Cypress Component Testing
Component testing requires Cypress v10 and above. See our guide for more information to migrate to Cypress v10.
Unlike E2E testing, component testing does not create a new project. Instead, Cypress component testing is added directly to a project, like Jest
Add Component Testing to a Project
Currently only @nx/react and @nx/angular plugins support component testing
Use the cypress-component-configuration generator from the respective plugin to add component testing to a project.
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nx g @nx/react:cypress-component-configuration --project=your-project nx g @nx/angular:cypress-component-configuration --project=your-project
You can optionally pass in --generate-tests to create component tests for all components within the library.
Component testing supports both applications and libraries. By default, the generator attempts to find the build target for you based on the project's dependent apps. But you can manually specify the build target to use via the --build-target option. Note, in most cases, the build target will be from a different project than the one being configured. The only case where the build targets are from the same project is when the component tests are being added to an application.
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nx g @nx/react:cypress-component-configuration --project=your-project --build-target=my-react-app:build nx g @nx/angular:cypress-component-configuration --project=your-project --build-target=my-ng-app:build
The build target option can be changed later via updating the devServerTarget option in the component-test target.
When using component testing make sure to set skipServe: true in the component test target options, otherwise @nx/cypress will attempt to run the build first which can slow down your component tests. skipServe: true is automatically set when using the cypress-component-configuration generator.
Configuration
When using the cypress-component-configuration generator, a helper function is used in the cypress.config.ts to setup the ideal settings for your project.
If you need to add additional configuration properties, you can spread the returned object from the helper function.
export default defineConfig({
component: {
...nxComponentTestingPreset(__filename),
// add your own config here
},
});
Testing Projects
Run nx component-test your-lib to execute the component tests with Cypress.
By default, Cypress will run in headless mode. You will have the result of all the tests and errors (if any) in your terminal. Screenshots and videos will be accessible in dist/cypress/libs/your-lib/screenshots and dist/cypress/libs/your-lib/videos.
Watching for Changes (Headed Mode)
With, nx component-test your-lib --watch Cypress will start in headed mode. Where you can see your component being tested.
Running Cypress with --watch is a great way to iterate on your components since cypress will rerun your tests as you make those changes validating the new behavior.
More Information
You can read more on component testing in the Cypress documentation.