[Python-Dev] Proposed unittest changes

Neal Norwitz nnorwitz at gmail.com
Fri Apr 25 06:49:24 CEST 2008

[Michael working on cleaning up the unittest module]

it seems like most of the good ideas have been captured already.  I'll
through two more (low priority) ideas out there.

 1) Randomized test runner/option that runs tests in a random order
(like regrtest.py -r, but for methods)
 2) decorator to verify a test method is supposed to fail

#2 is useful for getting test cases into the code sooner rather than
later.  I'm pretty sure I have a patch that implements this
(http://bugs.python.org/issue1399935).  It didn't fit in well with the
old unittest structure, but seems closer to the direction you are

One other idea that probably ought not be done just yet:  add a way of
failing with the test continuing.  We use this at work (not in Python
though) and when used appropriately, it works quite well.  It provides
more information about the failure.  It looks something like this:

  def testMethod(self):
    # setup
    self.expectEqual(expected_result, other_value)

All the expect methods duplicate the assert methods.  Asserts can the
test to fail immediately, expects don't fail immediately allowing the
test to continue.  All the expect failures are collected and printed
at the end of the method run.  I was a little skeptical about assert
vs expect at first, but it has proven useful in the long run.  As I
said, I don't think this should be done now, maybe later.


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