Cypress Integration Testing

Trennt in Cypress klar zwischen echten API-Integrationstests und gemockten Tests.

Original-Beschreibung der Autoren: Cursor rules for Cypress development with integration testing.

Die Regel

---
description: "Cursor rules for Cypress development with integration testing."
globs: **/*
alwaysApply: false
---
# Persona

You are an expert QA engineer with deep knowledge of Cypress and TypeScript, tasked with creating integration tests for web applications.

# Auto-detect TypeScript Usage

Check for TypeScript in the project through tsconfig.json or package.json dependencies.
Adjust syntax based on this detection.

# Integration Testing Focus

Create tests that verify interactions between UI and API components
Focus on critical user flows and state transitions across multiple components
Mock API responses using cy.intercept to control test scenarios
Validate state updates and error handling across the integration points

# Best Practices

**1** **Critical Flows**: Prioritize testing end-to-end user journeys and key workflows
**2** **Data-testid Selectors**: Use data-testid attributes for reliable element selection
**3** **API Mocking**: Use cy.intercept to mock API responses and validate requests
**4** **State Validation**: Verify UI state updates correctly based on API responses
**5** **Error Handling**: Test both success paths and error scenarios
**6** **Test Organization**: Group related tests in descriptive describe blocks
**7** **No Visual Testing**: Avoid testing visual styles or pixel-perfect layouts
**8** **Limited Tests**: Create 3-5 focused tests per feature for maintainability

# Example Integration Test

```js
describe('Registration Form Integration', () => {
  beforeEach(() => {
    // Visit the registration page
    cy.visit('/register');
    
    // Mock the API response
    cy.intercept('POST', '/api/register', (req) => {
      if (req.body.email && req.body.email.includes('@')) {
        req.reply({ 
          statusCode: 200, 
          body: { message: 'Registration successful' }
        });
      } else {
        req.reply({ 
          statusCode: 400, 
          body: { error: 'Invalid email format' }
        });
      }
    }).as('registerRequest');
  });

  it('should submit form and display success message', () => {
    // Arrange: Fill out form with valid data
    cy.get('[data-testid="name-input"]').type('John Doe');
    cy.get('[data-testid="email-input"]').type('john@example.com');
    cy.get('[data-testid="password-input"]').type('Password123');
    
    // Act: Submit the form
    cy.get('[data-testid="register-button"]').click();
    
    // Wait for API request to complete
    cy.wait('@registerRequest').its('request.body').should('include', {
      name: 'John Doe',
      email: 'john@example.com'
    });
    
    // Assert: Verify success message is displayed
    cy.get('[data-testid="success-message"]')
      .should('be.visible')
      .and('contain', 'Registration successful');
      
    // Assert: Verify redirect to dashboard
    cy.url().should('include', '/dashboard');
  });

  it('should show error message for invalid email', () => {
    // Arrange: Fill out form with invalid email
    cy.get('[data-testid="name-input"]').type('John Doe');
    cy.get('[data-testid="email-input"]').type('invalid-email');
    cy.get('[data-testid="password-input"]').type('Password123');
    
    // Act: Submit the form
    cy.get('[data-testid="register-button"]').click();
    
    // Wait for API request to complete
    cy.wait('@registerRequest');
    
    // Assert: Verify error message is displayed
    cy.get('[data-testid="error-message"]')
      .should('be.visible')
      .and('contain', 'Invalid email format');
      
    // Assert: Verify we stay on the registration page
    cy.url().should('include', '/register');
  });

  it('should validate input fields before submission', () => {
    // Act: Submit the form without filling any fields
    cy.get('[data-testid="register-button"]').click();
    
    // Assert: Form validation errors should be displayed
    cy.get('[data-testid="name-error"]').should('be.visible');
    cy.get('[data-testid="email-error"]').should('be.visible');
    cy.get('[data-testid="password-error"]').should('be.visible');
    
    // Assert: No API request should be made
    cy.get('@registerRequest.all').should('have.length', 0);
  });
});

TypeScript Example

// Define types for the API responses
interface RegisterSuccessResponse {
  message: string;
}

interface RegisterErrorResponse {
  error: string;
}

describe('Shopping Cart Integration', () => {
  beforeEach(() => {
    // Visit the products page
    cy.visit('/products');
    
    // Mock the products API
    cy.intercept('GET', '/api/products', {
      statusCode: 200,
      body: [
        { id: 1, name: 'Product A', price: 19.99, inStock: true },
        { id: 2, name: 'Product B', price: 29.99, inStock: true },
        { id: 3, name: 'Product C', price: 39.99, inStock: false }
      ]
    }).as('getProducts');
    
    // Mock the cart API
    cy.intercept('POST', '/api/cart/add', (req) => {
      const productId = req.body.productId;
      if (productId === 3) {
        req.reply({
          statusCode: 400,
          body: { error: 'Product out of stock' }
        });
      } else {
        req.reply({
          statusCode: 200,
          body: { 
            message: 'Product added to cart',
            cartCount: 1
          }
        });
      }
    }).as('addToCart');
  });

  it('should add in-stock product to cart', () => {
    // Wait for products to load
    cy.wait('@getProducts');
    
    // Verify products are displayed
    cy.get('[data-testid="product-item"]').should('have.length', 3);
    
    // Add first product to cart
    cy.get('[data-testid="product-item"]').first()
      .find('[data-testid="add-to-cart"]')
      .click();
    
    // Wait for API request to complete
    cy.wait('@addToCart').its('request.body').should('deep.equal', {
      productId: 1,
      quantity: 1
    });
    
    // Verify cart count is updated
    cy.get('[data-testid="cart-count"]').should('contain', '1');
    
    // Verify success message
    cy.get
… (hier gekürzt — Kopieren/Download liefert die vollständige Regel)

So nutzt du sie

Die Regel kopieren (Button oben) oder als Datei herunterladen und im Projekt unter .cursor/rules/ ablegen — Cursor lädt sie beim nächsten Start automatisch. Ältere Cursor-Versionen lesen alternativ eine einzelne .cursorrules-Datei im Projektstamm; dort einfach den Regel-Text ohne den Kopfblock zwischen den ----Zeilen einfügen.

Der Regel-Text ist englisch — Cursor versteht ihn unabhängig von der Sprache, in der Sie mit dem Editor chatten.

Im Detail

Diese Regel trennt sauber zwischen echten Integrationstests, die reale API-Aufrufe nutzen, und Tests mit gemockten Antworten. Sie gibt vor, wann welches Vorgehen angemessen ist, und verhindert, dass Mocks versehentlich echtes Backend-Verhalten verdecken oder Integrationstests durch instabile externe Dienste unzuverlässig werden. Nützlich für Projekte, die sowohl schnelle, isolierte Tests als auch belastbare End-to-End-Absicherung brauchen und bisher keine klare Linie dafür hatten. Wer nur Unit-Tests oder nur volle E2E-Tests fährt, profitiert weniger, da die Regel genau auf die Grauzone dazwischen zielt.

Praxis-Tipp

Bei der Testplanung fragen “soll das ein echter API-Call oder ein Mock sein?” und die Regel entscheiden lassen, welches Muster passt.

Lizenz & Quelle

• Lizenz: CC0 1.0
• Quelle: PatrickJS/awesome-cursorrules (GitHub)

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