Function expectImageModified

src/test/algorithmTestUtils.ts:86–102

(
  original: ImageData,
  result: ImageData
)

 * Verifies that algorithm modified the input
 */
export function expectImageModified(
  original: ImageData,
  result: ImageData
): void {
  expect(result.width).toBe(original.width);
  expect(result.height).toBe(original.height);
  
  // Check that at least some pixels changed
  let changedPixels = 0;
  for (let i = 0; i < original.data.length; i++) {
    if (original.data[i] !== result.data[i]) {
      changedPixels++;
    }
  }
  
  expect(changedPixels).toBeGreaterThan(0);
}

/**
 * Compares two ImageData objects pixel by pixel