Configuring Cypress for Effective Web Testing

Understanding Cypress Configuration Files

Where to Find Configuration Files

Starting with Cypress 10, you’ll store your settings in cypress.config.js or cypress.config.ts in your project’s main folder. Here’s what it looks like:

<code>const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    baseUrl: 'https://example.com',
    specPattern: 'cypress/e2e/**/*.cy.{js,jsx,ts,tsx}',
    setupNodeEvents(on, config) {
      <em>// add event listeners here</em>
    },
  },
})

Moving from Older Versions

Were you using Cypress 9 or earlier? If so, your settings were probably in cypress.json. Fortunately, upgrading is easy. First, run this command:

<code>npx cypress open

After that, Cypress will find your old settings and offer to move them to the new format automatically.

Essential Cypress Configuration Options

Setting Your Test Website Address

The most important setting is probably the baseUrl. This tells Cypress which website to test:

<code>module.exports = defineConfig({
  e2e: {
    baseUrl: 'https://example.com',
  },
})

Once you set this up, you can use shorter paths in your tests:

<code><em>// Instead of cy.visit('https://example.com/login')</em>
cy.visit('/login')

As a result, your tests become easier to maintain and you can switch between testing environments quickly.

Setting Screen Size for Tests

Cypress lets you choose default screen dimensions for your tests:

<code>module.exports = defineConfig({
  e2e: {
    viewportWidth: 1280,
    viewportHeight: 720,
  },
})

Moreover, you can change screen size within specific tests:

<code><em>// Test for mobile viewport</em>
it('displays mobile menu on small screens', () => {
  cy.viewport(375, 667)
  cy.visit('/')
  cy.get('.mobile-menu-button').should('be.visible')
})

Adjusting Wait Times

Cypress commands wait for elements by default, but sometimes you need more time. Therefore, you can adjust these waiting periods:

<code>module.exports = defineConfig({
  defaultCommandTimeout: 5000,  <em>// milliseconds</em>
  pageLoadTimeout: 30000,
  requestTimeout: 10000,
})

For slower websites or networks, higher values help prevent false failures.

Setting Up Different Testing Environments

Creating Multiple Environment Settings

Most projects need testing in different places (development, staging, production). Cypress makes this simple:

<code>module.exports = defineConfig({
  e2e: {
    env: {
      development: {
        baseUrl: 'http://localhost:3000',
      },
      staging: {
        baseUrl: 'https://staging.example.com',
      },
      production: {
        baseUrl: 'https://example.com',
      }
    }
  },
})

Afterwards, use these environments in your tests:

<code>const environment = Cypress.env('environment') || 'development'
const config = Cypress.env(environment)
cy.visit(config.baseUrl)

Using Environment Variables in Cypress

Cypress can access environment variables from your system:

<code><em>// Set variable when running Cypress</em>
<em>// CYPRESS_API_URL=https://api.example.com npx cypress run</em>

<em>// Access in tests</em>
cy.request(Cypress.env('API_URL') + '/users')

This keeps sensitive information out of your code repository.

Advanced Cypress Configuration Techniques

Adding Custom Plugins

Plugins add extra features to Cypress. Set them up in your configuration:

<code>module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      on('task', {
        log(message) {
          console.log(message)
          return null
        },
      })
      
      return config
    },
  },
})

Managing Screenshots and Videos

By default, Cypress takes screenshots when tests fail and records videos during headless runs. You can control these features:

<code>module.exports = defineConfig({
  screenshotOnRunFailure: true,
  video: true,
  videoCompression: 32,
  videosFolder: 'cypress/videos',
  screenshotsFolder: 'cypress/screenshots',
})

In addition, you might want to turn off videos in some cases:

<code>module.exports = defineConfig({
  video: process.env.CI ? false : true,
})

Setting Test File Patterns

You can control which files Cypress sees as tests:

<code>module.exports = defineConfig({
  e2e: {
    specPattern: 'cypress/e2e/**/*.{cy,spec}.{js,jsx,ts,tsx}',
    excludeSpecPattern: ['**/ignored-tests/**', '**/node_modules/**'],
  },
})

Best Practices for Cypress Configuration

Sharing Configuration Between Team Members

Keep settings consistent across your team by:

1. First, add cypress.config.js to version control
2. Next, use environment variables for changing values
3. Finally, document any special local settings

Settings for Better Performance

Speed up your tests with these options:

<code>module.exports = defineConfig({
  numTestsKeptInMemory: 50,  <em>// Default is 50</em>
  experimentalMemoryManagement: true,
  retries: {
    runMode: 2,  <em>// Retry failed tests in CI</em>
    openMode: 0,  <em>// Don't retry in dev mode</em>
  },
})

Settings for Different Testing Types

Different testing needs require different settings:

<code>module.exports = defineConfig({
  e2e: {
    <em>// For component testing</em>
    includeShadowDom: true,
    
    <em>// For API testing</em>
    experimentalSessionAndOrigin: true,
    
    <em>// For accessibility testing</em>
    experimentalStudio: true,
  },
})

Fixing Configuration Problems

Common Setup Issues

Watch for these frequent problems:

1. First, check file paths match your project structure
2. Second, use TypeScript to catch errors early
3. Lastly, make sure plugins are installed correctly

Finding Configuration Bugs

When you have setup problems:

1. First, look at Cypress logs in the console
2. Then, print settings with console.log(Cypress.config())
3. Alternatively, run with DEBUG=cypress:* npx cypress open for detailed output

Next Steps After Configuration

After setting up:

1. Share your config with your team
2. Document any special settings
3. Consider adding scripts to switch environments easily

Conclusion

Good Cypress setup creates the foundation for solid, reliable tests. By understanding your options and following best practices, you can build a testing system that works well for everyone on your team.

In our next article, we’ll use these settings to create your first real Cypress test using Google.com as an example.

Another Steps to use Cypress:

Check out the other posts in our Cypress series on the blog:

• Introduction to Cypress: Modern JavaScript Testing Framework
• Getting Started with Cypress: Installation and Setup Guide
• Configuring Your Cypress Environment for Optimal Testing
• Creating Your First Cypress Test: Step-by-Step Google Search Example
• Mastering Cypress Test Execution and Debugging Techniques
• Cypress Best Practices: Building Reliable and Maintainable Tests