--findRelatedTests path case sensitivity on Windows

[mbelsky]

🐛 Bug Report

Running jest --findRelatedTests <filepath> with upper-cased part of path does not find any test.

To Reproduce

Steps to reproduce the behavior:

1. git clone https://github.com/mbelsky/js-problems.git
2. cd js-problems
3. npm i
4. npx jest --findRelatedTests ./PROBLEMS/001-SUM.JS

Result:

No tests found, exiting with code 1
Run with `--passWithNoTests` to exit with code 0
No files found in C:\Users\publi\js\js-problems.
Make sure Jest's configuration does not exclude this directory.
To set up Jest, make sure a package.json file exists.
Jest Documentation: facebook.github.io/jest/docs/configuration.html
Pattern: .\\PROBLEMS\\001-SUM.JS - 0 matches

Expected behavior

 FAIL  problems/__tests__/001.js
  × Тестирование задачи "001-sum" (5ms)

  ● Тестирование задачи "001-sum"

    expect(received).toBe(expected) // Object.is equality

    Expected: 1
    Received: undefined

      2 | 
      3 | test('Тестирование задачи "001-sum"', () => {
    > 4 |     expect(sum(-100)).toBe(1);
        |                       ^
      5 |     expect(sum(0)).toBe(1);
      6 |     expect(sum(1)).toBe(1);
      7 |     expect(sum(2)).toBe(3);

      at Object.toBe (problems/__tests__/001.js:4:23)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        1.228s, estimated 2s
Ran all test suites related to files matching /.\\PROBLEMS\\001-SUM.JS/i.

envinfo

  System:
    OS: Windows 10
    CPU: (4) x64 Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
  Binaries:
    Node: 10.16.0 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.16.0 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 6.9.0 - C:\Program Files\nodejs\npm.CMD

[mbelsky]

I may try to fix that issue. Could someone give me an idea from where to start, please?

[SimenB]

The OP should include a reproduction, btw.

---

Awesome you can work on this! As for where to start, I'd start by just sticking in breakpoints SearchSource: https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/packages/jest-core/src/SearchSource.ts#L280-L311

My guess is that tests are missing there, so just walk up the callstack until you find where we compare against files found on the FS. The issue is probably somewhere in https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/packages/jest-resolve-dependencies/src/index.ts#L73-L136

[SimenB]

We have a few integration tests that we skip on windows that might cover this (I haven't checked). You might be able to activate them?

https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/e2e/__tests__/jestChangedFiles.test.ts#L16
https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/e2e/__tests__/cliHandlesExactFilenames.test.ts#L16
https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/e2e/__tests__/dependencyClash.test.ts#L14

[mbelsky]

To debug the issue I've added this config in .vscode/launch.json and set a breakpoint in packages/jest-core/src/SearchSource.ts line 268.

    {
      "type": "node",
      "request": "launch",
      "name": "Debug Jest --findRelatedTests",
      "program": "${workspaceFolder}/packages/jest-cli/bin/jest.js",
      "args": [
        "--runInBand",
        "--findRelatedTests",
        "packages/jest-core/src/FailedTestsCache.ts"
      ]
    }

https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/packages/jest-core/src/SearchSource.ts#L268
And on the line I see that globalConfig.findRelatedTests and paths are undefined.

Does it mean that I use wrong launch config to debug that or globalConfig.findRelatedTests doesn't correlate with --findRelatedTests argument?

[SimenB]

You're probably debugging the test and not jest itself when it executes the test. You need to put a breakpoint in the compiled code, so in packages/jest-core/build/SearchSource.js

[mbelsky]

The first issue that I face is HasteFs.exists is case-sensitive. It doesn't make real check with filesystem and just look for a key in Map. So dependencies resolving ends here for upper-cased path.
https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/packages/jest-resolve-dependencies/src/index.ts#L118

I've passed this conclusion with some hacks and found one more checking in collectModules like previous.
https://github.com/facebook/jest/blob/554573036ae7529425aa157a1fd757612289abb5/packages/jest-resolve-dependencies/src/index.ts#L94

This time it's Set instead of Map and it's same issue.

I'm not sure what a solution will be more elegant to handle case insensitivity here. Do you have any suggestions?

--
btw a repro has been added.

[SimenB]

Is there some check we can make for "is the FS case sensitive"? If we can, we could just normalize file paths in the Maps and Sets when the FS is case insensitive using toLowerCase() or something. I guess we could check if os.platform() === 'win32', but that seems somewhat fragile.

---

And issue with fixing this btw is that you might end up with scripts that work on windows but not on mac/linux (e.g. jest integrationTests), while currently all OSes behaves the same, which might be considered a feature.