Chromatic for Cypress

Chromatic’s visual tests integrate with Cypress via a plugin. This means you can transform your existing Cypress end-to-end (E2E) into visual regression tests with a single import change. Start capturing interactive snapshots while Cypress E2E tests run, and review visual changes in Chromatic’s cloud environment.

Why visual test with Cypress?

Cypress enables you to write E2E tests that drive the browser to simulate key user flows through your application, like ‘sign up’ and ‘add to cart’. By snapshotting the UI states generated during your E2E tests, you can proactively catch visual bugs that might slip through traditional logic-based tests.

How does Chromatic work?

Chromatic communicates with Cypress via the devtools protocol. While your Cypress E2E tests run, Chromatic captures an archive of the page and uploads it to the cloud. There, Chromatic generates snapshots and performs pixel diffing to identify any unintended visual changes.

Key advantages of Chromatic’s Cypress integration:

• Robustness: Chromatic saves full page archives (DOM, styling, assets) of every test case. This lets you interactively debug the UI within the Chromatic app, eliminating the need to run tests locally for troubleshooting.
• Workflow: Chromatic streamlines visual testing by removing the need to manually manage screenshots in your repo. Snapshots are indexed, linked to git commits, and stored in the cloud for easy access.
• Parallelized testing: Chromatic’s cloud infrastructure automatically scales to run all tests simultaneously, eliminating the need for you to configure multiple workers on your CI.
• Dedicated review app: Chromatic offers a suite of visual diffing tools to spot regressions fast. Features include unified and split diffs, highlighting ignored regions, spotlight mode to focus and zoom in on changes, and strobe diff to pinpoint subtle changes.

Setup Chromatic for Cypress

1. Sign up and create a new project

Generate a unique project token for your app by signing in to Chromatic and creating a project. Sign in with your GitHub, GitLab, Bitbucket, or email.

2. Install Chromatic

Install chromatic and @chromatic-com/cypress packages from npm.

$ npm install --save-dev chromatic @chromatic-com/cypress

$ yarn add --dev chromatic @chromatic-com/cypress

$ pnpm add --dev chromatic @chromatic-com/cypress

3. Add Chromatic to Cypress tests

Add the following to your cypress/support/e2e.js file:

// cypress/support/e2e.js
import "@chromatic-com/cypress/support";

Then, install the Chromatic plugin in your cypress.config.js file:

// cypress.config.js
const { defineConfig } = require("cypress");
const { installPlugin } = require("@chromatic-com/cypress");

module.exports = defineConfig({
  e2e: {
    setupNodeEvents(on, config) {
      installPlugin(on, config);
    },
  },
});

4. Run Cypress

Prefix your Cypress command with the following environment variable. This enables Chromatic to communicate with Cypress using the Chrome DevTools Protocol.

Then run your Cypress tests as you normally would.

$ ELECTRON_EXTRA_LAUNCH_ARGS=--remote-debugging-port=9222 npx cypress run

$ ELECTRON_EXTRA_LAUNCH_ARGS=--remote-debugging-port=9222 yarn cypress run

$ ELECTRON_EXTRA_LAUNCH_ARGS=--remote-debugging-port=9222 pnpm cypress run

5. Run Chromatic

Use your project token and run the following command in your project directory.

npx chromatic --cypress -t=<TOKEN>

When you execute the chromatic command, it uploads this archive to Chromatic’s cloud infrastructure to capture a snapshot of each test.

6. Review changes

When complete, you’ll see the build status and a link to review the changes. Click on that link to open Chromatic.

✔ Started build 1
  → Continue setup at https://www.chromatic.com/setup?appId=...
✔ Build 1 auto-accepted
  → Tested X stories across 10 components; captured 10 snapshots in 1 minute 3 seconds

The build will be marked “unreviewed” and the changes will be listed in the “Tests” table. Go through each snapshot to review the diff and approve or reject the change.

Once you accept all changes, your build is marked as passed 🟢. This updates the baselines for those tests, ensuring future snapshots are compared against the latest approved version.

Next: enhance your UI Testing workflow

You’re building robust components by uncovering bugs during development. Take your testing to the next level and safeguard against visual bugs by automating Chromatic whenever you push code.

Integrate Chromatic into your CI pipeline to get notified about any visual changes introduced by a pull request. Chromatic runs test any time you push code and reports changes via the “UI Tests” badge for your pull request.

Advanced configuration options

Take full control of your Chromatic and Cypress setup to match your team’s specific workflows. Here are some powerful customizations we offer:

• Take targeted snapshots: Learn how to programmatically capture snapshots at specific points during your tests.
• Fine-tune snapshot capture: Add delays before snapshots, modify the sensitivity threshold for change detection, and employ other granular controls.
• Test for flexible user preferences: Ensure your UI gracefully adapts to user preferences like forced-colors and prefers-reduced-motion.
• Responsive testing: Verify your UI’s responsiveness across various screen sizes. Easily configure viewport dimensions in Cypress, both globally and within individual tests.

Troubleshooting