# Differential verification

Checks a core-v2 implementation against an earlier one (by default `main`)
by driving both with identical randomized inputs and requiring identical
observable results after every step.

From the repository root:

```sh
packages/core-v2/verify/setup-baseline.sh main   # extract into verify/.baseline/
npx vitest run --config packages/core-v2/verify/vitest.config.ts
SEEDS=50 npx vitest run --config packages/core-v2/verify/vitest.config.ts  # quicker
ONLY=rewrite npx vitest bench --run --config packages/core-v2/verify/vitest.config.ts
ONLY=baseline npx vitest bench --run --config packages/core-v2/verify/vitest.config.ts
```

- `scene.diff.ts` runs random `begin`/`update`/`finish`/`cancel`/animation
  frame sequences against both scenes and compares nodes, operations, roots,
  every node's composited style, interactivity, contexts, and every promise
  result. It also compares action-helper output and the runtime export list.
- `gesture.diff.ts` mounts both packages in Vue apps whose views install the
  same gestures (builder definitions, legacy options, `OriginGesture`, and
  `OriginGestureSurface`), dispatches identical random pointer streams, and
  compares scene state and every navigation, start, and completion callback.
- `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.