@Test
public void testInvert() {

  final Transform trans1 = new Transform();
  trans1.setRotation(new Matrix3().applyRotationZ(3 * MathUtils.QUARTER_PI));
  final Transform trans2 = trans1.invert(null);
  assertEquals(Transform.IDENTITY, trans1.multiply(trans2, null));
  trans1.setIdentity().invert(trans1);
  assertEquals(Transform.IDENTITY, trans1);
}