Logged In: YES 
user_id=6380

The test seems fine, and a good addition.  Don't worry too
much about how to report the failure (though perhaps
including the key word "subtype" in the error output might
help).

I noticed that when I change the Unicode function fixup() to
not do a check for subclasses, I only get very few failures:
one for capitalize, two for lower, one for upper. I think
this is because the test suite doesn't have enough sample
cases where the output is the same as the input. Maybe some
could be added.

But go ahead and check in diff3.txt.