Issues with coverage and rewire

🐛 Bug Report

Hi, I have a public repo that doesn’t produce coverage for file scraper.test.js. File is found in tests directory. I do have another test file that doesn’t have any issue.

However, the problematic file is using rewire npm module, and I have seen some issues with it lately. I did try to completely remove it, but the problem still persists.

To Reproduce

In folder crawler Run: jest --coverage --bail --findRelatedTests ./__tests__/scraper.test.js or: jest --coverage

Expected behavior

I expect to see coverage report for scraper.js. Tests run successfully but I there is no coverage data.

Link to repl or repo

Repo - develop branch

envinfo

System: OS: Linux 5.2 Fedora 30 (Workstation Edition) 30 (Workstation Edition) CPU: (4) x64 Intel® Core™ i7-7500U CPU @ 2.70GHz Binaries: Node: 12.8.1 - /usr/bin/node npm: 6.11.2 - ~/.npm-packages/bin/npm npmPackages: jest: ^24.9.0 => 24.9.0

[SimenB]

I doubt we’ll add support for rewire (jest has builtin support for mocking modules via jest.mock and jest.doMock), but if anybody wanna send a PR that’s of course welcome

[JNBourrat]

@An-dz Thanks, I’ll be sure to take a look at it.

For my end I ended up using babel-plugin-rewire instead of rewire itself. I was able to use __get__ and __set__ to mock the tested module’s private functions and not rewire the whole module.