test: NonScalingOverlay + ReactNativeZoomableView test suite (274 tests, 29 suites)

[thomasttvo]

Summary

Adds a Jest + React Testing Library test suite covering NonScalingOverlay, renderOverlay integration, and the full SPECS.md contract for ReactNativeZoomableView. 274 tests across 29 suites, all green locally.

Targets thomas/nonscaling-overlay (PR #178) — when #178 merges to master, this PR's base auto-updates and the tests come along.

Test coverage

• 14 EC-NSO edge cases from PR Reanimated #151's review (translated from prose into regression tests).
• 151 SPEC items from SPECS.md (with documented device-only and type-only gaps).
• PR Reanimated #151 thread regressions: doubleTapZoomToCenter math (#3179084848), spurious-tap on cancel (#3179193006), settle double-fire (#3164939942), pinProps spread (#3107340687 / #3179480336), useLatestWorklet stale closure (#3179033549 / #3238350220), and others.

Suite breakdown

Suite	Tests	Surface
computeOverlayTransform.test.ts	9	Pure transform-math helper
NonScalingOverlay.test.tsx	9	Overlay component (RTL + reanimated mock)
renderOverlay.test.tsx	6	RNZV.renderOverlay integration
helper/__tests__/* (9 files)	51	Pure math helpers + 4 new extractions
RNZV.{props,imperativeHandle,callbacks}.test.tsx	57	Defaults, methods, callbacks (no gesture)
RNZV.{staticPin,feedback}.test.tsx + useLatestWorklet.test.ts	25	Static pin, debug, hook ref identity
treeShape.test.tsx + StaticPin.styling.test.tsx	17	Tree topology + StaticPin pointerEvents/styling
gestures/* (5 files)	82	Direct gesture-handler invocation via getByGestureTestId('canvas-gesture') (tap, double-tap, long-press, pinch, shift, multi-finger, pan-responder callbacks, intercept)

Test infrastructure (commit e76d21f)

• Jest 29, @testing-library/react-native@^12.5.0, react-test-renderer@18.3.1, babel-jest, @types/jest.
• jest.setup.ts wires react-native-reanimated/mock + react-native-gesture-handler/jestSetup.
• Custom RNGH Gesture.Manual() mock with a withTestId registry (Path 2 from research) so gesture-driven tests can invoke onTouchesDown/Move/Up/Cancelled directly under reanimated/mock.
• New CI step in .github/workflows/lint.yml: yarn test --ci --runInBand.

Pure-helper extractions (non-behavior-changing)

4 inline expressions in ReactNativeZoomableView.tsx extracted to src/helper/ for unit-testability — math is byte-equivalent to the inline original:

• calcShiftDelta (from _calcOffsetShiftSinceLastGestureState)
• applyPinchSensitivity (from _handlePinching resistance math)
• clampZoom (pinch-frame clamp; publicZoomTo's reject-on-out-of-range was left untouched — different semantics)
• shouldSkipShift (pan-gate predicate)

SPECS.md changes

• New section ## NonScalingOverlay contract codifying the prop shape, 5-element transform formula, static-style rules, mount-order rules, and wrapperSize mirror semantics.

Known gaps (documented in phase5-specs-research.md §5)

• Device-only items: GHRV mount requirement, FP-drift bypass of disablePanOnInitialZoom, native momentum absence, dual-version Reanimated matrix (Elliott's #3691782346).
• Type-only SPECs covered by tsc --noEmit in CI (no expect-type/tsd dep added).
• Mock-fidelity caveats: assertions are on JS-thread callback fires rather than intermediate SharedValue trajectories; withTiming/cancelAnimation/runOnUI are no-ops under the mock.

Test plan

• Reviewer runs yarn test locally and confirms 29 suites / 274 tests pass.
• CI's Run unit tests step passes on push.
• Spot-check a few it('SPEC-NNN: …', …) cases to confirm SPEC IDs map to the items in SPECS.md.

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Primarily adds unit/integration tests and Jest infrastructure; the only runtime-impactful changes appear to be small helper extractions for testability, which are low risk but could subtly affect gesture math if not truly equivalent.

Overview
Adds a comprehensive Jest + React Testing Library test suite covering NonScalingOverlay, renderOverlay integration, gesture flows, and the documented SPECS.md contract for ReactNativeZoomableView.

Introduces supporting test infrastructure (Jest config/setup and gesture-handler/reanimated mocking) and extracts a few inline math/predicate helpers into src/helper/ to make the behavior unit-testable without intended runtime behavior changes.

^{Reviewed by Cursor Bugbot for commit 270d5fc. Configure here.}

[thomasttvo]

Superseded by PR for thomas/zoomable-tests-v2 — original branch had merge-base issue making the diff empty in GitHub's view. Replacement PR rooted at b8a6df6 so the diff displays correctly.