test(cloudxr): fix flaky cmdline-read race in test_background.py

[gareth-morgan-nv]

Summary

Fixes an intermittent CI failure in test_recognises_a_service_under_any_shipped_module_name, which fails with AssertionError: assert None == <pid> roughly 1 in 10 runs.

What changed

• background.read_pid() reads /proc/<pid>/cmdline immediately after subprocess.Popen() returns, but on a loaded runner the child's /proc entry isn't guaranteed to be populated that instantly.
• The test now polls read_pid() for up to 2 seconds instead of asserting on the very first read.

Validation

• Confirmed this is a genuine, pre-existing race unrelated to any in-flight PR — reproduced the identical failure on unmodified main (commit 6960d4a59) and on test(cloudxr): reusable fake-adb test double (FakeAdb/mock_adb) #1147 (which doesn't touch background.py at all).
• Reproduced the failure locally on the original test: ~11% failure rate across 70 runs (4 failures / 30 + 40 runs), hitting both the isaaccapture.cloudxr.service and legacy isaacteleop.cloudxr.service parametrizations roughly evenly — confirms it's a genuine timing race, not specific to either module string.
• Stress-tested the fixed test: 60/60 passed, 0 failures, same machine/loop.
• ruff check / ruff format --check clean.
• pre-commit run (matching CI's SKIP=check-copyright-year hook set) clean.

Known limitations / follow-ups

None — this is a minimal, targeted fix to the test's own timing assumption; background.py's production logic is untouched.

Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com

Summary by CodeRabbit

• Tests
  • Updated automated checks to allow background processes time to start before verifying service recognition. This makes the check more resilient to startup timing differences while preserving the same expected behavior. No end-user functionality or behavior has changed.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository: NVIDIA/IsaacCapture/.coderabbit.yaml
• Review profile: CHILL
• Plan: Enterprise
• Run ID: 96fbe4cb-231a-4143-82f2-0b2f0623b81d

📥 Commits

Reviewing files that changed from the base of the PR and between bb59d39 and 7f36a22.

📒 Files selected for processing (1)

• tests/python/core/cloudxr/test_background.py

Included review availability: This review used your included allowance. Your plan provides up to 12 included reviews per hour; 11 remain after this review.

---

📝 Walkthrough

Walkthrough

The service-recognition test now polls background.read_pid() for up to two seconds. It waits 50 ms between reads and then asserts that the returned PID matches the spawned process.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~5 minutes

Merge Risk: ⚪ Minimal · up to 7f36a

No merge-blocking risk is identified in the described test-only change.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the CloudXR test and the flaky command-line read race it fixes. It matches the main change in the pull request.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

---

_{Comment @coderabbitai help to get the list of available commands.}