#5067 Add forceCoverageRegex configuration option

[efegurkan]

Summary

As explained in #5067 if you have tests in source files there is no way to collect coverage from those files since jest returns false for should instrument checks.

This PR adds forceCoverageRegex config option to allow collecting coverage even
if the file is ignored. This way you can collect coverage from the
source files with tests or specific files you ignored manually.

Test plan
Create a file which includes the tests with source files 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);
  });
}

Add 'forceCoverageRegex' field to the jest options same as testRegex. Run jest with collectCoverage option.

In this PR I add unit tests for jest-runtime/src/should_instrument.js also.

[SimenB]

This is failing on Appveyor.

Could you also update the changelog?

[SimenB]

Should it include pattern in the name to indicate it's a regexp?

[SimenB]

Seems like it's called forceCoverageRegex elsewhere, can you make sure it's consistent?

[efegurkan]

I actually wrote it wrong on the docs :) it is forceCoverageRegex. Just updated the PR

[codecov-io]

Codecov Report

Merging #5081 into master will increase coverage by 0.11%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #5081      +/-   ##
==========================================
+ Coverage   60.65%   60.76%   +0.11%     
==========================================
  Files         199      199              
  Lines        6643     6645       +2     
  Branches        4        4              
==========================================
+ Hits         4029     4038       +9     
+ Misses       2614     2607       -7

Impacted Files	Coverage Δ
packages/jest-config/src/normalize.js	91.95% <ø> (ø)	⬆️
packages/jest-config/src/defaults.js	100% <ø> (ø)	⬆️
packages/jest-config/src/valid_config.js	100% <ø> (ø)	⬆️
packages/jest-config/src/index.js	23.8% <ø> (ø)	⬆️
packages/jest-runtime/src/should_instrument.js	100% <100%> (+41.17%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cfb7ee1...3681ee9. Read the comment docs.

[SimenB]

I see no reason to not support this. Thanks for the PR!

[cpojer]

I have a few concerns about the naming here. Jest's options normally use "Pattern" rather than "Regex", even if they are regex. Most users only use testMatch which is based on globs. Should we change this option to forceCoverageMatch and use globs instead?

[cpojer]

Can you rewrite this? What about "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."

[efegurkan]

Sure thing. 👍

[cpojer]

One more thought: if this is primarily to enable coverage for test files, should we instead make this a boolean flag "includeTestsInCoverage" instead of having people fumble with regex/globs?

[efegurkan]

@cpojer for the "includeTestsInCoverage" concerns of yours, I have some cases which we have regular tests like __tests__/something.spec.js and source files with tests like packages/src/sourcefile.t.js. You probably don't want to add all of your tests to the coverage.

It is probably a better idea to use globs though I agree, I will update the PR accordingly

[efegurkan]

Hey I updated the PR and changed regex to Glob.

[cpojer]

Thanks for the PR and for making changes to it :)

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.