Fix diff command when running in nested directory

[vkammerer]

I noticed that my tests were:

• failing when running in parallel (with melos)
• but passing when running independently or sequentially.

This is due to the diffing command being applied to the whole directory, and not just to the current workingDir. So if I have package a and package b, a diff in package b (due to a file being regenerated) will cause package a to notice a diff and fail the test, even if its own directory doesn't have any diff.

This PR makes sure that the diff is computed only for the current working directory, which enables tests using this package to run in parallel inside monorepos.

[kevmoo]

That's what I have https://pub.dev/documentation/build_verify/latest/build_verify/expectBuildClean.html for

...although this might be better.

Would you update the tests to validate this behavior?

[vkammerer]

@kevmoo I reworked my PR by:

• first updating the tests with 24b5b5d. If you checkout the branch at this commit, the test when package b has modifications, package a test should pass and package b test should fail will fail
• then added my original fix on top, which makes the test pass

[vkammerer]

Hi @kevmoo , is there anything else I should do to move this PR forward?

[kevmoo]

@vkammerer – looking now! Thanks for your patience!

[kevmoo]

Thanks again, @vkammerer – published!

[vincent-hoodoo]

@kevmoo yay! My CI tests duration will be happy to hear the news 😃