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Configuring Jest

Настройки Jest можно задать в файле package.json вашего проекта, через файл jest.config.js или с параметром --config <path/to/file.js|json>. Если вы хотите использовать package.json для хранения конфигурации Jest, то необходимо использовать параметр "jest" на верхнем уровне, чтобы Jest знал как найти ваши настройки:

{
  "name": "my-project",
  "jest": {
    "verbose": true
  }
}

Или с помощью JavaScript:

// jest.config.js
module.exports = {
  verbose: true,
};

Пожалуйста, имейте в виду, что полученная конфигурация должна быть JSON-сериализируемой.

При использовании опции --config, json-файл не должен содержать ключ "jest":

{
  "bail": true,
  "verbose": true
}

Параметры

These options let you control Jest's behavior in your package.json file. The Jest philosophy is to work great by default, but sometimes you just need more configuration power.

Значения по умолчанию

Вы можете получить настройки Jest по умолчанию, чтобы расширить их, если понадобится:

// jest.config.js
const {defaults} = require('jest-config');
module.exports = {
  // ...
  moduleFileExtensions: [...defaults.moduleFileExtensions, 'ts', 'tsx'],
  // ...
};

Справка

automock [boolean]

Значение по умолчанию: false

This option tells Jest that all imported modules in your tests should be mocked automatically. All modules used in your tests will have a replacement implementation, keeping the API surface.

Пример:

// utils.js
export default {
  authorize: () => {
    return 'token';
  },
  isAuthorized: secret => secret === 'wizard',
};

//__tests__/automocking.test.js
import utils from '../utils';

test('if utils mocked automatically', () => {
  // Public methods of `utils` are now mock functions
  expect(utils.authorize.mock).toBeTruthy();
  expect(utils.isAuthorized.mock).toBeTruthy();

  // You can provide them with your own implementation
  // or pass the expected return value
  utils.authorize.mockReturnValue('mocked_token');
  utils.isAuthorized.mockReturnValue(true);

  expect(utils.authorize()).toBe('mocked_token');
  expect(utils.isAuthorized('not_wizard')).toBeTruthy();
});

Note: Node modules are automatically mocked when you have a manual mock in place (e.g.: __mocks__/lodash.js). More info here.

Note: Core modules, like fs, are not mocked by default. They can be mocked explicitly, like jest.mock('fs').

bail [boolean]

Значение по умолчанию: false

By default, Jest runs all tests and produces all errors into the console upon completion. The bail config option can be used here to have Jest stop running tests after the first failure.

browser [boolean]

Значение по умолчанию: false

Учитывать Browserify "browser" поле в package.json при разрешении модулей. Некоторые модули экспортируют различные версии основываясь на том оперируют ли он в Node или в браузере.

cacheDirectory [string]

По умолчанию: «/tmp/<путь>»

Директория, в которой Jest следует хранить кэшированные сведения о зависимостях.

Jest предпринимает попытку единожды просканировать дерево зависимостей (предварительно) и сохранить кэш с данными о них, чтобы облегчить проход файловой системы, который происходит при запуске тестов. Данная опция позволяет разработчику указать где именно в файловой системе следует хранить кэшированные данные.

clearMocks [boolean]

Значение по умолчанию: false

Automatically clear mock calls and instances before every test. Equivalent to calling jest.clearAllMocks() before each test. This does not remove any mock implementation that may have been provided.

collectCoverage [boolean]

Значение по умолчанию: false

Указывает следует ли собирать информацию о тестовом покрытии при выполнении тестов. Из-за того, что данный процесс вносит информацию о покрытии во все выполненные файлы, ваши тесты могут быть существенно замедлены.

collectCoverageFrom [array]

Значение по умолчанию: undefined

An array of glob patterns indicating a set of files for which coverage information should be collected. If a file matches the specified glob pattern, coverage information will be collected for it even if no tests exist for this file and it's never required in the test suite.

Пример:

{
  "collectCoverageFrom": [
    "**/*.{js,jsx}",
    "!**/node_modules/**",
    "!**/vendor/**"
  ]
}

This will collect coverage information for all the files inside the project's rootDir, except the ones that match **/node_modules/** or **/vendor/**.

Примечание: Для работы этой опции требуется установить опцию collectCoverage в значение true или запустить Jest с ключом --coverage.

Help: If you are seeing coverage output such as...

=============================== Coverage summary ===============================
Statements   : Unknown% ( 0/0 )
Branches     : Unknown% ( 0/0 )
Functions    : Unknown% ( 0/0 )
Lines        : Unknown% ( 0/0 )
================================================================================
Jest: Coverage data for global was not found.

Most likely your glob patterns are not matching any files. Refer to the micromatch documentation to ensure your globs are compatible.

coverageDirectory [string]

Значение по умолчанию: undefined

Каталог, куда Jest будет сохранять файлы с информацией о покрытии.

coveragePathIgnorePatterns [массив<string>]

Значение по умолчанию: ["/node_modules/"]

An array of regexp pattern strings that are matched against all file paths before executing the test. If the file path matches any of the patterns, coverage information will be skipped.

Эти строки шаблонов проверяют на соответствие полный путь. Use the <rootDir> string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Пример: [«<rootDir>/build/», «<rootDir>/node_modules/»].

coverageReporters [массив<string>]

Default: ["json", "lcov", "text", "clover"]

A list of reporter names that Jest uses when writing coverage reports. Any istanbul reporter can be used.

Note: Setting this option overwrites the default values. Add "text" or "text-summary" to see a coverage summary in the console output.

coverageThreshold [object]

Значение по умолчанию: undefined

Эта опция используется для настройки минимального значения порога для результатов покрытия. Thresholds can be specified as global, as a glob, and as a directory or file path. Если пороги не будут выполнены, шутка не удастся. Thresholds specified as a positive number are taken to be the minimum percentage required. Thresholds specified as a negative number represent the maximum number of uncovered entities allowed.

For example, with the following configuration jest will fail if there is less than 80% branch, line, and function coverage, or if there are more than 10 uncovered statements:

{
  ...
  "jest": {
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": -10
      }
    }
  }
}

If globs or paths are specified alongside global, coverage data for matching paths will be subtracted from overall coverage and thresholds will be applied independently. Пороги для globs применяются ко всем файлам, соответствующим glob. If the file specified by path is not found, an error is returned.

Например, со следующей конфигурацией:

{
  ...
  "jest": {
    "coverageThreshold": {
      "global": {
        "branches": 50,
        "functions": 50,
        "lines": 50,
        "statements": 50
      },
      "./src/components/": {
        "branches": 40,
        "statements": 40
      },
      "./src/reducers/**/*.js": {
        "statements": 90
      },
      "./src/api/very-important-module.js": {
        "branches": 100,
        "functions": 100,
        "lines": 100,
        "statements": 100
      }
    }
  }
}

Шутка потерпит неудачу, если:

  • The ./src/components directory has less than 40% branch or statement coverage.
  • One of the files matching the ./src/reducers/**/*.js glob has less than 90% statement coverage.
  • Тот ./грц/по Api/очень-важный-модуль.js файл имеет менее 100% покрытия.
  • Каждый оставшийся файл вместе имеет менее 50% покрытия глобальный.

displayName [string]

значение по умолчанию: undefined

Allows for a label to be printed alongside a test while it is running. This becomes more useful in multi-project repositories where there can be many jest configuration files. This visually tells which project a test belongs to.

errorOnDeprecated [boolean]

Значение по умолчанию: false

Make calling deprecated APIs throw helpful error messages. Useful for easing the upgrade process.

forceCoverageMatch [массив<string>]

Default: ['']

Test files are normally ignored from collecting code coverage. With this option, you can overwrite this behavior and include otherwise ignored files in code coverage.

For example, if you have tests in source files named with .t.js extension as following:

// sum.t.js

export function sum(a, b) {
  return a + b;
}

if (process.env.NODE_ENV === 'test') {
  test('sum', () => {
    expect(sum(1, 2)).toBe(3);
  });
}

You can collect coverage from those files with setting forceCoverageMatch.

{
  ...
  "jest": {
    "forceCoverageMatch": ["**/*.t.js"]
  }
}

globals [object]

Значение по умолчанию: {}

Набор глобальных переменных, которые необходимы во всех тестовых средах.

Например, следующий код инициализирует глобальную переменную __DEV__ в true во всех тестовых средах:

{
  ...
  "jest": {
    "globals": {
      "__DEV__": true
    }
  }
}

Обратите внимание, что, если значение глобальной переменной будет ссылочным типом (к примеру объект или массив), и где-то в коде это значение будет изменяться в момент, когда тесты запущены, то данные изменения *не * будут сохранены в тестовых прогонах для других тестовых файлов. In addition, the globals object must be json-serializable, so it can't be used to specify global functions. For that, you should use setupFiles.

globalSetup [string]

Значение по умолчанию: undefined

This option allows the use of a custom global setup module which exports an async function that is triggered once before all test suites. This function gets Jest's globalConfig object as a parameter.

globalTeardown [string]

Значение по умолчанию: undefined

This option allows the use of a custom global teardown module which exports an async function that is triggered once after all test suites. This function gets Jest's globalConfig object as a parameter.

haste [object]

Значение по умолчанию: undefined

This will be used to configure the behavior of jest-haste-map, Jest's internal file crawler/cache system. The following options are supported:

type HasteConfig = {
  // Whether to hash files using SHA-1.
  computeSha1?: boolean;
  // The platform to use as the default, e.g. 'ios'.
  defaultPlatform?: string | null;
  // Path to a custom implementation of Haste.
  hasteImplModulePath?: string;
  // All platforms to target, e.g ['ios', 'android'].
  platforms?: Array<string>;
  // Whether to throw on error on module collision.
  throwOnModuleCollision?: boolean;
};

moduleDirectories [массив<string>]

Значение по умолчанию: ["node_modules"]

Массив имен каталогов для рекурсивного поиска местоположения импортируемых модулей. Setting this option will override the default, if you wish to still search node_modules for packages include it along with any other options: ["node_modules", "bower_components"]

moduleFileExtensions [массив<string>]

Значение по умолчанию: ["js", "json", "jsx", "node"]

An array of file extensions your modules use. If you require modules without specifying a file extension, these are the extensions Jest will look for, in left-to-right order.

If you are using TypeScript, you will want to add "ts" and/or "tsx" to the above default. Where you place these is up to you - we recommend placing the extensions most commonly used in your project on the left.

moduleNameMapper [object<string, string>]

Значение по умолчанию: null

A map from regular expressions to module names that allow to stub out resources, like images or styles with a single module.

Modules that are mapped to an alias are unmocked by default, regardless of whether automocking is enabled or not.

Use <rootDir> string token to refer to rootDir value if you want to use file paths.

Additionally, you can substitute captured regex groups using numbered backreferences.

Пример:

{
  "moduleNameMapper": {
    "^image![a-zA-Z0-9$_-]+$": "GlobalImageStub",
    "^[./a-zA-Z0-9$_-]+\\.png$": "<rootDir>/RelativeImageStub.js",
    "module_name_(.*)": "<rootDir>/substituted_module_$1.js"
  }
}

The order in which the mappings are defined matters. Patterns are checked one by one until one fits. The most specific rule should be listed first.

Note: If you provide module name without boundaries ^$ it may cause hard to spot errors. E.g. relay will replace all modules which contain relay as a substring in its name: relay, react-relay and graphql-relay will all be pointed to your stub.

modulePathIgnorePatterns [массив<string>]

Значение по умолчанию: []

An array of regexp pattern strings that are matched against all module paths before those paths are to be considered 'visible' to the module loader. If a given module's path matches any of the patterns, it will not be require()-able in the test environment.

Эти строки шаблонов проверяют на соответствие полный путь. Use the <rootDir> string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Example: ["<rootDir>/build/"].

modulePaths [массив<string>]

Значение по умолчанию: []

An alternative API to setting the NODE_PATH env variable, modulePaths is an array of absolute paths to additional locations to search when resolving modules. Use the <rootDir> string token to include the path to your project's root directory. Example: ["<rootDir>/app/"].

notify [boolean]

Значение по умолчанию: false

Активирует уведомления для результатов теста.

Beware: Jest uses node-notifier to display desktop notifications. On Windows, it creates a new start menu entry on the first use and not display the notification. Notifications will be properly displayed on subsequent runs

notifyMode [string]

Default: always

Specifies notification mode. Requires notify: true.

Modes

  • always: always send a notification.
  • failure: send a notification when tests fail.
  • success: send a notification when tests pass.
  • change: send a notification when the status changed.
  • success-change: send a notification when tests pass or once when it fails.
  • failure-change: send a notification when tests fail or once when it passes.

preset [string]

Значение по умолчанию: undefined

A preset that is used as a base for Jest's configuration. A preset should point to an npm module that has a jest-preset.json or jest-preset.js file at the root.

For example, this preset foo-bar/jest-preset.js will be configured as follows:

{
  "preset": "foo-bar"
}

Presets may also be relative to filesystem paths.

{
  "preset": "./node_modules/foo-bar/jest-preset.js"
}

prettierPath [string]

Default: 'prettier'

Sets the path to the prettier node module used to update inline snapshots.

projects [массив<string | projectconfig>]

Значение по умолчанию: undefined

When the projects configuration is provided with an array of paths or glob patterns, Jest will run tests in all of the specified projects at the same time. This is great for monorepos or when working on multiple projects at the same time.

{
  "projects": ["<rootDir>", "<rootDir>/examples/*"]
}

This example configuration will run Jest in the root directory as well as in every folder in the examples directory. You can have an unlimited amount of projects running in the same Jest instance.

The projects feature can also be used to run multiple configurations or multiple runners. For this purpose, you can pass an array of configuration objects. For example, to run both tests and ESLint (via jest-runner-eslint) in the same invocation of Jest:

{
  "projects": [
    {
      "displayName": "test"
    },
    {
      "displayName": "lint",
      "runner": "jest-runner-eslint",
      "testMatch": ["<rootDir>/**/*.js"]
    }
  ]
}

Note: When using multi-project runner, it's recommended to add a displayName for each project. This will show the displayName of a project next to its tests.

reporters [массив<modulename | [modulename, options]>]

Значение по умолчанию: undefined

Use this configuration option to add custom reporters to Jest. A custom reporter is a class that implements onRunStart, onTestStart, onTestResult, onRunComplete methods that will be called when any of those events occurs.

If custom reporters are specified, the default Jest reporters will be overridden. To keep default reporters, default can be passed as a module name.

This will override default reporters:

{
  "reporters": ["<rootDir>/my-custom-reporter.js"]
}

This will use custom reporter in addition to default reporters that Jest provides:

{
  "reporters": ["default", "<rootDir>/my-custom-reporter.js"]
}

Additionally, custom reporters can be configured by passing an options object as a second argument:

{
  "reporters": [
    "default",
    ["<rootDir>/my-custom-reporter.js", {"banana": "yes", "pineapple": "no"}]
  ]
}

Custom reporter modules must define a class that takes a GlobalConfig and reporter options as constructor arguments:

Example reporter:

// my-custom-reporter.js
class MyCustomReporter {
  constructor(globalConfig, options) {
    this._globalConfig = globalConfig;
    this._options = options;
  }

  onRunComplete(contexts, results) {
    console.log('Custom reporter output:');
    console.log('GlobalConfig: ', this._globalConfig);
    console.log('Options: ', this._options);
  }
}

module.exports = MyCustomReporter;

Custom reporters can also force Jest to exit with non-0 code by returning an Error from getLastError() methods

class MyCustomReporter {
  // ...
  getLastError() {
    if (this._shouldFail) {
      return new Error('my-custom-reporter.js reported an error');
    }
  }
}

For the full list of methods and argument types see Reporter interface in packages/jest-reporters/src/types.ts

resetMocks [boolean]

Значение по умолчанию: false

Automatically reset mock state before every test. Equivalent to calling jest.resetAllMocks() before each test. This will lead to any mocks having their fake implementations removed but does not restore their initial implementation.

resetModules [boolean]

Значение по умолчанию: false

By default, each test file gets its own independent module registry. Enabling resetModules goes a step further and resets the module registry before running each individual test. This is useful to isolate modules for every test so that the local module state doesn't conflict between tests. This can be done programmatically using jest.resetModules().

resolver [string]

Значение по умолчанию: undefined

This option allows the use of a custom resolver. This resolver must be a node module that exports a function expecting a string as the first argument for the path to resolve and an object with the following structure as the second argument:

{
  "basedir": string,
  "browser": boolean,
  "extensions": [string],
  "moduleDirectory": [string],
  "paths": [string],
  "rootDir": [string]
}

The function should either return a path to the module that should be resolved or throw an error if the module can't be found.

restoreMocks [boolean]

Значение по умолчанию: false

Automatically restore mock state before every test. Equivalent to calling jest.restoreAllMocks() before each test. This will lead to any mocks having their fake implementations removed and restores their initial implementation.

rootDir [string]

Default: The root of the directory containing your Jest config file or the package.json or the pwd if no package.json is found

The root directory that Jest should scan for tests and modules within. If you put your Jest config inside your package.json and want the root directory to be the root of your repo, the value for this config param will default to the directory of the package.json.

Oftentimes, you'll want to set this to 'src' or 'lib', corresponding to where in your repository the code is stored.

Note that using '<rootDir>' as a string token in any other path-based config settings will refer back to this value. So, for example, if you want your setupFiles config entry to point at the env-setup.js file at the root of your project, you could set its value to ["<rootDir>/env-setup.js"].

roots [массив<string>]

Default: ["<rootDir>"]

A list of paths to directories that Jest should use to search for files in.

There are times where you only want Jest to search in a single sub-directory (such as cases where you have a src/ directory in your repo), but prevent it from accessing the rest of the repo.

Note: While rootDir is mostly used as a token to be re-used in other configuration options, roots is used by the internals of Jest to locate test files and source files. This applies also when searching for manual mocks for modules from node_modules (__mocks__ will need to live in one of the roots).

Note: By default, roots has a single entry <rootDir> but there are cases where you may want to have multiple roots within one project, for example roots: ["<rootDir>/src/", "<rootDir>/tests/"].

runner [string]

Default: "jest-runner"

This option allows you to use a custom runner instead of Jest's default test runner. Examples of runners include:

To write a test-runner, export a class with which accepts globalConfig in the constructor, and has a runTests method with the signature:

async runTests(
  tests: Array<Test>,
  watcher: TestWatcher,
  onStart: OnTestStart,
  onResult: OnTestSuccess,
  onFailure: OnTestFailure,
  options: TestRunnerOptions,
): Promise<void>

If you need to restrict your test-runner to only run in serial rather than being executed in parallel your class should have the property isSerial to be set as true.

setupFiles [array]

Значение по умолчанию: []

A list of paths to modules that run some code to configure or set up the testing environment. Each setupFile will be run once per test file. Since every test runs in its own environment, these scripts will be executed in the testing environment immediately before executing the test code itself.

It's also worth noting that setupFiles will execute before setupTestFrameworkScriptFile.

setupTestFrameworkScriptFile [string]

Значение по умолчанию: undefined

The path to a module that runs some code to configure or set up the testing framework before each test file in the suite is executed. Since setupFiles executes before the test framework is installed in the environment, this script file presents you the opportunity of running some code immediately after the test framework has been installed in the environment.

If you want a path to be relative to the root directory of your project, please include <rootDir> inside a path's string, like "<rootDir>/a-configs-folder".

For example, Jest ships with several plug-ins to jasmine that work by monkey-patching the jasmine API. If you wanted to add even more jasmine plugins to the mix (or if you wanted some custom, project-wide matchers for example), you could do so in these modules.

Example setupTestFrameworkScriptFile in a jest.config.js:

module.exports = {
  setupTestFrameworkScriptFile: './jest.setup.js',
};

Example jest.setup.js file

jest.setTimeout(10000); // in milliseconds

snapshotSerializers [массив<string>]

Значение по умолчанию: []

A list of paths to snapshot serializer modules Jest should use for snapshot testing.

Jest has default serializers for built-in JavaScript types, HTML elements (Jest 20.0.0+), ImmutableJS (Jest 20.0.0+) and for React elements. See snapshot test tutorial for more information.

Example serializer module:

// my-serializer-module
module.exports = {
  serialize(val, config, indentation, depth, refs, printer) {
    return 'Pretty foo: ' + printer(val.foo);
  },

  test(val) {
    return val && val.hasOwnProperty('foo');
  },
};

printer is a function that serializes a value using existing plugins.

To use my-serializer-module as a serializer, configuration would be as follows:

{
  ...
  "jest": {
    "snapshotSerializers": ["my-serializer-module"]
  }
}

Finally tests would look as follows:

test(() => {
  const bar = {
    foo: {
      x: 1,
      y: 2,
    },
  };

  expect(bar).toMatchSnapshot();
});

Rendered snapshot:

Pretty foo: Object {
  "x": 1,
  "y": 2,
}

To make a dependency explicit instead of implicit, you can call expect.addSnapshotSerializer to add a module for an individual test file instead of adding its path to snapshotSerializers in Jest configuration.

More about serializers API can be found here.

testEnvironment [string]

Значение по умолчанию: "jsdom"

The test environment that will be used for testing. The default environment in Jest is a browser-like environment through jsdom. If you are building a node service, you can use the node option to use a node-like environment instead.

By adding a @jest-environment docblock at the top of the file, you can specify another environment to be used for all tests in that file:

/**
 * @jest-environment jsdom
 */

test('use jsdom in this test file', () => {
  const element = document.createElement('div');
  expect(element).not.toBeNull();
});

You can create your own module that will be used for setting up the test environment. The module must export a class with setup, teardown and runScript methods. You can also pass variables from this module to your test suites by assigning them to this.global object – this will make them available in your test suites as global variables.

To use this class as your custom environment, refer to it by its full path within the project. For example, if your class is stored in my-custom-environment.js in some subfolder of your project, then the annotation might looke like this:

/**
 * @jest-environment ./src/test/my-custom-environment
 */

Note: TestEnvironment is sandboxed. Each test suite will trigger setup/teardown in their own TestEnvironment.

Пример:

// my-custom-environment
const NodeEnvironment = require('jest-environment-node');

class CustomEnvironment extends NodeEnvironment {
  constructor(config, context) {
    super(config, context);
    this.testPath = context.testPath;
    this.docblockPragmas = context.docblockPragmas;
  }

  async setup() {
    await super.setup();
    await someSetupTasks(this.testPath);
    this.global.someGlobalObject = createGlobalObject();

    // Will trigger if docblock contains @my-custom-pragma my-pragma-value
    if (this.docblockPragmas['my-custom-pragma'] === 'my-pragma-value') {
      // ...
    }
  }

  async teardown() {
    this.global.someGlobalObject = destroyGlobalObject();
    await someTeardownTasks();
    await super.teardown();
  }

  runScript(script) {
    return super.runScript(script);
  }
}

module.exports = CustomEnvironment;

// my-test-suite
/**
 * @jest-environment ./my-custom-environment
 */
let someGlobalObject;

beforeAll(() => {
  someGlobalObject = global.someGlobalObject;
});

Note: Jest comes with JSDOM@11 by default. Due to JSDOM 12 and newer dropping support for Node 6, Jest is unable to upgrade for the time being. However, you can install a custom testEnvironment with whichever version of JSDOM you want. E.g. jest-environment-jsdom-thirteen, which has JSDOM@13.

testEnvironmentOptions [Object]

Значение по умолчанию: {}

Test environment options that will be passed to the testEnvironment. The relevant options depend on the environment. For example, you can override options given to jsdom such as {userAgent: "Agent/007"}.

testFailureExitCode [number]

Default: 1

The exit code Jest returns on test failure.

Note: This does not change the exit code in the case of Jest errors (e.g. invalid configuration).

testMatch [массив<string>]

(default: [ "**/__tests__/**/*.js?(x)", "**/?(*.)+(spec|test).js?(x)" ])

The glob patterns Jest uses to detect test files. By default it looks for .js and .jsx files inside of __tests__ folders, as well as any files with a suffix of .test or .spec (e.g. Component.test.js or Component.spec.js). It will also find files called test.js or spec.js.

See the micromatch package for details of the patterns you can specify.

See also testRegex [string], but note that you cannot specify both options.

testPathIgnorePatterns [массив<string>]

Значение по умолчанию: ["/node_modules/"]

An array of regexp pattern strings that are matched against all test paths before executing the test. If the test path matches any of the patterns, it will be skipped.

Эти строки шаблонов проверяют на соответствие полный путь. Use the <rootDir> string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Пример: [«<rootDir>/build/», «<rootDir>/node_modules/»].

testRegex [string]

Default: (/__tests__/.*|(\\.|/)(test|spec))\\.jsx?$

The pattern Jest uses to detect test files. By default it looks for .js and .jsx files inside of __tests__ folders, as well as any files with a suffix of .test or .spec (e.g. Component.test.js or Component.spec.js). It will also find files called test.js or spec.js. See also testMatch [array<string>], but note that you cannot specify both options.

The following is a visualization of the default regex:

├── __tests__
│   └── component.spec.js # test
│   └── anything # test
├── package.json # not test
├── foo.test.js # test
├── bar.spec.jsx # test
└── component.js # not test

Note: testRegex will try to detect test files using the absolute file path, therefore, having a folder with a name that matches it will run all the files as tests

testResultsProcessor [string]

Значение по умолчанию: undefined

This option allows the use of a custom results processor. This processor must be a node module that exports a function expecting an object with the following structure as the first argument and return it:

{
  "success": boolean,
  "startTime": epoch,
  "numTotalTestSuites": number,
  "numPassedTestSuites": number,
  "numFailedTestSuites": number,
  "numRuntimeErrorTestSuites": number,
  "numTotalTests": number,
  "numPassedTests": number,
  "numFailedTests": number,
  "numPendingTests": number,
  "openHandles": Array<Error>,
  "testResults": [{
    "numFailingTests": number,
    "numPassingTests": number,
    "numPendingTests": number,
    "testResults": [{
      "title": string (message in it block),
      "status": "failed" | "pending" | "passed",
      "ancestorTitles": [string (message in describe blocks)],
      "failureMessages": [string],
      "numPassingAsserts": number,
      "location": {
        "column": number,
        "line": number
      }
    },
    ...
    ],
    "perfStats": {
      "start": epoch,
      "end": epoch
    },
    "testFilePath": absolute path to test file,
    "coverage": {}
  },
  ...
  ]
}

testRunner [string]

Default: jasmine2

This option allows the use of a custom test runner. The default is jasmine2. A custom test runner can be provided by specifying a path to a test runner implementation.

The test runner module must export a function with the following signature:

function testRunner(
  globalConfig: GlobalConfig,
  config: ProjectConfig,
  environment: Environment,
  runtime: Runtime,
  testPath: string,
): Promise<TestResult>;

An example of such function can be found in our default jasmine2 test runner package.

testURL [string]

Default: http://localhost

This option sets the URL for the jsdom environment. It is reflected in properties such as location.href.

timers [string]

Значение по умолчанию: real

Setting this value to fake allows the use of fake timers for functions such as setTimeout. Fake timers are useful when a piece of code sets a long timeout that we don't want to wait for in a test.

transform [object<string, pathToTransformer | [pathToTransformer, object]>]

Default: {"^.+\\.[jt]sx?$": "babel-jest"}

A map from regular expressions to paths to transformers. A transformer is a module that provides a synchronous function for transforming source files. For example, if you wanted to be able to use a new language feature in your modules or tests that aren't yet supported by node, you might plug in one of many compilers that compile a future version of JavaScript to a current one. Example: see the examples/typescript example or the webpack tutorial.

Examples of such compilers include:

Note: a transformer is only run once per file unless the file has changed. During the development of a transformer it can be useful to run Jest with --no-cache to frequently delete Jest's cache.

Note: when adding additional code transformers, this will overwrite the default config and babel-jest is no longer automatically loaded. If you want to use it to compile JavaScript or Typescript, it has to be explicitly defined by adding {"\\.[jt]sx?$": "babel-jest"} to the transform property. See babel-jest plugin

transformIgnorePatterns [массив<string>]

Значение по умолчанию: ["/node_modules/"]

An array of regexp pattern strings that are matched against all source file paths before transformation. If the test path matches any of the patterns, it will not be transformed.

Эти строки шаблонов проверяют на соответствие полный путь. Use the <rootDir> string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories.

Example: ["<rootDir>/bower_components/", "<rootDir>/node_modules/"].

Sometimes it happens (especially in React Native or TypeScript projects) that 3rd party modules are published as untranspiled. Since all files inside node_modules are not transformed by default, Jest will not understand the code in these modules, resulting in syntax errors. To overcome this, you may use transformIgnorePatterns to allow transpiling such modules. You'll find a good example of this use case in React Native Guide.

unmockedModulePathPatterns [массив<string>]

Значение по умолчанию: []

An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them. If a module's path matches any of the patterns in this list, it will not be automatically mocked by the module loader.

This is useful for some commonly used 'utility' modules that are almost always used as implementation details almost all the time (like underscore/lo-dash, etc). It's generally a best practice to keep this list as small as possible and always use explicit jest.mock()/jest.unmock() calls in individual tests. Explicit per-test setup is far easier for other readers of the test to reason about the environment the test will run in.

It is possible to override this setting in individual tests by explicitly calling jest.mock() at the top of the test file.

verbose [boolean]

Значение по умолчанию: false

Indicates whether each individual test should be reported during the run. All errors will also still be shown on the bottom after execution. Note that if there is only one test file being run it will default to true.

watchPathIgnorePatterns [массив<string>]

Значение по умолчанию: []

An array of RegExp patterns that are matched against all source file paths before re-running tests in watch mode. If the file path matches any of the patterns, when it is updated, it will not trigger a re-run of tests.

These patterns match against the full path. Use the <rootDir> string token to include the path to your project's root directory to prevent it from accidentally ignoring all of your files in different environments that may have different root directories. Example: ["<rootDir>/node_modules/"].

Even if nothing is specified here, the watcher will ignore changes to any hidden files and directories, i.e. files and folders that begin with a dot (.).

watchPlugins [массив<string | [string, object]>]

Значение по умолчанию: []

This option allows you to use custom watch plugins. Read more about watch plugins here.

Examples of watch plugins include:

watchman [boolean]

Default: true

Whether to use watchman for file crawling.

← The Jest ObjectJest CLI Options →