@Test
 public void isMovedBeforeIfLocationIsBefore() throws Exception {
   plotPartMove.moveTo(RelativeLocation.Before);
   assertArrayEquals(new PlotPart[] {laterChild, formerChild, middleChild}, parent.getChildren());
 }
 @Test
 public void isValidForAllLocations() throws Exception {
   assertTrue(plotPartMove.isValid());
 }