fix: measure upload and latency without server timing

[mktbsh]

Summary

• Measure upload throughput from the client request write timing.
• Fall back to end-to-end timing when request write timing is unavailable.
• Fall back to client TTFB for unloaded latency when cfRequestDuration is absent.
• Add regression coverage for the current Cloudflare response headers.

Root cause

Cloudflare's current speed-test responses no longer include the cfRequestDuration server-timing entry that the CLI treated as required for latency and upload calculations. The CLI therefore rejected all unloaded latency samples and could report an upload value of 0.00 Mbps.

Validation

• go test ./... (70 tests passed)
• go vet ./...
• go mod verify
• go build -trimpath -ldflags='-s -w' -o dist/unispeedtest ./cmd/unispeedtest
• Built binary -json run completed with positive upload throughput (2558.96 Mbps) and valid JSON output.

Summary by CodeRabbit

• Bug Fixes
  • Improved latency and upload timing measurements using client-side request timing when available.
  • Added reliable fallbacks when timing data is unavailable or invalid.
  • Corrected fallback warning behavior for upload measurements.

[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: 8d0c4ae4-f421-47be-9edd-4425dae37bfb

📥 Commits

Reviewing files that changed from the base of the PR and between fef5618 and 9ff7dc6.

📒 Files selected for processing (2)

• internal/cloudflare/measure.go
• internal/cloudflare/upload_test.go

🚧 Files skipped from review as they are similar to previous changes (2)

• internal/cloudflare/upload_test.go
• internal/cloudflare/measure.go

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📝 Walkthrough

Walkthrough

The Cloudflare client now records successful request-write time. Upload measurement uses this timing when available. Latency measurement falls back to validated client timing. Tests cover delayed transmission, delayed first-byte receipt, and fallback warnings.

Changes

Cloudflare timing measurement

Layer / File(s)	Summary
Request-write timing capture internal/cloudflare/types.go, internal/cloudflare/client.go	PerfData stores RequestWritten. The HTTP trace records it only after a successful request write.
Client-side measurement fallbacks internal/cloudflare/measure.go	Latency measurement validates client timing. Upload measurement prefers request-write duration and falls back to end-to-end duration with a warning.
Timing behavior tests internal/cloudflare/upload_test.go, internal/cloudflare/client_test.go	Tests cover delayed request transmission, delayed first-byte receipt, positive client timing, and the updated fallback warning count.

Estimated code review effort: 3 (Moderate) | ~20 minutes

🚥 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 clearly summarizes the main change: measuring upload and latency without relying on server timing.
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 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch agent/fix-upload-speed-measurement

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@internal/cloudflare/measure.go`:
- Around line 65-70: Validate serverTiming immediately after ParseServerTiming
in the measurement flow: if it is NaN, infinite, or negative, return
clientDuration with no error. Preserve the existing parse-error fallback and
only calculate dur after the parsed timing passes these checks.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: cc9dc6be-a42a-48ff-9c52-e1c845647b0a

📥 Commits

Reviewing files that changed from the base of the PR and between 7b016f9 and fef5618.

📒 Files selected for processing (5)

• internal/cloudflare/client.go
• internal/cloudflare/client_test.go
• internal/cloudflare/measure.go
• internal/cloudflare/types.go
• internal/cloudflare/upload_test.go