test(engine): add predicted-gate golden parity runner (#2286)

[kiannidev]

Summary

• Add committed golden JSON snapshots for every test/fixtures/engine-parity/predicted-gate/ scenario.
• Add test/contract/engine-parity.test.ts asserting buildPredictedGateVerdict (via src/rules/predicted-gate.ts) matches goldens byte-for-byte.
• Add npm run test:engine-parity and wire it into test:ci.
• Add scripts/record-engine-parity-goldens.ts for intentional golden refreshes.

Closes #2286

Conflict avoidance

Touches only test/contract/, test/fixtures/engine-parity/, scripts/record-engine-parity-goldens.ts, and package.json. No overlap with open PRs #3671, #3685, or #3686.

Test plan

• npm run test:engine-parity (9 tests)
• npm run typecheck

Made with Cursor

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[loopover-orb]

Warning

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⏸️ Gittensory review result - manual review recommended

_{Review updated: 2026-07-06 04:10:56 UTC}

11 files · 1 AI reviewer · no blockers · readiness 80/100 · CI green · clean

⏸️ Suggested Action - Manual Review

• Touches a guarded path — held for manual review: This PR changes guardrail-protected path(s): package.json (matched package.json), package.json (matched **/package.json).

Review summary
This PR adds a golden-snapshot regression suite for buildPredictedGateVerdict: 8 committed golden JSON outputs, a vitest parity test that compares live output via toEqual, a recorder script for intentional refreshes, and wiring into test:ci. The mechanics are sound — the recorder and test consume identical fixture data and call the same function with the same argument shape, and the meta-test verifying golden/scenario file-count parity is a nice touch to catch drift when fixtures are added without a golden. One caveat worth flagging: this only guards against future silent drift in buildPredictedGateVerdict's output, not "parity between two implementations" (e.g. extracted vs. original) — worth confirming that's actually what issue #2286 asked for.

Nits — 6 non-blocking

• The PR description calls this a 'byte-for-byte' comparison, but test/contract/engine-parity.test.ts:44 uses `expect(verdict).toEqual(golden)`, which is a structural deep-equal that ignores key ordering — harmless here but the wording overstates what's actually checked.
• test:engine-parity (package.json) runs test/contract/engine-parity.test.ts as its own test:ci step even though test:coverage's default vitest run likely already picks up files under test/contract/, so the suite runs twice per CI pass — matches the existing test:upstream-contract precedent, so not a new pattern, but still worth a comment noting why the duplication is intentional.
• The external IaC scan flagging a 'hardcoded service URL' in clean-pass-oss-anti-slop.json:13 is a false positive — that's a captured golden value of an existing funnel.registerUrl field already emitted by production code, not a new config injection point.
• Confirm in the PR body that issue test(miner-foundation): engine-parity regression runner (assert extracted === original) #2286 is asking for golden-snapshot drift detection (what's built) rather than a live extracted-vs-original engine comparison, since the linked-issue coverage note suggests the original ask may have been for the latter.
• Consider adding a one-line comment in record-engine-parity-goldens.ts warning that re-running it silently overwrites goldens for any behavior change, intentional or not — the test suite alone won't catch a golden that was regenerated to mask a regression.
• Touches a guarded path — held for manual review — A maintainer must review and merge this change.

Signal	Result	Evidence
Code review	✅ No blockers	1 reviewer
Linked issue	✅ Linked	#2286
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	❌ 5/25	Preflight is holding this PR: the review lane is unavailable, so it is not ready for automated review.
Contributor workload	✅ 10/10	Author activity: 1478 registered-repo PR(s), 770 merged, 48 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	kiannidev; Gittensor profile; 1478 PR(s), 48 issue(s).
Gate result	⚠️ Not blocking	Advisory; not blocking this PR.

Review context

• Author: kiannidev
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository registration is not available in the local Gittensory cache.
• Public profile languages: TypeScript, MDX, C++, HTML, Rust
• Official Gittensor activity: 1478 PR(s), 48 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Await review-lane availability.
• Refresh registry data or choose a registered active repo.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.34%. Comparing base (ddf68c3) to head (d4d7f4e).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3687   +/-   ##
=======================================
  Coverage   93.34%   93.34%           
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  Files         315      315           
  Lines       32107    32107           
  Branches    11769    11769           
=======================================
  Hits        29969    29969           
  Misses       1507     1507           
  Partials      631      631           

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