@Test
public void testOneNull() {

    IDifference result = AtomTypeHybridizationDifference.construct("Foo", null, IAtomType.Hybridization.SP1);
    Assert.assertNotNull(result);
    result = AtomTypeHybridizationDifference.construct("Foo", IAtomType.Hybridization.SP1, null);
    Assert.assertNotNull(result);
}