RowPriorityResolver { public void set(final int rowNumber, final int priorityOver) { final RowNumber rowNumberObject = new RowNumber(rowNumber); rowOrder.add(rowNumberObject); if (rowNumber < priorityOver) { throw new IllegalArgumentException("Priority over lower priority rows is not supported."); } if (priorityOver != 0) { overs.put(rowNumberObject, new Over(priorityOver)); } }  void set(final int rowNumber,
                    final int priorityOver); RowPriorities getPriorityRelations();  }
@Test(expected = IllegalArgumentException.class) public void priorityOverLowerRow() throws Exception { rowPriorityResolver.set(1, 4); }