@Test
public void testScale() {

  final Matrix3 mat3A = new Matrix3( //
      0.01, 0.1, 0.2, //
      1.0, 1.1, 1.2, //
      2.0, 2.1, 2.2);
  final Matrix3 result = mat3A.scale(new Vector3(-1, 2, 3), null);
  assertEquals(new Matrix3( //
      0.01 * -1, 0.1 * 2, 0.2 * 3, //
      1.0 * -1, 1.1 * 2, 1.2 * 3, //
      2.0 * -1, 2.1 * 2, 2.2 * 3), result);
  result.scaleLocal(new Vector3(-1, 0.5, 1 / 3.));
  assertEquals(mat3A, result);
}