Fix coordination window watcher test

[mswilkison]

Fixes #4004.

Summary

• Replaces the 1ms ticker simulation in TestWatchCoordinationWindows with direct block injection.
• Keeps coverage for non-window blocks, duplicate window blocks, and the expected 900/1800 coordination windows without relying on wall-clock block generation.

Validation

• go test ./pkg/tbtc -run TestWatchCoordinationWindows -count=1
• go test ./pkg/tbtc

Summary by CodeRabbit

• Tests
  • Improved test determinism and reliability for coordination window validation by removing time-dependent blocking mechanisms and introducing controlled block sequencing.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 3b085be0-b636-48bc-9f27-c6102617f2e6

📥 Commits

Reviewing files that changed from the base of the PR and between 980587b and de40ab1.

📒 Files selected for processing (1)

• pkg/tbtc/coordination_test.go

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📝 Walkthrough

Walkthrough

The test TestWatchCoordinationWindows is refactored to eliminate non-deterministic timing by exposing a controllable block channel to the test fixture and removing the internal ticker goroutine. It now uses a cancelable context, deterministic helper functions to send blocks and assert window emissions, and explicit selection logic instead of polling loops.

Changes

Test Determinism Refactor

Layer / File(s)

Summary

Deterministic coordination window test pkg/tbtc/coordination_test.go

TestWatchCoordinationWindows removes non-deterministic goroutine/ticker block generation and replaces it with explicit sendBlock and expectWindow helpers that use select + time.After to control test flow. The watchBlocksFn fixture now returns a controllable blocksChan instead of auto-generating blocks until context timeout. Test assertion switches from polling-loop collection of windows to deterministic per-block window validation for coordination windows 900 and 1800.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A channel's path now cleared and free,
No ticker tick to hide the spree—
With helpers bold to guide each test,
Coordination windows shine their best!
Determinism blooms at last, 🌸

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: fixing the TestWatchCoordinationWindows test by replacing a flaky ticker-based approach with direct block injection.
Linked Issues check	✅ Passed	The PR directly addresses issue #4004 by fixing the standalone test failure through refactoring the test to use deterministic block injection instead of wall-clock timing.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the coordination window watcher test as required by issue #4004; no unrelated modifications are present.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/fix-coordination-window-test

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