refactor(core): extract maxEndTime+serialize to parsers/test-utils.ts (TU) (#1261)

* test(studio): add T5b rotation+motion build-patches characterization

Extends manualEditsDomPatches.test.ts with rotation and motion pairs.
Same 4-pattern structure: populated, empty, clear restores originals,
build/clear symmetry. Merges duplicate manualEditsTypes import block.

* test(studio): add T5c review-fix gaps in manualEditsDomPatches characterization

Fixes four gaps identified in max-setting code review:
- Box-size clear: replace arrayContaining with full ordered toEqual (30 ops)
- Box-size / pathOffset / rotation clear: add empty-string coercion tests
  (origVal||null must produce null, not set property to "")
- Rotation clear: add test for absent STUDIO_ORIGINAL_ROTATION_TRANSFORM_ORIGIN_ATTR
- Motion clear: prove input-independence by calling with both empty and populated
  element and asserting identical output

* refactor(core): extract maxEndTime+serialize to parsers/test-utils.ts (TU)

Deduplicate helpers shared by T1 (htmlParser.roundtrip.test.ts) and T2
(stableIds.test.ts). Both files inline identical implementations; extract
to test-utils.ts so future parser tests (T6a…) import one copy.

Also fix lefthook fallow command to unset GIT_DIR+GIT_INDEX_FILE before
running — those vars are set by git in worktree hook context and block
fallow’s internal temp-worktree creation.

lefthook.yml

@@ -19,7 +19,10 @@ pre-commit:
     # fails on issues introduced by the branch, not inherited findings.
     fallow:
       glob: "packages/**/*.{ts,tsx,mts,cts,js,jsx,mjs,cjs}"
-      run: bunx fallow audit --base origin/main --fail-on-issues
+      # Unset git worktree env vars: fallow creates a temp worktree internally and
+      # GIT_DIR/GIT_INDEX_FILE (set by git in worktree hook context) break that.
+      # env -u is safe in non-worktree contexts (no-op when var is unset).
+      run: env -u GIT_DIR -u GIT_INDEX_FILE -u GIT_WORK_TREE bunx fallow audit --base origin/main --fail-on-issues
     filesize:
       # Scoped to packages/studio — the 600 LOC limit is a studio architecture
       # standard enforced as part of the App.tsx decomposition work. Player and

packages/core/src/parsers/htmlParser.roundtrip.test.ts

@@ -9,25 +9,8 @@ import { existsSync, readdirSync, readFileSync } from "node:fs";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 import { parseHtml } from "./htmlParser.js";
+import { maxEndTime, serialize } from "./test-utils.js";
 import { generateHyperframesHtml } from "../generators/hyperframes.js";
-import type { ParsedHtml } from "./htmlParser.js";
-
-function maxEndTime(elements: ParsedHtml["elements"]): number {
-  if (elements.length === 0) return 0;
-  return Math.max(...elements.map((e) => e.startTime + e.duration));
-}
-
-function serialize(parsed: ParsedHtml): string {
-  // Fixed compositionId prevents Date.now() churn from masking structural instability.
-  // The compositionId generation instability itself is tracked as R1 (stable hf- ids).
-  return generateHyperframesHtml(parsed.elements, maxEndTime(parsed.elements), {
-    compositionId: "test-comp",
-    resolution: parsed.resolution,
-    styles: parsed.styles ?? undefined,
-    keyframes: parsed.keyframes,
-    stageZoomKeyframes: parsed.stageZoomKeyframes,
-  });
-}
 
 describe("T1 — parse→serialize round-trip (DOM/timing)", () => {
   it("preserves element count and ids through one round-trip", () => {

packages/core/src/parsers/stableIds.test.ts

@@ -13,23 +13,7 @@
  */
 import { describe, expect, it } from "vitest";
 import { parseHtml } from "./htmlParser.js";
-import { generateHyperframesHtml } from "../generators/hyperframes.js";
-import type { ParsedHtml } from "./htmlParser.js";
-
-function maxEndTime(elements: ParsedHtml["elements"]): number {
-  if (elements.length === 0) return 0;
-  return Math.max(...elements.map((e) => e.startTime + e.duration));
-}
-
-function serialize(parsed: ParsedHtml): string {
-  return generateHyperframesHtml(parsed.elements, maxEndTime(parsed.elements), {
-    compositionId: "test-comp",
-    resolution: parsed.resolution,
-    styles: parsed.styles ?? undefined,
-    keyframes: parsed.keyframes,
-    stageZoomKeyframes: parsed.stageZoomKeyframes,
-  });
-}
+import { serialize } from "./test-utils.js";
 
 describe("T2 — stable element ids (spec for R1)", () => {
   // --- Spec (red until R1) ---

packages/core/src/parsers/test-utils.ts

@@ -0,0 +1,28 @@
+/**
+ * Shared test utilities for parser test suites (T1, T2, T6…).
+ * Import from here rather than duplicating helpers across test files.
+ *
+ * Not part of the public package exports — consumed only by *.test.ts files.
+ */
+import { generateHyperframesHtml } from "../generators/hyperframes.js";
+import type { ParsedHtml } from "./htmlParser.js";
+
+export function maxEndTime(elements: ParsedHtml["elements"]): number {
+  if (elements.length === 0) return 0;
+  return Math.max(...elements.map((e) => e.startTime + e.duration));
+}
+
+/**
+ * Round-trip serialize helper.
+ * Fixed compositionId prevents Date.now() churn from masking structural instability.
+ * The compositionId generation instability itself is tracked as R1 (stable hf- ids).
+ */
+export function serialize(parsed: ParsedHtml): string {
+  return generateHyperframesHtml(parsed.elements, maxEndTime(parsed.elements), {
+    compositionId: "test-comp",
+    resolution: parsed.resolution,
+    styles: parsed.styles ?? undefined,
+    keyframes: parsed.keyframes,
+    stageZoomKeyframes: parsed.stageZoomKeyframes,
+  });
+}

packages/core/tsconfig.json

@@ -15,5 +15,12 @@
   },
   "files": ["src/runtime/mediaVolumeEnvelope.ts"],
   "include": ["src/**/*"],
-  "exclude": ["node_modules", "dist", "src/tests", "src/runtime", "**/*.test.ts"]
+  "exclude": [
+    "node_modules",
+    "dist",
+    "src/tests",
+    "src/runtime",
+    "**/*.test.ts",
+    "src/parsers/test-utils.ts"
+  ]
 }