static ImageSurface test_ScanlineBitMatrix() {
  var m = randomBitMatrix(8, 8);
  print(m);
  var m2 = ScanlineBitMatrix(m);
  printStructIndented(m2);
  assertTrue(matricesEqual(m, m2));
  ret pixelatedZoomedImageSurface(bitMatricesToImage(m, m2));
}