- Ensure your vendor directory is populated (e.g. by running `composer install`)
- If you're running PHP 7.0 or greater you will need to upgrade PHPUnit with `composer run-script drupal-phpunit-upgrade`
- Install [Node.js](https://nodejs.org/en/download/) and [yarn](https://yarnpkg.com/en/docs/install). The versions required are specificed inside core/package.json in the `engines` field
- Configure the nightwatch settings by copying `.env.example` to `.env` and editing as necessary.
- Ensure you have a web server running (as instructed in `.env`)
- Again inside the `core` folder, run `yarn test:nightwatch` to run the tests. By default this will output reports to `core/reports`
- Nightwatch will run tests for core, as well as contrib and custom modules and themes. It will search for tests located under folders with the pattern `**/tests/**/Nightwatch/(Tests|Commands|Assertions)`
- To run only core tests, run `yarn test:nightwatch --tag core`
- To skip running core tests, run `yarn test:nightwatch --skiptags core`
- To run a single test, run e.g. `yarn test:nightwatch tests/Drupal/Nightwatch/Tests/exampleTest.js`
Nightwatch tests can be placed in any folder with the pattern `**/tests/**/Nightwatch/(Tests|Commands|Assertions)`. For example:
```
tests/Nightwatch/Tests
src/tests/Nightwatch/Tests
tests/src/Nightwatch/Tests
tests/Nightwatch/Commands
```
It's helpful to follow existing patterns for test placement, so for the action module they would go in `core/modules/action/tests/src/Nightwatch`.
The Nightwatch configuration, as well as global tests, commands, and assertions which span many modules/systems, are located in `core/tests/Drupal/Nightwatch`.
If your core directory is located in a subfolder (e.g. `docroot`), then you can edit the search directory in `.env` to pick up tests outside of your Drupal directory.
Tests outside of the `core` folder will run in the version of node you have installed. If you want to transpile with babel (e.g. to use `import` statements) outside of core,
then add your own babel config to the root of your project. For example, if core is located under `docroot/core`, then you could run `yarn add babel-preset-env` inside
`docroot`, then copy the babel settings from `docroot/core/package.json` into `docroot/package.json`.