[Python-Dev] PEP: Frequently-requested additional features for the unittest module (original) (raw)

Ben Finney ben+python at benfinney.id.au
Wed Jul 16 15:36:32 CEST 2008

Scott David Daniels <Scott.Daniels at Acm.Org> writes:

I would rather something more like:

def assertcomparetrue(op, first, second, msg=None): if op(first, second): return raise self.failureexception(msg) if msg is None: self.failureexception("%(first)r %(op)r %(second)" % vars()) self.failureexception("%(first)r %(op)r %(second): %(msg)" % vars())

I'm confused. It appears to me that your version never gets past the first 'raise' statement, which is unconditional; and the rest seems to do nothing but instantiate exceptions without using them.

Do you perhaps mean something like this::

def assert_compare_true(op, first, second, msg=None):
    fail_detail = "%(first)r %(op)r %(second)r" % vars()
    if msg is None:
        msg = fail_detail
    else:
        msg = "%(fail_detail)s: %(msg)s" % vars()
    if not op(first, second):
        raise self.failure_exception(msg)

If so, that sems to be in line with the "Enhanced failure message" principle exercised elsewhere in the same PEP, i.e. that the failure message should always contain certain information, even if a message is specified by the caller.

One downside I can see is that, in optimising for this common case, it makes the function useless to someone who wants to specify their own failure message exactly, without the specific extra information in that specific format.

What do others think of this?

-- \ “Holy contributing to the delinquency of minors, Batman!” —Robin | `\ | o_) | Ben Finney

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