import { test } from 'node:test';
import assert from 'node:assert/strict';
import { pinchZoom } from './usePinchZoom';

test('pinchZoom scales with finger distance', () => {
  assert.equal(pinchZoom(100, 1, 200), 2);
  assert.equal(pinchZoom(100, 2, 150), 3);
  assert.equal(pinchZoom(200, 3, 100), 1.5);
});

test('pinchZoom clamps to 1×–5×', () => {
  assert.equal(pinchZoom(100, 1, 1000), 5);
  assert.equal(pinchZoom(100, 1, 20), 1);
});

test('pinchZoom snaps near 1× and ignores a zero start', () => {
  assert.equal(pinchZoom(100, 1, 105), 1);
  assert.equal(pinchZoom(100, 2, 52), 1);
  assert.equal(pinchZoom(0, 1.7, 120), 1.7);
});