@Test
public void testCompareNullKey() throws Exception
{

    // Two null objects are equal.
    assertEquals(0, comparator.compare(null, null));
    // Null is less than an object.
    assertEquals(-1, comparator.compare(null, new BusinessObjectDataKey()));
    // An object is greater than null.
    assertEquals(1, comparator.compare(new BusinessObjectDataKey(), null));
}