If you're testing embedded C systems with browser-based dashboards or control panels, you've hit flaky tests. Guaranteed.

Here's the pattern I see over and over:

The Root Cause Most Engineers Miss

RTOS systems operate on interrupt-driven timing. Your browser tests operate on event-loop timing. These two clocks do not agree, and that's where 80% of flaky failures come from.

Most teams respond by:

• Adding sleep(2000) everywhere ❌

• Re-running failed tests 3x and calling it "retry logic" ❌
  

• Marking tests as @flaky and ignoring them ❌

None of that fixes the actual problem.

What Actually Works

Playwright's Trace Viewer gives you a frame-by-frame replay of exactly what happened during a test run — DOM snapshots, network requests, console logs, and timing data all correlated on a single timeline.

When you compare a passing trace against a failing trace for the same test, the root cause becomes obvious in under 10 minutes. Every time.

What I Teach

I built a course specifically for embedded engineers who need to debug flaky integration tests:

• RTOS-to-browser data flow mapping — understand exactly where timing mismatches occur

• Trace comparison techniques — systematically diff passing vs. failing runs

• CI pipeline hardening — collect traces automatically and build dashboards that catch flakiness before it hits main

• Real patterns — timing assertions, state leakage, interrupt-driven race conditions

14 lessons. 5 chapters. Built from 10+ years of debugging the worst flaky test suites in production RTOS environments.

If you're tired of guessing why tests fail, this is for you.