@Test
public void testNullLiteral() {

    String inputExpression = "null";
    BaseNode nullLit = parse( inputExpression );
    assertThat( nullLit, is( instanceOf( NullNode.class ) ) );
    assertThat( nullLit.getResultType(), is( BuiltInType.UNKNOWN ) );
    assertLocation( inputExpression, nullLit );
}