PythonTidy is a code beautifier written three years ago and downloaded
numerous times.

o http://lacusveris.com/PythonTidy/PythonTidy.python

It suffers a bug, which has only recently come to light.  It considers
the following lines equivalent:

  if False is (2 is 3): pass

  if False is 2 is 3: pass

They're not.  PythonTidy handles other non-associative operators such as
division correctly.  I was unable to generalize from arithmetic
operators to comparison operators because the Abstract Syntax Tree (AST)
generated by the *compiler* module returns a different structure for them.  

I tested PythonTidy by running the Python Test Suite (the *test* module
scripts) through it and executing the results, thought I had all my
bases covered because most tests succeeded, and missed this case, so I
am suggesting an amplification of the Python Test Suite for developers
who may be using it for purposes other than testing Python.

I wish to add these lines to the foot of *test_grammar.py*.

  verify(16 // (4 // 2) == 8, '16 // (4 // 2) == 8')
  verify((16 // 4) // 2 == 2, '(16 // 4) // 2 == 2')
  verify(16 // 4 // 2 == 2, '16 // 4 // 2 == 2')
  verify((False is (2 is 3)) == True, '(False is (2 is 3)) == True')
  verify(((False is 2) is 3) == False, '(((False is 2) is 3) == False')
  verify((False is 2 is 3) == False, '(False is 2 is 3) == False')

Please provided a unified diff against the trunk.

You mean like this?

Well, the last two patch files weren't very good, but I hope the third
time's the charm.

That still looks like it's against Python 2.5.

Yet another patch file....

Please just add your test case to the bottom of the trunk...

Sorry I'm having so much trouble with this patch.  Here's another. 
Thanks for your patience.  -ccr-

See how all the other tests in test_grammar are written in a unittest style?

Oh!  That's very different.  :-)

I can do that.

Applied with some changes in r75971.

Thanks.  -ccr-