Mocked module return undefined

[armandabric]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
This do not works:

jest.mock('./doBar', () => {
    return jest.fn().mockReturnValue(42);
});

When using doBar() in another component it return undefined.

You could find a full example here: https://gist.github.com/Spy-Seth/abd9e98110d9ddc437fe99df0e86ff0b

This break with jest v17.0.3 but was working with jest v16.0.1

What is the expected behavior?
doBar() should return 42.

Environment:

jest version = 17.0.3
test framework = jasmine2
config = {
  "cacheDirectory": "/app/var/jest",
  "moduleFileExtensions": [
    "js",
    "jsx"
  ],
  "testPathDirs": [
    "/app/src",
    "/app/tests/units",
    "/app/tests/functionals"
  ],
  "testRegex": "((.*)\\.(test|spec)\\.(js|jsx)$)|((.*)Test\\.(js|jsx)$)",
  "resetMocks": true,
  "rootDir": "/app",
  "name": "-app",
  "setupFiles": [
    "/app/node_modules/babel-polyfill/lib/index.js"
  ],
  "testRunner": "/app/node_modules/jest-jasmine2/build/index.js",
  "transform": [
    [
      "^.+\\.jsx?$",
      "/app/node_modules/babel-jest/build/index.js"
    ]
  ],
  "usesBabelJest": true,
  "automock": false,
  "bail": false,
  "browser": false,
  "coveragePathIgnorePatterns": [
    "/node_modules/"
  ],
  "coverageReporters": [
    "json",
    "text",
    "lcov",
    "clover"
  ],
  "expand": false,
  "globals": {},
  "haste": {
    "providesModuleNodeModules": []
  },
  "mocksPattern": "__mocks__",
  "moduleDirectories": [
    "node_modules"
  ],
  "moduleNameMapper": {},
  "modulePathIgnorePatterns": [],
  "noStackTrace": false,
  "notify": false,
  "preset": null,
  "resetModules": false,
  "snapshotSerializers": [],
  "testEnvironment": "jest-environment-jsdom",
  "testPathIgnorePatterns": [
    "/node_modules/"
  ],
  "testURL": "about:blank",
  "timers": "real",
  "transformIgnorePatterns": [
    "/node_modules/"
  ],
  "useStderr": false,
  "verbose": null,
  "watch": false,
  "cache": true,
  "watchman": true
}

Node: v6.9.0

[cpojer]

Can you double check if this works with 17.0.0 or not?

[armandabric]

Same result with jest 17.0.0 😢

[acateland]

same result here even the code examples

jest.mock('../moduleName', () => {
  return jest.fn(() => 42);
});

const moduleName = require('../moduleName'); // This runs the function specified as second argument to `jest.mock`.
moduleName(); // Will return '42';

doesn't work anymore, my test using this technique in 16.0.2 worked fine.

[shouze]

Ping @cpojer

[shouze]

ping @Spy-Seth is it fixed by v18.0.0?

[thymikee]

@Spy-Seth I've tested the case from attached gist on v17 and v18, test pass.
@acateland your example is valid too.

Closing this, but happy to reopen if you can provide a repo with failing test (can be something with configuration).

[armandabric]

Adding the "resetMocks": true configuration allow me reproduce the buggy behavior in my application.

[thymikee]

Yeah, so resetMocks and jest.resetAllMocks() works this way now, that it wipes all mocks data. Here's a relevant issue to bring back jest.clearAllMocks() back to Jest: #2134.

[coleturner]

Hey, just wanted to add super late but I'm also running into this issue. Both require and jest.requireActual return undefined and cannot seem to diagnose it from require.cache either. I wish I had a repo to share but I also tried resetting all the mocks too. The only way to see the modules (react, prop-types) is to use jest.unmock(...)

• Jest v24 via Gulp
• Disabling hoisting does not seem to have any effect

[DarinDev1000]

jest.requireActual sometimes returns undefined. Any idea why?

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