# Benchmarks

Compares core-v2's performance against an earlier implementation (by default
`main`).

From the repository root:

```sh
packages/core-v2/verify/setup-baseline.sh main   # extract into verify/.baseline/
ONLY=baseline npx vitest bench --run --config packages/core-v2/verify/vitest.config.ts
ONLY=rewrite npx vitest bench --run --config packages/core-v2/verify/vitest.config.ts
```

`scene.bench.ts` measures compositing, push/back cycles, and rendered frames.
Run each implementation in its own process with `ONLY=`; running both in one
process biases whichever runs second.

Behavioural verification lives with the unit tests: `tests/property.test.ts`
drives random operation sequences and pointer streams and checks the scene's
structural invariants after every step. Set `PROPERTY_SEEDS` to run more.

## Real-browser feel tests

`browser/` drives a development build in Chromium with emulated touch input,
which happy-dom cannot model: implicit touch pointer capture, native
scrolling, `pointercancel`, frame timing, and rendered styles. It checks:

- **recognition** on human-like traces: wobbly and diagonal starts, a small
  wind-up the wrong way, a twitch at lift-off, slow and short drags, flicks,
  and vertical scrolls that must not trigger gestures;
- **frame pacing** while a finger drags (p95 ≤ 20ms, ≤ 5% of frames over
  20ms) for a horizontal swipe and a scroll-edge dismiss;
- **behaviour**: swipes over nested scrollers, native scrolling beside
  gestures, scroll-edge dismissal, `onCommit` inside `pointerup`, and the
  development continuity warning.

```sh
npm run test:feel
```

Set `CHROMIUM_PATH` to use a Chromium other than Playwright's own.