@Test
 public void EmptyProperties() {
   final MockPropertyPreservingFunction func = getFunction();
   final ValueProperties props = ValueProperties.none();
   final ValueProperties expected = ValueProperties.none();
   assertEqual(expected, func, props);
 }
 @Test
 public void SingleMatchingOtherProperty() {
   final MockPropertyPreservingFunction func = getFunction();
   assertEqual(
       ValueProperties.none(),
       func,
       ValueProperties.builder().with("Z", "A").get(),
       ValueProperties.builder().with("Z", "A").get());
 }