show where your regex match assertion failed!
pip install re-assert
re-assert provides a helper class to make assertions of regexes simpler.
re_assert.Matches(pattern: str, *args, **kwargs)
note: under the hood,
re-assert uses the
regex library for matching,
regex.compile supports will work. in general,
regex library is 100% compatible with the
re library (and will even
accept its flags, etc.)
re_assert.Matches.from_pattern(pattern: Pattern[str]) -> Matches
Matches object from an already-compiled regex.
this is useful (for instance) if you're testing an existing compiled regex.
>>> import re >>> reg = re.compile('foo') >>> Matches.from_pattern(reg) == 'fork' False >>> Matches.from_pattern(reg) == 'food' True
the equality operator is overridden for use with assertion frameworks such as pytest
>>> pat = Matches('foo') >>> pat == 'bar' False >>> pat == 'food' True
a side-effect of an equality failure changes the
repr(...) of a
object. this allows for useful pytest assertion messages:
> assert Matches('foo') == 'fork' E AssertionError: assert Matches('foo'...ork\n # ^ == 'fork' E -Matches('foo')\n E - # regex failed to match at:\n E - #\n E - #> fork\n E - # ^ E +'fork'
if you're using some other test framework, this method is useful for producing a readable traceback
>>> Matches('foo').assert_matches('food') >>> Matches('foo').assert_matches('fork') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/home/asottile/workspace/re-assert/re_assert.py", line 63, in assert_matches assert self == s, self._fail AssertionError: regex failed to match at: > fork ^