playwright: add support for test file prefixes in JSON reports

[ono-max]

@Konboi suggested me the following approach yesterday, this is definitely a valid approach. In this PR, I explored the another approach, which is automatically detecting test paths.

# trim 'test' dirctory from the subset inputs and set it again

$ find test -name "*.spec.ts" \
  | sed 's|^test/||' \ 
  | launchable subset --target 30% playwright \
  > subset.txt

$ sed 's|^|test/|' subset.txt > test-list.txt
$ npx playwright test $(cat test-list.txt)

The basic idea is computing the relative directory by comparing the configFile against rootDir as follows:

 Example:
            configFile = /repo/playwright.config.ts
            rootDir    = /repo/tests
            relpath(...) -> "tests"

[ono-max]

@Konboi

No rush at all, but can you please review this PR?

What do you think about this approach? Do you foresee potential risks regarding my change?

[Konboi]

I think the approach makes sense, but "test_prefix" might not be the best name.
We might be able to come up with something clearer.

[ono-max]

Thanks for your suggestion. I renamed some method names 👍

[Konboi]

It might be better to use the method in testpath.py for this.

[ono-max]

Good suggestion. I extracted some test path logic and move them to the testpath.py.

[Konboi]

Is there a reason you didn’t use rootDir + title?

[ono-max]

Yes. We can get the full path by using rootDir + title, but we cannot get the relative path from the project/repo root using only those.

As a workaround to get the project/repo root, I'm comparing the configFile against rootDir.

smart-tests-cli/tests/data/playwright/report.json

Line 4 in 74dde1f

"rootDir": "/Users/yabuki-ryosuke/src/github.com/launchableinc/examples/playwright",