diff options
Diffstat (limited to 'lib/testtools/testtools/matchers/_datastructures.py')
| -rw-r--r-- | lib/testtools/testtools/matchers/_datastructures.py | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/lib/testtools/testtools/matchers/_datastructures.py b/lib/testtools/testtools/matchers/_datastructures.py new file mode 100644 index 0000000000..70de790738 --- /dev/null +++ b/lib/testtools/testtools/matchers/_datastructures.py @@ -0,0 +1,228 @@ +# Copyright (c) 2009-2012 testtools developers. See LICENSE for details. + +__all__ = [ + 'ContainsAll', + 'MatchesListwise', + 'MatchesSetwise', + 'MatchesStructure', + ] + +"""Matchers that operate with knowledge of Python data structures.""" + +from ..helpers import map_values +from ._higherorder import ( + Annotate, + MatchesAll, + MismatchesAll, + ) +from ._impl import Mismatch + + +def ContainsAll(items): + """Make a matcher that checks whether a list of things is contained + in another thing. + + The matcher effectively checks that the provided sequence is a subset of + the matchee. + """ + from ._basic import Contains + return MatchesAll(*map(Contains, items), first_only=False) + + +class MatchesListwise(object): + """Matches if each matcher matches the corresponding value. + + More easily explained by example than in words: + + >>> from ._basic import Equals + >>> MatchesListwise([Equals(1)]).match([1]) + >>> MatchesListwise([Equals(1), Equals(2)]).match([1, 2]) + >>> print (MatchesListwise([Equals(1), Equals(2)]).match([2, 1]).describe()) + Differences: [ + 1 != 2 + 2 != 1 + ] + >>> matcher = MatchesListwise([Equals(1), Equals(2)], first_only=True) + >>> print (matcher.match([3, 4]).describe()) + 1 != 3 + """ + + def __init__(self, matchers, first_only=False): + """Construct a MatchesListwise matcher. + + :param matchers: A list of matcher that the matched values must match. + :param first_only: If True, then only report the first mismatch, + otherwise report all of them. Defaults to False. + """ + self.matchers = matchers + self.first_only = first_only + + def match(self, values): + from ._basic import Equals + mismatches = [] + length_mismatch = Annotate( + "Length mismatch", Equals(len(self.matchers))).match(len(values)) + if length_mismatch: + mismatches.append(length_mismatch) + for matcher, value in zip(self.matchers, values): + mismatch = matcher.match(value) + if mismatch: + if self.first_only: + return mismatch + mismatches.append(mismatch) + if mismatches: + return MismatchesAll(mismatches) + + +class MatchesStructure(object): + """Matcher that matches an object structurally. + + 'Structurally' here means that attributes of the object being matched are + compared against given matchers. + + `fromExample` allows the creation of a matcher from a prototype object and + then modified versions can be created with `update`. + + `byEquality` creates a matcher in much the same way as the constructor, + except that the matcher for each of the attributes is assumed to be + `Equals`. + + `byMatcher` creates a similar matcher to `byEquality`, but you get to pick + the matcher, rather than just using `Equals`. + """ + + def __init__(self, **kwargs): + """Construct a `MatchesStructure`. + + :param kwargs: A mapping of attributes to matchers. + """ + self.kws = kwargs + + @classmethod + def byEquality(cls, **kwargs): + """Matches an object where the attributes equal the keyword values. + + Similar to the constructor, except that the matcher is assumed to be + Equals. + """ + from ._basic import Equals + return cls.byMatcher(Equals, **kwargs) + + @classmethod + def byMatcher(cls, matcher, **kwargs): + """Matches an object where the attributes match the keyword values. + + Similar to the constructor, except that the provided matcher is used + to match all of the values. + """ + return cls(**map_values(matcher, kwargs)) + + @classmethod + def fromExample(cls, example, *attributes): + from ._basic import Equals + kwargs = {} + for attr in attributes: + kwargs[attr] = Equals(getattr(example, attr)) + return cls(**kwargs) + + def update(self, **kws): + new_kws = self.kws.copy() + for attr, matcher in kws.items(): + if matcher is None: + new_kws.pop(attr, None) + else: + new_kws[attr] = matcher + return type(self)(**new_kws) + + def __str__(self): + kws = [] + for attr, matcher in sorted(self.kws.items()): + kws.append("%s=%s" % (attr, matcher)) + return "%s(%s)" % (self.__class__.__name__, ', '.join(kws)) + + def match(self, value): + matchers = [] + values = [] + for attr, matcher in sorted(self.kws.items()): + matchers.append(Annotate(attr, matcher)) + values.append(getattr(value, attr)) + return MatchesListwise(matchers).match(values) + + +class MatchesSetwise(object): + """Matches if all the matchers match elements of the value being matched. + + That is, each element in the 'observed' set must match exactly one matcher + from the set of matchers, with no matchers left over. + + The difference compared to `MatchesListwise` is that the order of the + matchings does not matter. + """ + + def __init__(self, *matchers): + self.matchers = matchers + + def match(self, observed): + remaining_matchers = set(self.matchers) + not_matched = [] + for value in observed: + for matcher in remaining_matchers: + if matcher.match(value) is None: + remaining_matchers.remove(matcher) + break + else: + not_matched.append(value) + if not_matched or remaining_matchers: + remaining_matchers = list(remaining_matchers) + # There are various cases that all should be reported somewhat + # differently. + + # There are two trivial cases: + # 1) There are just some matchers left over. + # 2) There are just some values left over. + + # Then there are three more interesting cases: + # 3) There are the same number of matchers and values left over. + # 4) There are more matchers left over than values. + # 5) There are more values left over than matchers. + + if len(not_matched) == 0: + if len(remaining_matchers) > 1: + msg = "There were %s matchers left over: " % ( + len(remaining_matchers),) + else: + msg = "There was 1 matcher left over: " + msg += ', '.join(map(str, remaining_matchers)) + return Mismatch(msg) + elif len(remaining_matchers) == 0: + if len(not_matched) > 1: + return Mismatch( + "There were %s values left over: %s" % ( + len(not_matched), not_matched)) + else: + return Mismatch( + "There was 1 value left over: %s" % ( + not_matched, )) + else: + common_length = min(len(remaining_matchers), len(not_matched)) + if common_length == 0: + raise AssertionError("common_length can't be 0 here") + if common_length > 1: + msg = "There were %s mismatches" % (common_length,) + else: + msg = "There was 1 mismatch" + if len(remaining_matchers) > len(not_matched): + extra_matchers = remaining_matchers[common_length:] + msg += " and %s extra matcher" % (len(extra_matchers), ) + if len(extra_matchers) > 1: + msg += "s" + msg += ': ' + ', '.join(map(str, extra_matchers)) + elif len(not_matched) > len(remaining_matchers): + extra_values = not_matched[common_length:] + msg += " and %s extra value" % (len(extra_values), ) + if len(extra_values) > 1: + msg += "s" + msg += ': ' + str(extra_values) + return Annotate( + msg, MatchesListwise(remaining_matchers[:common_length]) + ).match(not_matched[:common_length]) |