Test coverage report incomplete for apex test retries

[aspagni]

Describe the bug
When running the sfp apextests trigger command, if there are LOCKED_ROW errors due to parallel testing, the failed tests rerun in serial mode (and that works fine).
Issue is that, within the .test results folder, only the test-result-[runId]-coverage.json for the second serial run is saved.
This does not allow to have a full picture of the code coverage report (i.e. to send it to sonarqube).

Other files in the .testresults folder (junit and JSON) keep track of both test runs, only the coverage one loses track of the original parallel run (see screenshot)

To Reproduce
Run sfp apextests trigger in a repository where LOCKED_ROW error happens and gets retried.
Check generated coverage file in .testresults folder

Expected behavior
Either merge the coverage for both files into a single one, or at least persist the original one.

Screenshots

The XML file shows that two runs happened (and they are somehow merged into a single one, see the two IDs in the name file)

Platform Details:

• OS: Windows
• Version sfp/36.0.9
• Salesforce CLI(sfdx cli) Version: 2.22.7
• CI Platform: locally

Additional context
Add any other context about the problem here.

[dieffrei]

@azlam-abdulsalam code coverage result from the first run is merged into second file per design.
Is there any special reason for that?
Or shall we keep them separated?

[aspagni]

Just be clear, the issue is not with the files being merged, but with the actual content of the file, which only contains test results from the second run