Jest coverage targets the wrong file

[dispix]

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

Bug

What is the current behavior?

Considering this file tree:

app/services/
├── categories
│   ├── Parser.js
│   ├── __mocks__
│   │   └── Parser.js
│   ├── actions.js
│   ├── constants.js
│   ├── reducer
│   │   ├── data.js
│   │   ├── index.js
│   │   ├── list.js
│   │   └── tests
│   │       ├── data.test.js
│   │       └── list.test.js
│   ├── sagas.js
│   ├── selectors.js
│   └── tests
│       ├── Parser.test.js
│       ├── actions.test.js
│       └── selectors.test.js
├── index.js
├── items
│   ├── Parser.js
│   ├── __mocks__
│   │   └── Parser.js
│   ├── actions.js
│   ├── constants.js
│   ├── reducer
│   │   ├── data.js
│   │   ├── delete.js
│   │   ├── fetch.js
│   │   ├── index.js
│   │   ├── list.js
│   │   ├── next.js
│   │   ├── tests
│   │   │   ├── data.test.js
│   │   │   ├── delete.test.js
│   │   │   ├── fetch.test.js
│   │   │   ├── list.test.js
│   │   │   ├── next.test.js
│   │   │   └── update.test.js
│   │   └── update.js
│   ├── sagas.js
│   ├── selectors.js
│   └── tests
│       ├── Parser.test.js
│       ├── actions.test.js
│       └── selectors.test.js
└── router
    ├── reducer.js
    ├── selectors.js
    └── tests
        ├── reducer.test.js
        └── selectors.test.js

And my coverage when I run the npm run jest -- --coverage app/services/items/reducer/tests/list.test.js command:

---------------------------------|----------|----------|----------|----------|----------------|
File                             |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
---------------------------------|----------|----------|----------|----------|----------------|
All files                        |     5.98 |     8.41 |    10.75 |     9.14 |                |
 services/categories             |        0 |        0 |        0 |        0 |                |
  Parser.js                      |        0 |        0 |        0 |        0 |1,3,22,27,28,30 |
  actions.js                     |        0 |      100 |        0 |        0 |... 20,27,34,38 |
  constants.js                   |        0 |      100 |      100 |        0 |         1,7,13 |
  selectors.js                   |        0 |      100 |        0 |        0 |1,7,12,20,23,25 |
 services/categories/reducer     |    33.33 |    45.83 |    33.33 |    42.11 |                |
  data.js                        |        0 |        0 |        0 |        0 |... 26,30,32,34 |
  list.js                        |      100 |      100 |      100 |      100 |                |
 services/items/reducer          |       70 |    80.82 |     87.5 |    73.21 |                |
  data.js                        |      100 |      100 |      100 |      100 |                |
  delete.js                      |      100 |      100 |      100 |      100 |                |
  fetch.js                       |      100 |      100 |      100 |      100 |                |
  list.js                        |        0 |        0 |        0 |        0 |... 40,42,44,46 |
  next.js                        |      100 |      100 |      100 |      100 |                |
  update.js                      |      100 |      100 |      100 |      100 |                |
 services/router                 |        0 |        0 |        0 |        0 |                |
  reducer.js                     |        0 |        0 |        0 |        0 |... 32,39,41,43 |
  selectors.js                   |        0 |      100 |        0 |        0 |1,7,12,20,23,25 |
---------------------------------|----------|----------|----------|----------|----------------|

(I removed some unrelated part of the coverage and file tree).

Jest coverage targets the services/categories/reducer/list file when running the tests on services/items/reducer/list. I import the right file and it is actually testing the right file, meaning that voluntarily changing something in services/items/reducer/list makes the tests fail.

If the current behavior is a bug, please provide the steps to reproduce and either a repl.it demo through https://repl.it/languages/jest or a minimal repository on GitHub that we can yarn install and yarn test.

This comes from a private repository and I don't think I can give you a runnable example 😞

What is the expected behavior?

The coverage should target the right file.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

OS: MacOS Sierra 10.12.5 (16F73)
Node: v7.10.0
Yarn: v0.24.6
Jest: v20.0.4
Jest configuration:

"jest": {
    "collectCoverageFrom": [
      "app/components/**/*.{js,jsx}",
      "app/services/**/*.{js,jsx}",
      "app/utils/**/*.{js,jsx}",
      "app/containers/**/reducer.js",
      "app/containers/**/selectors.js",
      "app/containers/**/actions.js",
      "app/containers/**/constants.js",
      "!app/**/*.test.{js,jsx}",
      "!app/*/RbGenerated*/*.{js,jsx}",
      "!app/app.js",
      "!app/routes.js",
      "!app/themes.js",
      "!app/global-styles.js",
      "!app/**/sagas.js",
      "!app/services/form/intlForm.js",
      "!app/services/**/index.js"
    ],
    "coverageThreshold": {
      "global": {
        "statements": 98,
        "branches": 91,
        "functions": 98,
        "lines": 98
      }
    },
    "moduleDirectories": [
      "node_modules",
      "app"
    ],
    "moduleNameMapper": {
      ".*\\.(css|less|styl|scss|sass)$": "<rootDir>/internals/mocks/cssModule.js",
      ".*\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/internals/mocks/image.js"
    },
    "setupTestFrameworkScriptFile": "<rootDir>/internals/testing/test-bundler.js",
    "testRegex": "tests/.*\\.test\\.js$"
  },

[dispix]

Additional informations:

• If I add a simple console.log in my app/services/items/reducer/list files, the coverage now targets it as expected. I initially added one to make sure the right file was loaded and it not only showed up but also corrected the coverage.
• Running the same command with --no-cache corrects the issue too.

[stipsan]

Hey @dispix,

Can you test if this fix resolves your case? #4432

[dispix]

Hi @stipsan !

I was about to test it but got an error when trying to target the master branch from this repository:

devDependencies: {
  "jest-cli": "facebook/jest#master"
}

error /.../node_modules/jest-cli: Command failed.
Exit code: 1
Command: sh
Arguments: -c yarn run build --silent
Directory: /.../node_modules/jest-cli
Output:
module.js:487
    throw err;
    ^

Error: Cannot find module 'string-length'
    at Function.Module._resolveFilename (module.js:485:15)
    at Function.Module._load (module.js:437:25)
    at Module.require (module.js:513:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/.../node_modules/jest-cli/scripts/build.js:32:22)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.

Am I missing something with the way I should target a git repository as a dependency ?

[SimenB]

I think you have to clone and build the repo locally. When referencing the git repo you don't get the dev deps necessary for building

[stipsan]

Like @SimenB says the easiest way to test it is to:

1. Create your local clone.
2. Run yarn install in the clone (using yarn v0.27.5 or later as jest is using the workspaces feature).
3. npm link to compile jest so you get the same files available as when you yarn add jest-cli right off npm.
4. cd to your project and npm link jest-cli, this should setup a symlink for you to jest.

[dispix]

Just tried following the steps to link a local version of jest (npm link was throwing errors left and right) and this doesn't seem to fix the issue 😞

Using yarn@0.27.5 and the master branch of this repository.

[SimenB]

No need to link, just clone, run yarn and then in your other project, do ../jest/jest

[dispix]

Doesn't change a thing though, both methods still display the wrong coverage.

[stipsan]

Very strange. It might still be loading the old packages for babel-jest and jest-runtime since you get the same results.
Any chance you can create a repo that reproduces the problem? It'll help me check for sure if #4432 will fix it, if it doesn't I'll be able to work on a fix using your test case. :)

[jackjocross]

After upgrading to jest-runtime@21.2.1 and babel-jest@21.2.0 I am no longer experiencing this issue.

[robertmain]

I'm having a similar issue with Jest generating random or nonsensical coverage data in #4960

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