Hi,
Despite being touted as one of its strengths, I think the output on
comparison of complex objects could use some work. I work with many
tests that compare dictionaries for example ('assert result ==
expected'), and if they fail I usually have to dig around, manually
iterate through them etc to figure out where the difference is.
Here is an example.
tests/unit/formatters/test_WxPhrase.py:638: in
test_mergeBackSeparableAttributesMultipleSentencesOK
> assert result == expected
E assert {frozenset(['...00:00 GMT))]]} == {frozenset(['T...00:00 GMT))]]}
E Skipping 161 identical leading characters in diff
E 00 GMT))]]}
Note using --tb=long does not expand the diff text -- it just expands
the traceback stack which is not helpful in this case.
If I use the compare() method in testfixtures library instead of a
plain assert statement, the output is a bit better:
tests/unit/formatters/test_WxPhrase.py:639: in
test_mergeBackSeparableAttributesMultipleSentencesOK
> compare(result, expected)
../GFESuite-Builds/Release/release/lib/python2.7/site-packages/testfixtures/comparison.py:268:
in compare
> raise AssertionError(message)
E AssertionError: dict not as expected:
E
E values differ:
E frozenset(['TS']): [[WxStatBlock((Jan 01 70 16:00:00 GMT, Jan
01 70 22:00:00 GMT))],
E [WxStatBlock((Jan 01 70 10:00:00 GMT, Jan 01 70 16:00:00
GMT))]] != [[WxStatBlock((Jan 01 70 16:00:00 GMT, Jan 01 70 22:00:00
GMT))],
E [WxStatBlock((Jan 01 70 10:00:00 GMT, Jan 01 70 16:00:00 GMT))]]
OK - now I can see that the assert is failing because the order is different.
Is there a way, or could one be added, to be more verbose in object
(esp. list/set/dict) comparison? An option like --cmp=verbose (or
maybe it makes sense incorporated into --tb=long??)
I had a half-hearted attempt at writing my own
pytest_assertrepr_compare to use this compare() method (I really like
using natural assert statements) but py.test didn't seem to pick it
up. I might investigate this further but also maybe this is a good
area for pytest to improve?
thanks,
Brianna
--
They've just been waiting in a mountain for the right moment:
http://modernthings.org/
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