@Test
    public void shouldHandleAllNullInput() {
        assertNull(add(null, null));
        assertNull(sub(null, null));
        assertNull(mul(null, null));
        assertNull(div(null, null));
        assertNull(max((Number) null, null));
        assertNull(max((Comparable) null, null));
        assertNull(min((Number) null, null));
        assertNull(min((Comparable) null, null));
        assertEquals(0, compare(null, null).intValue());
    }
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/util/NumberHelperTest.java