+++ /dev/null
----
-title: Unit Tests
-layout: doc
-eleventyNavigation:
- key: run the tests
- parent: developer guide
- title: Run the Tests
- order: 3
-
----
-
-Most parts of ESLint have unit tests associated with them. Unit tests are written using [Mocha](https://mochajs.org/) and are required when making contributions to ESLint. You'll find all of the unit tests in the `tests` directory.
-
-When you first get the source code, you need to run `npm install` once initially to set ESLint for development. Once you've done that, you can run the tests via:
-
-```shell
-npm test
-```
-
-This automatically starts Mocha and runs all tests in the `tests` directory. You need only add yours and it will automatically be picked up when running tests.
-
-## Running Individual Tests
-
-If you want to quickly run just one test file, you can do so by running Mocha directly and passing in the filename. For example:
-
-```shell
-npm run test:cli tests/lib/rules/no-undef.js
-```
-
-If you want to run just one or a subset of `RuleTester` test cases, add `only: true` to each test case or wrap the test case in `RuleTester.only(...)` to add it automatically:
-
-```js
-ruleTester.run("my-rule", myRule, {
- valid: [
- RuleTester.only("const valid = 42;"),
- // Other valid cases
- ],
- invalid: [
- {
- code: "const invalid = 42;",
- only: true,
- },
- // Other invalid cases
- ]
-})
-```
-
-Running individual tests is useful when you're working on a specific bug and iterating on the solution. You should be sure to run `npm test` before submitting a pull request. `npm test` uses Mocha's `--forbid-only` option to prevent `only` tests from passing full test runs.
-
-## More Control on Unit Testing
-
-`npm run test:cli` is an alias of the Mocha cli in `./node_modules/.bin/mocha`. [Options](https://mochajs.org/#command-line-usage) are available to be provided to help to better control the test to run.
-
-The default timeout for tests in `npm test` is 10000ms. You may change the timeout by providing `ESLINT_MOCHA_TIMEOUT` environment variable, for example:
-
-```shell
-ESLINT_MOCHA_TIMEOUT=20000 npm test
-```