Developing Components: Testing

If you choose the testing option in the project generator it will scaffold some example tests for your component.

Web Test Runner

We recommend @web/test-runner for testing web components. It's based on @web/dev-server, following the same approach using native es modules, and runs tests in a real browser.

Running the tests

To run the tests, execute this command:

npm run test

This will run the tests in a locally installed Chrome browser. There are many other browser options in Web Test Runner as well.

To run the tests in watch mode, execute this command:

npm run test:watch

This will keep the test runner open. Editing files will re-run the associated tests.

Step by step guide

Follow this guide for a full step by step guide on using Web Test Runner