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eslint-plugin-jest

ESLint plugin for Jest

## Installation ``` $ yarn add --dev eslint eslint-plugin-jest ``` **Note:** If you installed ESLint globally then you must also install `eslint-plugin-jest` globally. ## Usage Add `jest` to the plugins section of your `.eslintrc` configuration file. You can omit the `eslint-plugin-` prefix: ```json { "plugins": ["jest"] } ``` Then configure the rules you want to use under the rules section. ```json { "rules": { "jest/no-disabled-tests": "warn", "jest/no-focused-tests": "error", "jest/no-identical-title": "error", "jest/prefer-to-have-length": "warn", "jest/valid-expect": "error" } } ``` You can also whitelist the environment variables provided by Jest by doing: ```json { "env": { "jest/globals": true } } ``` ## Shareable configurations ### Recommended This plugin exports a recommended configuration that enforces good testing practices. To enable this configuration use the `extends` property in your `.eslintrc` config file: ```json { "extends": ["plugin:jest/recommended"] } ``` ### Style This plugin also exports a configuration named `style`, which adds some stylistic rules, such as `prefer-to-be-null`, which enforces usage of `toBeNull` over `toBe(null)`. To enable this configuration use the `extends` property in your `.eslintrc` config file: ```json { "extends": ["plugin:jest/style"] } ``` See [ESLint documentation](http://eslint.org/docs/user-guide/configuring#extending-configuration-files) for more information about extending configuration files. ### All If you want to enable all rules instead of only some you can do so by adding the `all` configuration to your `.eslintrc` config file: ```json { "extends": ["plugin:jest/all"] } ``` While the `recommended` and `style` configurations only change in major versions the `all` configuration may change in any release and is thus unsuited for installations requiring long-term consistency. ## Rules | Rule | Description | Configurations | Fixable | | ------------------------------ | ----------------------------------------------------------------- | ---------------- | ------------------- | | [consistent-test-it][] | Enforce consistent test or it keyword | | ![fixable-green][] | | [expect-expect][] | Enforce assertion to be made in a test body | ![recommended][] | | | [lowercase-name][] | Disallow capitalized test names | | ![fixable-green][] | | [no-alias-methods][] | Disallow alias methods | ![style][] | ![fixable-green][] | | [no-commented-out-tests][] | Disallow commented out tests | ![recommended][] | | | [no-disabled-tests][] | Disallow disabled tests | ![recommended][] | | | [no-duplicate-hooks][] | Disallow duplicate hooks within a `describe` block | | | | [no-expect-resolves][] | Disallow using `expect().resolves` | | | | [no-export][] | Disallow export from test files | ![recommended][] | | | [no-focused-tests][] | Disallow focused tests | ![recommended][] | | | [no-hooks][] | Disallow setup and teardown hooks | | | | [no-identical-title][] | Disallow identical titles | ![recommended][] | | | [no-if][] | Disallow conditional logic | | | | [no-jasmine-globals][] | Disallow Jasmine globals | ![recommended][] | ![fixable-yellow][] | | [no-jest-import][] | Disallow importing `jest` | ![recommended][] | | | [no-large-snapshots][] | Disallow large snapshots | | | | [no-mocks-import][] | Disallow manually importing from `__mocks__` | ![recommended][] | | | [no-standalone-expect][] | Prevents `expect` statements outside of a `test` or `it` block | ![recommended][] | | | [no-test-callback][] | Using a callback in asynchronous tests | ![recommended][] | ![fixable-green][] | | [no-test-prefixes][] | Disallow using `f` & `x` prefixes to define focused/skipped tests | ![recommended][] | ![fixable-green][] | | [no-test-return-statement][] | Disallow explicitly returning from tests | | | | [no-truthy-falsy][] | Disallow using `toBeTruthy()` & `toBeFalsy()` | | | | [no-try-expect][] | Prevent `catch` assertions in tests | ![recommended][] | | | [prefer-called-with][] | Suggest using `toBeCalledWith()` OR `toHaveBeenCalledWith()` | | | | [prefer-expect-assertions][] | Suggest using `expect.assertions()` OR `expect.hasAssertions()` | | | | [prefer-hooks-on-top][] | Suggest to have all hooks at top-level before tests | | | | [prefer-inline-snapshots][] | Suggest using `toMatchInlineSnapshot()` | | ![fixable-green][] | | [prefer-spy-on][] | Suggest using `jest.spyOn()` | | ![fixable-green][] | | [prefer-strict-equal][] | Suggest using `toStrictEqual()` | | ![fixable-green][] | | [prefer-to-be-null][] | Suggest using `toBeNull()` | ![style][] | ![fixable-green][] | | [prefer-to-be-undefined][] | Suggest using `toBeUndefined()` | ![style][] | ![fixable-green][] | | [prefer-to-contain][] | Suggest using `toContain()` | ![style][] | ![fixable-green][] | | [prefer-to-have-length][] | Suggest using `toHaveLength()` | ![style][] | ![fixable-green][] | | [prefer-todo][] | Suggest using `test.todo()` | | ![fixable-green][] | | [require-top-level-describe][] | Require a top-level `describe` block | | | | [require-to-throw-message][] | Require that `toThrow()` and `toThrowError` includes a message | | | | [valid-describe][] | Enforce valid `describe()` callback | ![recommended][] | | | [valid-expect-in-promise][] | Enforce having return statement when testing with promises | ![recommended][] | | | [valid-expect][] | Enforce valid `expect()` usage | ![recommended][] | | | [valid-title][] | Enforce valid titles for jest blocks | | | ## Credit - [eslint-plugin-mocha](https://github.com/lo1tuma/eslint-plugin-mocha) - [eslint-plugin-jasmine](https://github.com/tlvince/eslint-plugin-jasmine) ## Related Projects ### eslint-plugin-jest-formatting This project aims to provide formatting rules (auto-fixable where possible) to ensure consistency and readability in jest test suites. https://github.com/dangreenisrael/eslint-plugin-jest-formatting [consistent-test-it]: docs/rules/consistent-test-it.md [expect-expect]: docs/rules/expect-expect.md [lowercase-name]: docs/rules/lowercase-name.md [no-alias-methods]: docs/rules/no-alias-methods.md [no-commented-out-tests]: docs/rules/no-commented-out-tests.md [no-disabled-tests]: docs/rules/no-disabled-tests.md [no-duplicate-hooks]: docs/rules/no-duplicate-hooks.md [no-expect-resolves]: docs/rules/no-expect-resolves.md [no-export]: docs/rules/no-export.md [no-focused-tests]: docs/rules/no-focused-tests.md [no-hooks]: docs/rules/no-hooks.md [no-identical-title]: docs/rules/no-identical-title.md [no-if]: docs/rules/no-if.md [no-jasmine-globals]: docs/rules/no-jasmine-globals.md [no-jest-import]: docs/rules/no-jest-import.md [no-large-snapshots]: docs/rules/no-large-snapshots.md [no-mocks-import]: docs/rules/no-mocks-import.md [no-standalone-expect]: docs/rules/no-standalone-expect.md [no-test-callback]: docs/rules/no-test-callback.md [no-test-prefixes]: docs/rules/no-test-prefixes.md [no-test-return-statement]: docs/rules/no-test-return-statement.md [no-truthy-falsy]: docs/rules/no-truthy-falsy.md [no-try-expect]: docs/rules/no-try-expect.md [prefer-called-with]: docs/rules/prefer-called-with.md [prefer-expect-assertions]: docs/rules/prefer-expect-assertions.md [prefer-inline-snapshots]: docs/rules/prefer-inline-snapshots.md [prefer-hooks-on-top]: docs/rules/prefer-hooks-on-top.md [prefer-spy-on]: docs/rules/prefer-spy-on.md [prefer-strict-equal]: docs/rules/prefer-strict-equal.md [prefer-to-be-null]: docs/rules/prefer-to-be-null.md [prefer-to-be-undefined]: docs/rules/prefer-to-be-undefined.md [prefer-to-contain]: docs/rules/prefer-to-contain.md [prefer-to-have-length]: docs/rules/prefer-to-have-length.md [prefer-todo]: docs/rules/prefer-todo.md [require-top-level-describe]: docs/rules/require-top-level-describe.md [require-to-throw-message]: docs/rules/require-to-throw-message.md [valid-describe]: docs/rules/valid-describe.md [valid-expect-in-promise]: docs/rules/valid-expect-in-promise.md [valid-expect]: docs/rules/valid-expect.md [valid-title]: docs/rules/valid-title.md [fixable-green]: https://img.shields.io/badge/-fixable-green.svg [fixable-yellow]: https://img.shields.io/badge/-fixable-yellow.svg [recommended]: https://img.shields.io/badge/-recommended-lightgrey.svg [style]: https://img.shields.io/badge/-style-blue.svg