Cypress is a test runner built for the modern web. It has a lot of great features:
- Time travel
- Real-time reloads
- Automatic waiting
- Spies, stubs, and clocks
- Network traffic control
- Screenshots and videos
Setting Up Cypress
Info about Cypress Component Testing can be found here
If the @nrwl/cypress package is not installed, install the version that matches your nx package version.
yarn add --dev @nrwl/cypress
npm install --save-dev @nrwl/cypress
E2E Testing
By default, when creating a new frontend application, Nx will use Cypress to create the e2e tests project.
nx g @nrwl/web:app frontend
Creating a Cypress E2E project for an existing project
To generate an E2E project based on an existing project, run the following generator
nx g @nrwl/cypress:cypress-project your-app-name-e2e --project=your-app-name
Optionally, you can use the --baseUrl option if you don't want cypress plugin to serve your-app-name.
nx g @nrwl/cypress:cypress-project your-app-name-e2e --baseUrl=http://localhost:4200
Replace your-app-name with the app's name as defined in your workspace.json file.
Testing Applications
Run nx e2e frontend-e2e to execute e2e tests with Cypress.
You can run your e2e test against a production build with the --prod flag
nx e2e frontend-e2e --prod
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/apps/frontend/screenshots and dist/cypress/apps/frontend/videos.
Watching for Changes (Headed Mode)
With, nx e2e frontend-e2e --watch Cypress will start in headed mode where you can see your application being tested.
Running Cypress with --watch is a great way to enhance dev workflow - you can build up test files with the application running and Cypress will re-run those tests as you enhance and add to the suite.
nx e2e frontend-e2e --prod
Specifying a Custom Url to Test
The baseUrl property provides you the ability to test an application hosted on a specific domain.
nx e2e frontend-e2e --baseUrl=https://frontend.com
If no
baseUrland nodevServerTargetare provided, Cypress will expect to have thebaseUrlproperty in the cypress config file, or will error.
Using cypress.config.ts
If you need to fine tune your Cypress setup, you can do so by modifying cypress.config.ts in the project root. For instance, you can easily add your projectId to save all the screenshots and videos into your Cypress dashboard. The complete configuration is documented on the official website.
Environment Variables
If you're needing to pass a variable to cypress that you wish to not commit to your repository, i.e. API keys, or dynamic values based on configurations, i.e. API Urls. This is where Cypress environment variables can be used.
There are a handful of ways to pass environment variables to Cypress, but the most common is going to be via the cypress.env.json file, the env executor option for cypress or the commandline.
Create a cypress.env.json file in the projects root i.e. apps/my-cool-app-e2e/cypress.env.json. Cypress will automatically pick up this file. This method is helpful for configurations that you want to not commit. Just don't forget to add the file to the .gitignore and add documentation so people in your repo know what values to popluate in their local copy of the cypress.env.json file.
Using @nrwl/cypress:cypress env executor option is a good way to add values you want to define that you don't mine commit to the repository, such as a base API url. You can leverage target configurations to define different values as well.
Optionally, you can pass environment variables via the commandline with the --env flag.
nx e2e frontend-e2e --env.API_URL="https://api.my-nx-website.com" --env.API_KEY="abc-123"