[bug] duplicate manual mock found in separate directories

[paularmstrong]

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

What is the current behavior?

Given a file tree:

src/app/modules
├── module1
│   ├── index.js
│   ├── __tests__/
├── module2
│   ├── index.js
│   ├── __tests__/

I use the modules outside of the modules directory by importing them by directory name:

import Module1 from '../modules/module1';
import Module2 from '../modules/module2';

I'd like to be able to mock module1 and module2. However, if I create src/app/modules/module1/__mocks__/index.js and src/app/modules/module2/__mocks__/index.js, I'm given the duplicate manual mock found error from jest-haste-map.

If, however, I try to create src/app/modules/__mocks__/{module1.js,module2.js}, the mocked files are not used.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal repository on GitHub that we can npm install and npm test.

See above behavior.

What is the expected behavior?

I would expect either approach to work, given that the first case uses different paths and the second case uses the pathname of the module.

Run Jest again with --debug and provide the full configuration it prints. Please mention your node and npm version and operating system.

node v6.2.0
npm v3.8.9
OS X 10.11.6

> NODE_ENV=test jest --env jsdom "--debug" "src/app/redux/modules/devices"

jest version = 17.0.0
test framework = jasmine2
config = {
  "moduleFileExtensions": [
    "js",
    "json"
  ],
  "moduleDirectories": [
    "node_modules"
  ],
  "moduleNameMapper": [
    [
      "^.+\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$",
      "/Users/paul/dev/tools/jest/mock-assets.js"
    ],
    [
      "^.+\\.css$",
      "identity-obj-proxy"
    ]
  ],
  "name": "dev",
  "setupTestFrameworkScriptFile": "/Users/paul/dev/tools/jest/setup-framework.js",
  "testPathDirs": [
    "/Users/paul/dev/src"
  ],
  "testRegex": "/__tests__/.*\\.test\\.js$",
  "timers": "fake",
  "rootDir": "/Users/paul/dev",
  "setupFiles": [],
  "testRunner": "/Users/paul/dev/node_modules/jest-jasmine2/build/index.js",
  "testEnvironment": "/Users/paul/dev/node_modules/jest-environment-jsdom/build/index.js",
  "transform": [
    [
      "^.+\\.jsx?$",
      "/Users/paul/dev/node_modules/babel-jest/build/index.js"
    ]
  ],
  "usesBabelJest": true,
  "automock": false,
  "bail": false,
  "browser": false,
  "cacheDirectory": "/var/folders/dm/vt920lmd6tzdq_709zkykwx40000gn/T/jest",
  "coveragePathIgnorePatterns": [
    "/node_modules/"
  ],
  "coverageReporters": [
    "json",
    "text",
    "lcov",
    "clover"
  ],
  "expand": false,
  "globals": {},
  "haste": {
    "providesModuleNodeModules": []
  },
  "mocksPattern": "__mocks__",
  "modulePathIgnorePatterns": [],
  "noStackTrace": false,
  "notify": false,
  "preset": null,
  "resetMocks": false,
  "resetModules": false,
  "snapshotSerializers": [],
  "testPathIgnorePatterns": [
    "/node_modules/"
  ],
  "testURL": "about:blank",
  "transformIgnorePatterns": [
    "/node_modules/"
  ],
  "useStderr": false,
  "verbose": null,
  "watch": false,
  "cache": true,
  "watchman": true,
  "testcheckOptions": {
    "times": 100,
    "maxSize": 200
  }
}
jest-haste-map: duplicate manual mock found:
  Module name: index
  Duplicate Mock path: /Users/paul/dev/src/app/modules/push-notification-manager/__mocks__/index.js
This warning is caused by two manual mock files with the same file name.
Jest will use the mock file found in:
/Users/paul/dev/src/app/modules/push-notification-manager/__mocks__/index.js
 Please delete one of the following two files:
 /Users/paul/dev/src/app/modules/image-file/__mocks__/index.js
/Users/paul/dev/src/app/modules/push-notification-manager/__mocks__/index.js


No tests found
  1 file checked.
  testPathDirs: /Users/paul/dev/src - 1 match
  testRegex: /__tests__/.*\.test\.js$ - 0 matches
  testPathIgnorePatterns: /node_modules/ - 1 match

[yongdamsh]

+1

[yongdamsh]

In my case, after clear the cacheDirectory/var/folders/dm/vt920lmd6tzdq_709zkykwx40000gn/T/jest and re-install npm dependencies, these messages have been disappeared.

[LegNeato]

Here's the offending code:

https://github.com/facebook/jest/blob/cd8976ec50dbed79cfe07f275052cdd80d466e73/packages/jest-haste-map/src/index.js#L98

But it looks like the behavior might be explicitly wanted as there is a test confirming it:

https://github.com/facebook/jest/blob/8de90b320c87a0a36d68f6bd8177620a985df269/packages/jest-haste-map/src/__tests__/__snapshots__/index-test.js.snap#L15

Which was added in:

cfade28

I wonder why we are using basename rather than the whole path as the key?

/cc @flarnie

[LegNeato]

This means that basenames for modules need to be globally unique in a project when using manual mocks. For my use case, it means I can't do something like:

import { MyWhatever } from 'models/MyWhatever/schema';
import { MyOtherWhatever } from 'models/MyOtherWhatever/schema';

and use manual mocks at the same time. Jest will currently see them both as mocking schema and complain.

Though the workaround is trivial (s/schema/MyWhateverSchema/), it feels like a bug to rename and restructure non-test code to make jest happy 🐞 .

[cpojer]

Yes this does suck indeed. The manual mocking system is really not good and I'm happy to accept PRs that will improve the situation, assuming we can make sure we don't break all of FB (but I can take care of that :) )

[LegNeato]

Cool. I might find some time tomorrow to cook up a patch, but no promises though 😅

[juliankrispel]

@cpojer is there a particular reason for this behaviour?

Could it have anything to do with the fact that fb uses unique filenames for modules? I don't see otherwise how not allowing two mocks with the same name makes any sense...

[cpojer]

Yes, mocks are "global" as well. This is a terrible design that we have to live with, unfortunately. At FB we have 4000+ mock files in the wrong location (and often there isn't even a proper location). It is likely we will fix this early next half, so this should improve in Jest. I'm happy to support PRs that improve the behavior in Jest for open source – if we can retain the old behavior for Jest at FB for now.

[juliankrispel]

@cpojer how about a flag? Would you accept a pr that enables/disables this with a flag?

[cpojer]

Yeah, it should be a config option. But I'm not just talking about the warning, I'm also talking about the feature in general.

[juliankrispel]

@cpojer right - which parts of jest does this touch?

[cpojer]

The resolution code is called from jest-runtime: https://github.com/facebook/jest/blob/master/packages/jest-runtime/src/index.js and is somewhere in jest-resolve and jest-resolve-dependencies.

[juliankrispel]

@cpojer thanks for the pointers 👍

[ColCh]

@cpojer what about some global override, like JEST_USE_BASENAME_FOR_CACHING, to switch this behaviour?

At least, we can enjoy non-unique filenames, and it will not break anything in FB.

Of course, it's a temporary solution.

I mean, this is in some /etc/profile or ~/.bashrc

export JEST_USE_BASENAME_FOR_CACHING="true"

(or some file with env)
and then

$ jest

or this one, without env file modifications:

$ JEST_USE_BASENAME_FOR_CACHING="true" jest

What you think? It's a sort of hack or it's ok? 😉

[EnoahNetzach]

I just tried with a new repo, using two versions of jest (^15.0.0 and ^17.0.0) and, although the latter gives the warning, the test behaves as expected.

@ColCh I don't think the issue here is with the cache, probably a more suitable name could be JEST_USE_BASENAME_FOR_MOCKING.