Coverage empty when calling test script via yarn

[pdfowler]

Repro Repo

Sorry - Private repo. Trying to gen min repro case

Configuration:

In my package.json file, I have the following lines in my scripts node:

scripts: { ...
    "test": "cross-env NODE_ENV=test env-path -p test/.env mocha \"test/**/*.test.js\" --recursive --exit",
    "test:coverage": "cross-env NODE_ENV=test nyc --reporter=lcov yarn run test",
... },

Expected Behavior

Running yarn run test:coverage should populate the lcov report at ./coverage/lcov-report/index.html

Observed Behavior

The lcov report is completely empty

Troubleshooting steps

When my test:coverage script is changed to have the contents of the test script directly in the test:coverage script, my lcov report is correctly generated

"test:coverage": "cross-env NODE_ENV=test ESM_DISABLE_CACHE=1 nyc --cache=false --reporter=lcov env-path -p test/.env mocha \"test/**/*.test.js\" --recursive --exit",

Environment Information

  System:
    OS: macOS Mojave 10.14.6
    CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
    Memory: 402.93 MB / 16.00 GB
  Binaries:
    Node: 10.16.3 - ~/.nvm/versions/node/v10.16.3/bin/node
    Yarn: 1.19.1 - ~/.yarn/bin/yarn
    npm: 5.1.0 - /usr/local/bin/npm
  npmPackages:
    @babel/core: ^7.0.0 => 7.1.6 
    @babel/plugin-proposal-class-properties: ^7.0.0 => 7.1.0 
    @babel/plugin-proposal-decorators: ^7.2.0 => 7.2.0 
    @babel/plugin-proposal-do-expressions: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-export-default-from: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-export-namespace-from: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-function-bind: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-function-sent: ^7.0.0 => 7.1.0 
    @babel/plugin-proposal-json-strings: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-logical-assignment-operators: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-nullish-coalescing-operator: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-numeric-separator: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-optional-chaining: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-pipeline-operator: ^7.0.0 => 7.0.0 
    @babel/plugin-proposal-throw-expressions: ^7.0.0 => 7.0.0 
    @babel/plugin-syntax-dynamic-import: ^7.0.0 => 7.0.0 
    @babel/plugin-syntax-import-meta: ^7.0.0 => 7.0.0 
    @babel/plugin-transform-runtime: ^7.1.0 => 7.1.0 
    @babel/polyfill: ^7.0.0 => 7.0.0 
    @babel/preset-env: ^7.2.0 => 7.2.0 
    @babel/preset-react: ^7.0.0 => 7.0.0 
    @babel/register: ^7.0.0 => 7.0.0 
    @babel/runtime: ^7.1.5 => 7.1.5 
    @types/babel-core: ^6.25.0 => 6.25.3 
    @types/babel__core: ^7.0.4 => 7.0.4 
    babel-eslint: ^10.0.1 => 10.0.1 
    babel-loader: ^8.0.0 => 8.0.4 
    babel-plugin-istanbul: ^5.1.0 => 5.1.0 
    babel-plugin-root-import: ^6.1.0 => 6.1.0 
    babel-plugin-system-import-transformer: ^3.1.0 => 3.1.0 
    eslint-import-resolver-babel-plugin-root-import: ^1.1.1 => 1.1.1 
    eslint-plugin-babel: ^5.3.0 => 5.3.0 
    nyc: ^14.1.1 => 14.1.1 

Other Notes:

Since last running my coverage script (I know, I know):

• I recently upgraded from yarn@~1.09 (?) to yarn@1.19
• I upgraded node from 8.x to 10.x
• Observed originally with nyc@13.1.0. Updated to nyc@14 to no effect.

[coreyfarrell]

Please test with the beta release of nyc 15. nyc 15 makes use of a new technique for wrapping child processes which fixes known issues with yarn. Be sure to upgrade babel-plugin-istanbul to the beta release of 6 at the same time.

[pdfowler]

That did the trick!

yarn add nyc@next babel-plugin-istanbul@next`;
yarn run test

Result: Successfully generated coverage report, followed by recalling how far we still have to go on coverage. At least we've got most of our critical logic covered!

[coreyfarrell]

Thanks for reporting back, I'm going to close this as no further code changes are expected. You can click Subscribe on #1104 to get updates about the progress for the final release of nyc@15.