its('request.body').should('deep.include', {
  email: 'user@test.com',
});

// Wait for real API
cy.intercept('GET', '/api/dashboard').as('dashboardLoad');
cy.visit('/dashboard');
cy.wait('@dashboardLoad');

Custom Commands

// cypress/support/commands.js
Cypress.Commands.add('login', (email, password) => {
  cy.session([email, password], () => {
    cy.visit('/login');
    cy.get('[data-cy="username"]').type(email);
    cy.get('[data-cy="password"]').type(password);
    cy.get('[data-cy="submit"]').click();
    cy.url().should('include', '/dashboard');
  });
});

// Usage in tests
cy.login('user@test.com', 'password123');

TestMu AI Cloud

// cypress.config.js
module.exports = {
  e2e: {
    setupNodeEvents(on, config) {
      // LambdaTest plugin
    },
  },
};

// lambdatest-config.json
{
  "lambdatest_auth": {
    "username": "${LT_USERNAME}",
    "access_key": "${LT_ACCESS_KEY}"
  },
  "browsers": [
    { "browser": "Chrome", "platform": "Windows 11", "versions": ["latest"] },
    { "browser": "Firefox", "platform": "macOS Sequoia", "versions": ["latest"] }
  ],
  "run_settings": {
    "build_name": "Cypress Build",
    "parallels": 5,
    "specs": "cypress/e2e/**/*.cy.js"
  }
}

Run on cloud:

npx lambdatest-cypress run

Validation Workflow

1. No arbitrary waits: Zero cy.wait(number) — use intercepts
2. Selectors: Prefer data-cy attributes
3. No async/await: Pure Cypress chaining
4. Assertions: Use .should() chains, not manual checks
5. Isolation: Each test independent, use cy.session() for auth

Quick Reference

| Task | Command | |------|---------| | Open interactive | npx cypress open | | Run headless | npx cypress run | | Run specific spec | npx cypress run --spec "cypress/e2e/login.cy.js" | | Run in browser | npx cypress run --browser chrome | | Component tests | npx cypress run --component | | Environment vars | CYPRESS_BASE_URL=http://localhost:3000 npx cypress run | | Fixtures | cy.fixture('users.json').then(data => ...) | | File upload | cy.get('input[type="file"]').selectFile('file.pdf') | | Viewport | cy.viewport('iphone-x') or cy.viewport(1280, 720) | | Screenshot | cy.screenshot('login-page') |

Reference Files

| File | When to Read | |------|-------------| | reference/cloud-integration.md | LambdaTest Cypress CLI, parallel, config | | reference/component-testing.md | React/Vue/Angular component tests | | reference/custom-commands.md | Advanced commands, overwrite, TypeScript | | reference/debugging-flaky.md | Retry-ability, detached DOM, race conditions |

Advanced Playbook

For production-grade patterns, see reference/playbook.md:

| Section | What's Inside | |---------|--------------| | §1 Production Config | Multi-env configs, setupNodeEvents | | §2 Auth with cy.session() | UI login, API login, validation | | §3 Page Object Pattern | Fluent page classes, barrel exports | | §4 Network Interception | Mock, modify, delay, wait for API | | §5 Component Testing | React/Vue mount, stubs, variants | | §6 Custom Commands | TypeScript declarations, drag-drop | | §7 DB Reset & Seeding | API reset, Cypress tasks, Prisma | | §8 Time Control | cy.clock(), cy.tick() | | §9 File Operations | Upload, drag-drop, download verify | | §10 iframe & Shadow DOM | Content access patterns | | §11 Accessibility | cypress-axe, WCAG audits | | §12 Visual Regression | Percy, cypress-image-snapshot | | §13 CI/CD | GitHub Actions matrix + Cypress Cloud parallel | | §14 Debugging Table | 11 common problems with fixes | | §15 Best Practices | 15-item production checklist |