are test names really lower case?

[eichin at metacarta.com]

I just generated a large batch of tests (starting with a template test
and a word list, creating a test directory of one test per word,
trivial perl hacking [though the kind of thing that it might be useful
to be able to directly talk to the Database object for, maybe.
direct-xml-mucking works great for now, though]) and noticed that it
simply didn't run any of the tests that began with upper case
letters... I was surprised :-) and now that I try it through the GUI,
it does, in fact, object:

   The name "FRED" is not valid. Names may contain lower-case letters,
   digits, hyphens, underscores, and periods.

I suppose I can come up with some arbitrary quoting, I was just a
little surprised; where does the case-distinction come from? python culture?