@Test
public void testLength() {

   Assert.assertEquals(null, ObjectFunction.length(null));
   Assert.assertEquals(3, ObjectFunction.length("abc"));
   Assert.assertEquals(4, ObjectFunction.length(new Object[] { "abc", null, true, 3 }));
   // not recognized
   Assert.assertEquals(null, ObjectFunction.length(Arrays.<Object> asList("abc", null, true, 3)));
}