test: use a more reliable service pid detection

[reubenmiller]

Proposed changes

Due to some flake-finder runs, it was found that the assertions which rely on getting a service's main PID can suffer from race conditions if there is a delay between starting a service and getting the pid via pgrep. Instead the Service Should Be Running keyword also returns the PID of the running service, so it does not assume that the service is running "now", but will wait if necessary if the service is not already running.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
390	0	3	390	100	57m2.546999999s

[didier-wenzek]

Approved