@Test
 public void testAssertThat_child_at_property_path_does_exist_succeeds_when_child_exists() {
   final ObjectWithString working = new ObjectWithString("foo");
   final ObjectWithString base = new ObjectWithString("bar");
   final Node node = ObjectDifferFactory.getInstance().compare(working, base);
   assertThat(node).child(PropertyPath.buildWith("value")).doesExist();
 }
 @Test(expected = AssertionError.class)
 public void testAssertThat_child_at_property_path_does_exist_fails_when_child_doesnt_exist() {
   assertThat(null).child(PropertyPath.buildWith("value")).doesExist();
 }