@Test
public void testScale() {

  final Matrix4 mat4A = new Matrix4( //
      0.01, 0.1, 0.2, 0.3, //
      1.0, 1.1, 1.2, 1.3, //
      2.0, 2.1, 2.2, 2.3, //
      3.0, 3.1, 3.2, 3.3);
  final Matrix4 result = mat4A.scale(new Vector4(-1, 2, 3, 4), null);
  assertEquals(new Matrix4( //
      0.01 * -1, 0.1 * 2, 0.2 * 3, 0.3 * 4, //
      1.0 * -1, 1.1 * 2, 1.2 * 3, 1.3 * 4, //
      2.0 * -1, 2.1 * 2, 2.2 * 3, 2.3 * 4, //
      3.0 * -1, 3.1 * 2, 3.2 * 3, 3.3 * 4), result);
  result.scaleLocal(new Vector4(-1, 0.5, 1 / 3., .25));
  assertEquals(mat4A, result);
}