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diff --git a/lib/subunit/python/testtools/matchers.py b/lib/subunit/python/testtools/matchers.py
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+++ b/lib/subunit/python/testtools/matchers.py
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+# Copyright (c) 2009 Jonathan M. Lange. See LICENSE for details.
+
+"""Matchers, a way to express complex assertions outside the testcase.
+
+Inspired by 'hamcrest'.
+
+Matcher provides the abstract API that all matchers need to implement.
+
+Bundled matchers are listed in __all__: a list can be obtained by running
+$ python -c 'import testtools.matchers; print testtools.matchers.__all__'
+"""
+
+__metaclass__ = type
+__all__ = [
+    'DocTestMatches',
+    'Equals',
+    'MatchesAny',
+    ]
+
+import doctest
+
+
+class Matcher:
+    """A pattern matcher.
+
+    A Matcher must implement match and __str__ to be used by
+    testtools.TestCase.assertThat. Matcher.match(thing) returns None when
+    thing is completely matched, and a Mismatch object otherwise.
+
+    Matchers can be useful outside of test cases, as they are simply a
+    pattern matching language expressed as objects.
+
+    testtools.matchers is inspired by hamcrest, but is pythonic rather than
+    a Java transcription.
+    """
+
+    def match(self, something):
+        """Return None if this matcher matches something, a Mismatch otherwise.
+        """
+        raise NotImplementedError(self.match)
+
+    def __str__(self):
+        """Get a sensible human representation of the matcher.
+
+        This should include the parameters given to the matcher and any
+        state that would affect the matches operation.
+        """
+        raise NotImplementedError(self.__str__)
+
+
+class Mismatch:
+    """An object describing a mismatch detected by a Matcher."""
+
+    def describe(self):
+        """Describe the mismatch.
+
+        This should be either a human-readable string or castable to a string.
+        """
+        raise NotImplementedError(self.describe_difference)
+
+
+class DocTestMatches:
+    """See if a string matches a doctest example."""
+
+    def __init__(self, example, flags=0):
+        """Create a DocTestMatches to match example.
+
+        :param example: The example to match e.g. 'foo bar baz'
+        :param flags: doctest comparison flags to match on. e.g.
+            doctest.ELLIPSIS.
+        """
+        if not example.endswith('\n'):
+            example += '\n'
+        self.want = example # required variable name by doctest.
+        self.flags = flags
+        self._checker = doctest.OutputChecker()
+
+    def __str__(self):
+        if self.flags:
+            flagstr = ", flags=%d" % self.flags
+        else:
+            flagstr = ""
+        return 'DocTestMatches(%r%s)' % (self.want, flagstr)
+
+    def _with_nl(self, actual):
+        result = str(actual)
+        if not result.endswith('\n'):
+            result += '\n'
+        return result
+
+    def match(self, actual):
+        with_nl = self._with_nl(actual)
+        if self._checker.check_output(self.want, with_nl, self.flags):
+            return None
+        return DocTestMismatch(self, with_nl)
+
+    def _describe_difference(self, with_nl):
+        return self._checker.output_difference(self, with_nl, self.flags)
+
+
+class DocTestMismatch:
+    """Mismatch object for DocTestMatches."""
+
+    def __init__(self, matcher, with_nl):
+        self.matcher = matcher
+        self.with_nl = with_nl
+
+    def describe(self):
+        return self.matcher._describe_difference(self.with_nl)
+
+
+class Equals:
+    """Matches if the items are equal."""
+
+    def __init__(self, expected):
+        self.expected = expected
+
+    def match(self, other):
+        if self.expected == other:
+            return None
+        return EqualsMismatch(self.expected, other)
+
+    def __str__(self):
+        return "Equals(%r)" % self.expected
+
+
+class EqualsMismatch:
+    """Two things differed."""
+
+    def __init__(self, expected, other):
+        self.expected = expected
+        self.other = other
+
+    def describe(self):
+        return "%r != %r" % (self.expected, self.other)
+
+
+class MatchesAny:
+    """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 MismatchesAll:
+    """A mismatch with many child mismatches."""
+
+    def __init__(self, mismatches):
+        self.mismatches = mismatches
+
+    def describe(self):
+        descriptions = ["Differences: ["]
+        for mismatch in self.mismatches:
+            descriptions.append(mismatch.describe())
+        descriptions.append("]\n")
+        return '\n'.join(descriptions)