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# Copyright (c) 2009-2012 testtools developers. See LICENSE for details.
__all__ = [
'AfterPreprocessing',
'AllMatch',
'Annotate',
'AnyMatch',
'MatchesAny',
'MatchesAll',
'Not',
]
import types
from ._impl import (
Matcher,
Mismatch,
MismatchDecorator,
)
class MatchesAny(object):
"""Matches if any of the matchers it is created with match."""
def __init__(self, *matchers):
self.matchers = matchers
def match(self, matchee):
results = []
for matcher in self.matchers:
mismatch = matcher.match(matchee)
if mismatch is None:
return None
results.append(mismatch)
return MismatchesAll(results)
def __str__(self):
return "MatchesAny(%s)" % ', '.join([
str(matcher) for matcher in self.matchers])
class MatchesAll(object):
"""Matches if all of the matchers it is created with match."""
def __init__(self, *matchers, **options):
"""Construct a MatchesAll matcher.
Just list the component matchers as arguments in the ``*args``
style. If you want only the first mismatch to be reported, past in
first_only=True as a keyword argument. By default, all mismatches are
reported.
"""
self.matchers = matchers
self.first_only = options.get('first_only', False)
def __str__(self):
return 'MatchesAll(%s)' % ', '.join(map(str, self.matchers))
def match(self, matchee):
results = []
for matcher in self.matchers:
mismatch = matcher.match(matchee)
if mismatch is not None:
if self.first_only:
return mismatch
results.append(mismatch)
if results:
return MismatchesAll(results)
else:
return None
class MismatchesAll(Mismatch):
"""A mismatch with many child mismatches."""
def __init__(self, mismatches, wrap=True):
self.mismatches = mismatches
self._wrap = wrap
def describe(self):
descriptions = []
if self._wrap:
descriptions = ["Differences: ["]
for mismatch in self.mismatches:
descriptions.append(mismatch.describe())
if self._wrap:
descriptions.append("]")
return '\n'.join(descriptions)
class Not(object):
"""Inverts a matcher."""
def __init__(self, matcher):
self.matcher = matcher
def __str__(self):
return 'Not(%s)' % (self.matcher,)
def match(self, other):
mismatch = self.matcher.match(other)
if mismatch is None:
return MatchedUnexpectedly(self.matcher, other)
else:
return None
class MatchedUnexpectedly(Mismatch):
"""A thing matched when it wasn't supposed to."""
def __init__(self, matcher, other):
self.matcher = matcher
self.other = other
def describe(self):
return "%r matches %s" % (self.other, self.matcher)
class Annotate(object):
"""Annotates a matcher with a descriptive string.
Mismatches are then described as '<mismatch>: <annotation>'.
"""
def __init__(self, annotation, matcher):
self.annotation = annotation
self.matcher = matcher
@classmethod
def if_message(cls, annotation, matcher):
"""Annotate ``matcher`` only if ``annotation`` is non-empty."""
if not annotation:
return matcher
return cls(annotation, matcher)
def __str__(self):
return 'Annotate(%r, %s)' % (self.annotation, self.matcher)
def match(self, other):
mismatch = self.matcher.match(other)
if mismatch is not None:
return AnnotatedMismatch(self.annotation, mismatch)
class PostfixedMismatch(MismatchDecorator):
"""A mismatch annotated with a descriptive string."""
def __init__(self, annotation, mismatch):
super(PostfixedMismatch, self).__init__(mismatch)
self.annotation = annotation
self.mismatch = mismatch
def describe(self):
return '%s: %s' % (self.original.describe(), self.annotation)
AnnotatedMismatch = PostfixedMismatch
class PrefixedMismatch(MismatchDecorator):
def __init__(self, prefix, mismatch):
super(PrefixedMismatch, self).__init__(mismatch)
self.prefix = prefix
def describe(self):
return '%s: %s' % (self.prefix, self.original.describe())
class AfterPreprocessing(object):
"""Matches if the value matches after passing through a function.
This can be used to aid in creating trivial matchers as functions, for
example::
def PathHasFileContent(content):
def _read(path):
return open(path).read()
return AfterPreprocessing(_read, Equals(content))
"""
def __init__(self, preprocessor, matcher, annotate=True):
"""Create an AfterPreprocessing matcher.
:param preprocessor: A function called with the matchee before
matching.
:param matcher: What to match the preprocessed matchee against.
:param annotate: Whether or not to annotate the matcher with
something explaining how we transformed the matchee. Defaults
to True.
"""
self.preprocessor = preprocessor
self.matcher = matcher
self.annotate = annotate
def _str_preprocessor(self):
if isinstance(self.preprocessor, types.FunctionType):
return '<function %s>' % self.preprocessor.__name__
return str(self.preprocessor)
def __str__(self):
return "AfterPreprocessing(%s, %s)" % (
self._str_preprocessor(), self.matcher)
def match(self, value):
after = self.preprocessor(value)
if self.annotate:
matcher = Annotate(
"after %s on %r" % (self._str_preprocessor(), value),
self.matcher)
else:
matcher = self.matcher
return matcher.match(after)
# This is the old, deprecated. spelling of the name, kept for backwards
# compatibility.
AfterPreproccessing = AfterPreprocessing
class AllMatch(object):
"""Matches if all provided values match the given matcher."""
def __init__(self, matcher):
self.matcher = matcher
def __str__(self):
return 'AllMatch(%s)' % (self.matcher,)
def match(self, values):
mismatches = []
for value in values:
mismatch = self.matcher.match(value)
if mismatch:
mismatches.append(mismatch)
if mismatches:
return MismatchesAll(mismatches)
class AnyMatch(object):
"""Matches if any of the provided values match the given matcher."""
def __init__(self, matcher):
self.matcher = matcher
def __str__(self):
return 'AnyMatch(%s)' % (self.matcher,)
def match(self, values):
mismatches = []
for value in values:
mismatch = self.matcher.match(value)
if mismatch:
mismatches.append(mismatch)
else:
return None
return MismatchesAll(mismatches)
class MatchesPredicate(Matcher):
"""Match if a given function returns True.
It is reasonably common to want to make a very simple matcher based on a
function that you already have that returns True or False given a single
argument (i.e. a predicate function). This matcher makes it very easy to
do so. e.g.::
IsEven = MatchesPredicate(lambda x: x % 2 == 0, '%s is not even')
self.assertThat(4, IsEven)
"""
def __init__(self, predicate, message):
"""Create a ``MatchesPredicate`` matcher.
:param predicate: A function that takes a single argument and returns
a value that will be interpreted as a boolean.
:param message: A message to describe a mismatch. It will be formatted
with '%' and be given whatever was passed to ``match()``. Thus, it
needs to contain exactly one thing like '%s', '%d' or '%f'.
"""
self.predicate = predicate
self.message = message
def __str__(self):
return '%s(%r, %r)' % (
self.__class__.__name__, self.predicate, self.message)
def match(self, x):
if not self.predicate(x):
return Mismatch(self.message % x)
def MatchesPredicateWithParams(predicate, message, name=None):
"""Match if a given parameterised function returns True.
It is reasonably common to want to make a very simple matcher based on a
function that you already have that returns True or False given some
arguments. This matcher makes it very easy to do so. e.g.::
HasLength = MatchesPredicate(
lambda x, y: len(x) == y, 'len({0}) is not {1}')
# This assertion will fail, as 'len([1, 2]) == 3' is False.
self.assertThat([1, 2], HasLength(3))
Note that unlike MatchesPredicate MatchesPredicateWithParams returns a
factory which you then customise to use by constructing an actual matcher
from it.
The predicate function should take the object to match as its first
parameter. Any additional parameters supplied when constructing a matcher
are supplied to the predicate as additional parameters when checking for a
match.
:param predicate: The predicate function.
:param message: A format string for describing mis-matches.
:param name: Optional replacement name for the matcher.
"""
def construct_matcher(*args, **kwargs):
return _MatchesPredicateWithParams(
predicate, message, name, *args, **kwargs)
return construct_matcher
class _MatchesPredicateWithParams(Matcher):
def __init__(self, predicate, message, name, *args, **kwargs):
"""Create a ``MatchesPredicateWithParams`` matcher.
:param predicate: A function that takes an object to match and
additional params as given in ``*args`` and ``**kwargs``. The
result of the function will be interpreted as a boolean to
determine a match.
:param message: A message to describe a mismatch. It will be formatted
with .format() and be given a tuple containing whatever was passed
to ``match()`` + ``*args`` in ``*args``, and whatever was passed to
``**kwargs`` as its ``**kwargs``.
For instance, to format a single parameter::
"{0} is not a {1}"
To format a keyword arg::
"{0} is not a {type_to_check}"
:param name: What name to use for the matcher class. Pass None to use
the default.
"""
self.predicate = predicate
self.message = message
self.name = name
self.args = args
self.kwargs = kwargs
def __str__(self):
args = [str(arg) for arg in self.args]
kwargs = ["%s=%s" % item for item in self.kwargs.items()]
args = ", ".join(args + kwargs)
if self.name is None:
name = 'MatchesPredicateWithParams(%r, %r)' % (
self.predicate, self.message)
else:
name = self.name
return '%s(%s)' % (name, args)
def match(self, x):
if not self.predicate(x, *self.args, **self.kwargs):
return Mismatch(
self.message.format(*((x,) + self.args), **self.kwargs))
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