text: """Test case implementation"""
  
  import sys
  import functools
  import difflib
  import logging
  import pprint
  import re
  import warnings
  import collections
  import contextlib
  import traceback
  
  from . import result
  from .util import (strclass, safe_repr, _count_diff_all_purpose,
                     _count_diff_hashable, _common_shorten_repr)
  
  __unittest = True
  
  _subtest_msg_sentinel = object()
  
  DIFF_OMITTED = ('\nDiff is %s characters long. '
                   'Set self.maxDiff to None to see it.')
  
  class SkipTest(Exception):
      """
      Raise this exception in a test to skip it.
  
      Usually you can use TestCase.skipTest() or one of the skipping decorators
      instead of raising this directly.
      """
  
  class _ShouldStop(Exception):
      """
      The test should stop.
      """
  
  class _UnexpectedSuccess(Exception):
      """
      The test was supposed to fail, but it didn't!
      """
  
  
  class _Outcome(object):
      def __init__(self, result=None):
          self.expecting_failure = False
          self.result = result
          self.result_supports_subtests = hasattr(result, "addSubTest")
          self.success = True
          self.skipped = []
          self.expectedFailure = None
          self.errors = []
  
      @contextlib.contextmanager
      def testPartExecutor(self, test_case, isTest=False):
          old_success = self.success
          self.success = True
          try:
              yield
          except KeyboardInterrupt:
              raise
          except SkipTest as e:
              self.success = False
              self.skipped.append((test_case, str(e)))
          except _ShouldStop:
              pass
          except:
              exc_info = sys.exc_info()
              if self.expecting_failure:
                  self.expectedFailure = exc_info
              else:
                  self.success = False
                  self.errors.append((test_case, exc_info))
              # explicitly break a reference cycle:
              # exc_info -> frame -> exc_info
              exc_info = None
          else:
              if self.result_supports_subtests and self.success:
                  self.errors.append((test_case, None))
          finally:
              self.success = self.success and old_success
  
  
  def _id(obj):
      return obj
  
  def skip(reason):
      """
      Unconditionally skip a test.
      """
      def decorator(test_item):
          if not isinstance(test_item, type):
              @functools.wraps(test_item)
              def skip_wrapper(*args, **kwargs):
                  raise SkipTest(reason)
              test_item = skip_wrapper
  
          test_item.__unittest_skip__ = True
          test_item.__unittest_skip_why__ = reason
          return test_item
      return decorator
  
  def skipIf(condition, reason):
      """
      Skip a test if the condition is true.
      """
      if condition:
          return skip(reason)
      return _id
  
  def skipUnless(condition, reason):
      """
      Skip a test unless the condition is true.
      """
      if not condition:
          return skip(reason)
      return _id
  
  def expectedFailure(test_item):
      test_item.__unittest_expecting_failure__ = True
      return test_item
  
  def _is_subtype(expected, basetype):
      if isinstance(expected, tuple):
          return all(_is_subtype(e, basetype) for e in expected)
      return isinstance(expected, type) and issubclass(expected, basetype)
  
  class _BaseTestCaseContext:
  
      def __init__(self, test_case):
          self.test_case = test_case
  
      def _raiseFailure(self, standardMsg):
          msg = self.test_case._formatMessage(self.msg, standardMsg)
          raise self.test_case.failureException(msg)
  
  class _AssertRaisesBaseContext(_BaseTestCaseContext):
  
      def __init__(self, expected, test_case, expected_regex=None):
          _BaseTestCaseContext.__init__(self, test_case)
          self.expected = expected
          self.test_case = test_case
          if expected_regex is not None:
              expected_regex = re.compile(expected_regex)
          self.expected_regex = expected_regex
          self.obj_name = None
          self.msg = None
  
      def handle(self, name, args, kwargs):
          """
          If args is empty, assertRaises/Warns is being used as a
          context manager, so check for a 'msg' kwarg and return self.
          If args is not empty, call a callable passing positional and keyword
          arguments.
          """
          try:
              if not _is_subtype(self.expected, self._base_type):
                  raise TypeError('%s() arg 1 must be %s' %
                                  (name, self._base_type_str))
              if args and args[0] is None:
                  warnings.warn("callable is None",
                                DeprecationWarning, 3)
                  args = ()
              if not args:
                  self.msg = kwargs.pop('msg', None)
                  if kwargs:
                      warnings.warn('%r is an invalid keyword argument for '
                                    'this function' % next(iter(kwargs)),
                                    DeprecationWarning, 3)
                  return self
  
              callable_obj, *args = args
              try:
                  self.obj_name = callable_obj.__name__
              except AttributeError:
                  self.obj_name = str(callable_obj)
              with self:
                  callable_obj(*args, **kwargs)
          finally:
              # bpo-23890: manually break a reference cycle
              self = None
  
  
  class _AssertRaisesContext(_AssertRaisesBaseContext):
      """A context manager used to implement TestCase.assertRaises* methods."""
  
      _base_type = BaseException
      _base_type_str = 'an exception type or tuple of exception types'
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_value, tb):
          if exc_type is None:
              try:
                  exc_name = self.expected.__name__
              except AttributeError:
                  exc_name = str(self.expected)
              if self.obj_name:
                  self._raiseFailure("{} not raised by {}".format(exc_name,
                                                                  self.obj_name))
              else:
                  self._raiseFailure("{} not raised".format(exc_name))
          else:
              traceback.clear_frames(tb)
          if not issubclass(exc_type, self.expected):
              # let unexpected exceptions pass through
              return False
          # store exception, without traceback, for later retrieval
          self.exception = exc_value.with_traceback(None)
          if self.expected_regex is None:
              return True
  
          expected_regex = self.expected_regex
          if not expected_regex.search(str(exc_value)):
              self._raiseFailure('"{}" does not match "{}"'.format(
                       expected_regex.pattern, str(exc_value)))
          return True
  
  
  class _AssertWarnsContext(_AssertRaisesBaseContext):
      """A context manager used to implement TestCase.assertWarns* methods."""
  
      _base_type = Warning
      _base_type_str = 'a warning type or tuple of warning types'
  
      def __enter__(self):
          # The __warningregistry__'s need to be in a pristine state for tests
          # to work properly.
          for v in sys.modules.values():
              if getattr(v, '__warningregistry__', None):
                  v.__warningregistry__ = {}
          self.warnings_manager = warnings.catch_warnings(record=True)
          self.warnings = self.warnings_manager.__enter__()
          warnings.simplefilter("always", self.expected)
          return self
  
      def __exit__(self, exc_type, exc_value, tb):
          self.warnings_manager.__exit__(exc_type, exc_value, tb)
          if exc_type is not None:
              # let unexpected exceptions pass through
              return
          try:
              exc_name = self.expected.__name__
          except AttributeError:
              exc_name = str(self.expected)
          first_matching = None
          for m in self.warnings:
              w = m.message
              if not isinstance(w, self.expected):
                  continue
              if first_matching is None:
                  first_matching = w
              if (self.expected_regex is not None and
                  not self.expected_regex.search(str(w))):
                  continue
              # store warning for later retrieval
              self.warning = w
              self.filename = m.filename
              self.lineno = m.lineno
              return
          # Now we simply try to choose a helpful failure message
          if first_matching is not None:
              self._raiseFailure('"{}" does not match "{}"'.format(
                       self.expected_regex.pattern, str(first_matching)))
          if self.obj_name:
              self._raiseFailure("{} not triggered by {}".format(exc_name,
                                                                 self.obj_name))
          else:
              self._raiseFailure("{} not triggered".format(exc_name))
  
  
  
  _LoggingWatcher = collections.namedtuple("_LoggingWatcher",
                                           ["records", "output"])
  
  
  class _CapturingHandler(logging.Handler):
      """
      A logging handler capturing all (raw and formatted) logging output.
      """
  
      def __init__(self):
          logging.Handler.__init__(self)
          self.watcher = _LoggingWatcher([], [])
  
      def flush(self):
          pass
  
      def emit(self, record):
          self.watcher.records.append(record)
          msg = self.format(record)
          self.watcher.output.append(msg)
  
  
  
  class _AssertLogsContext(_BaseTestCaseContext):
      """A context manager used to implement TestCase.assertLogs()."""
  
      LOGGING_FORMAT = "%(levelname)s:%(name)s:%(message)s"
  
      def __init__(self, test_case, logger_name, level):
          _BaseTestCaseContext.__init__(self, test_case)
          self.logger_name = logger_name
          if level:
              self.level = logging._nameToLevel.get(level, level)
          else:
              self.level = logging.INFO
          self.msg = None
  
      def __enter__(self):
          if isinstance(self.logger_name, logging.Logger):
              logger = self.logger = self.logger_name
          else:
              logger = self.logger = logging.getLogger(self.logger_name)
          formatter = logging.Formatter(self.LOGGING_FORMAT)
          handler = _CapturingHandler()
          handler.setFormatter(formatter)
          self.watcher = handler.watcher
          self.old_handlers = logger.handlers[:]
          self.old_level = logger.level
          self.old_propagate = logger.propagate
          logger.handlers = [handler]
          logger.setLevel(self.level)
          logger.propagate = False
          return handler.watcher
  
      def __exit__(self, exc_type, exc_value, tb):
          self.logger.handlers = self.old_handlers
          self.logger.propagate = self.old_propagate
          self.logger.setLevel(self.old_level)
          if exc_type is not None:
              # let unexpected exceptions pass through
              return False
          if len(self.watcher.records) == 0:
              self._raiseFailure(
                  "no logs of level {} or higher triggered on {}"
                  .format(logging.getLevelName(self.level), self.logger.name))
  
  
  class _OrderedChainMap(collections.ChainMap):
      def __iter__(self):
          seen = set()
          for mapping in self.maps:
              for k in mapping:
                  if k not in seen:
                      seen.add(k)
                      yield k
  
  
  class TestCase(object):
      """A class whose instances are single test cases.
  
      By default, the test code itself should be placed in a method named
      'runTest'.
  
      If the fixture may be used for many test cases, create as
      many test methods as are needed. When instantiating such a TestCase
      subclass, specify in the constructor arguments the name of the test method
      that the instance is to execute.
  
      Test authors should subclass TestCase for their own tests. Construction
      and deconstruction of the test's environment ('fixture') can be
      implemented by overriding the 'setUp' and 'tearDown' methods respectively.
  
      If it is necessary to override the __init__ method, the base class
      __init__ method must always be called. It is important that subclasses
      should not change the signature of their __init__ method, since instances
      of the classes are instantiated automatically by parts of the framework
      in order to be run.
  
      When subclassing TestCase, you can set these attributes:
      * failureException: determines which exception will be raised when
          the instance's assertion methods fail; test methods raising this
          exception will be deemed to have 'failed' rather than 'errored'.
      * longMessage: determines whether long messages (including repr of
          objects used in assert methods) will be printed on failure in *addition*
          to any explicit message passed.
      * maxDiff: sets the maximum length of a diff in failure messages
          by assert methods using difflib. It is looked up as an instance
          attribute so can be configured by individual tests if required.
      """
  
      failureException = AssertionError
  
      longMessage = True
  
      maxDiff = 80*8
  
      # If a string is longer than _diffThreshold, use normal comparison instead
      # of difflib.  See #11763.
      _diffThreshold = 2**16
  
      # Attribute used by TestSuite for classSetUp
  
      _classSetupFailed = False
  
      def __init__(self, methodName='runTest'):
          """Create an instance of the class that will use the named test
             method when executed. Raises a ValueError if the instance does
             not have a method with the specified name.
          """
          self._testMethodName = methodName
          self._outcome = None
          self._testMethodDoc = 'No test'
          try:
              testMethod = getattr(self, methodName)
          except AttributeError:
              if methodName != 'runTest':
                  # we allow instantiation with no explicit method name
                  # but not an *incorrect* or missing method name
                  raise ValueError("no such test method in %s: %s" %
                        (self.__class__, methodName))
          else:
              self._testMethodDoc = testMethod.__doc__
          self._cleanups = []
          self._subtest = None
  
          # Map types to custom assertEqual functions that will compare
          # instances of said type in more detail to generate a more useful
          # error message.
          self._type_equality_funcs = {}
          self.addTypeEqualityFunc(dict, 'assertDictEqual')
          self.addTypeEqualityFunc(list, 'assertListEqual')
          self.addTypeEqualityFunc(tuple, 'assertTupleEqual')
          self.addTypeEqualityFunc(set, 'assertSetEqual')
          self.addTypeEqualityFunc(frozenset, 'assertSetEqual')
          self.addTypeEqualityFunc(str, 'assertMultiLineEqual')
  
      def addTypeEqualityFunc(self, typeobj, function):
          """Add a type specific assertEqual style function to compare a type.
  
          This method is for use by TestCase subclasses that need to register
          their own type equality functions to provide nicer error messages.
  
          Args:
              typeobj: The data type to call this function on when both values
                      are of the same type in assertEqual().
              function: The callable taking two arguments and an optional
                      msg= argument that raises self.failureException with a
                      useful error message when the two arguments are not equal.
          """
          self._type_equality_funcs[typeobj] = function
  
      def addCleanup(*args, **kwargs):
          """Add a function, with arguments, to be called when the test is
          completed. Functions added are called on a LIFO basis and are
          called after tearDown on test failure or success.
  
          Cleanup items are called even if setUp fails (unlike tearDown)."""
          if len(args) >= 2:
              self, function, *args = args
          elif not args:
              raise TypeError("descriptor 'addCleanup' of 'TestCase' object "
                              "needs an argument")
          elif 'function' in kwargs:
              function = kwargs.pop('function')
              self, *args = args
          else:
              raise TypeError('addCleanup expected at least 1 positional '
                              'argument, got %d' % (len(args)-1))
          args = tuple(args)
  
          self._cleanups.append((function, args, kwargs))
  
      def setUp(self):
          "Hook method for setting up the test fixture before exercising it."
          pass
  
      def tearDown(self):
          "Hook method for deconstructing the test fixture after testing it."
          pass
  
      @classmethod
      def setUpClass(cls):
          "Hook method for setting up class fixture before running tests in the class."
  
      @classmethod
      def tearDownClass(cls):
          "Hook method for deconstructing the class fixture after running all tests in the class."
  
      def countTestCases(self):
          return 1
  
      def defaultTestResult(self):
          return result.TestResult()
  
      def shortDescription(self):
          """Returns a one-line description of the test, or None if no
          description has been provided.
  
          The default implementation of this method returns the first line of
          the specified test method's docstring.
          """
          doc = self._testMethodDoc
          return doc.strip().split("\n")[0].strip() if doc else None
  
  
      def id(self):
          return "%s.%s" % (strclass(self.__class__), self._testMethodName)
  
      def __eq__(self, other):
          if type(self) is not type(other):
              return NotImplemented
  
          return self._testMethodName == other._testMethodName
  
      def __hash__(self):
          return hash((type(self), self._testMethodName))
  
      def __str__(self):
          return "%s (%s)" % (self._testMethodName, strclass(self.__class__))
  
      def __repr__(self):
          return "<%s testMethod=%s>" % \
                 (strclass(self.__class__), self._testMethodName)
  
      def _addSkip(self, result, test_case, reason):
          addSkip = getattr(result, 'addSkip', None)
          if addSkip is not None:
              addSkip(test_case, reason)
          else:
              warnings.warn("TestResult has no addSkip method, skips not reported",
                            RuntimeWarning, 2)
              result.addSuccess(test_case)
  
      @contextlib.contextmanager
      def subTest(self, msg=_subtest_msg_sentinel, **params):
          """Return a context manager that will return the enclosed block
          of code in a subtest identified by the optional message and
          keyword parameters.  A failure in the subtest marks the test
          case as failed but resumes execution at the end of the enclosed
          block, allowing further test code to be executed.
          """
          if self._outcome is None or not self._outcome.result_supports_subtests:
              yield
              return
          parent = self._subtest
          if parent is None:
              params_map = _OrderedChainMap(params)
          else:
              params_map = parent.params.new_child(params)
          self._subtest = _SubTest(self, msg, params_map)
          try:
              with self._outcome.testPartExecutor(self._subtest, isTest=True):
                  yield
              if not self._outcome.success:
                  result = self._outcome.result
                  if result is not None and result.failfast:
                      raise _ShouldStop
              elif self._outcome.expectedFailure:
                  # If the test is expecting a failure, we really want to
                  # stop now and register the expected failure.
                  raise _ShouldStop
          finally:
              self._subtest = parent
  
      def _feedErrorsToResult(self, result, errors):
          for test, exc_info in errors:
              if isinstance(test, _SubTest):
                  result.addSubTest(test.test_case, test, exc_info)
              elif exc_info is not None:
                  if issubclass(exc_info[0], self.failureException):
                      result.addFailure(test, exc_info)
                  else:
                      result.addError(test, exc_info)
  
      def _addExpectedFailure(self, result, exc_info):
          try:
              addExpectedFailure = result.addExpectedFailure
          except AttributeError:
              warnings.warn("TestResult has no addExpectedFailure method, reporting as passes",
                            RuntimeWarning)
              result.addSuccess(self)
          else:
              addExpectedFailure(self, exc_info)
  
      def _addUnexpectedSuccess(self, result):
          try:
              addUnexpectedSuccess = result.addUnexpectedSuccess
          except AttributeError:
              warnings.warn("TestResult has no addUnexpectedSuccess method, reporting as failure",
                            RuntimeWarning)
              # We need to pass an actual exception and traceback to addFailure,
              # otherwise the legacy result can choke.
              try:
                  raise _UnexpectedSuccess from None
              except _UnexpectedSuccess:
                  result.addFailure(self, sys.exc_info())
          else:
              addUnexpectedSuccess(self)
  
      def run(self, result=None):
          orig_result = result
          if result is None:
              result = self.defaultTestResult()
              startTestRun = getattr(result, 'startTestRun', None)
              if startTestRun is not None:
                  startTestRun()
  
          result.startTest(self)
  
          testMethod = getattr(self, self._testMethodName)
          if (getattr(self.__class__, "__unittest_skip__", False) or
              getattr(testMethod, "__unittest_skip__", False)):
              # If the class or method was skipped.
              try:
                  skip_why = (getattr(self.__class__, '__unittest_skip_why__', '')
                              or getattr(testMethod, '__unittest_skip_why__', ''))
                  self._addSkip(result, self, skip_why)
              finally:
                  result.stopTest(self)
              return
          expecting_failure_method = getattr(testMethod,
                                             "__unittest_expecting_failure__", False)
          expecting_failure_class = getattr(self,
                                            "__unittest_expecting_failure__", False)
          expecting_failure = expecting_failure_class or expecting_failure_method
          outcome = _Outcome(result)
          try:
              self._outcome = outcome
  
              with outcome.testPartExecutor(self):
                  self.setUp()
              if outcome.success:
                  outcome.expecting_failure = expecting_failure
                  with outcome.testPartExecutor(self, isTest=True):
                      testMethod()
                  outcome.expecting_failure = False
                  with outcome.testPartExecutor(self):
                      self.tearDown()
  
              self.doCleanups()
              for test, reason in outcome.skipped:
                  self._addSkip(result, test, reason)
              self._feedErrorsToResult(result, outcome.errors)
              if outcome.success:
                  if expecting_failure:
                      if outcome.expectedFailure:
                          self._addExpectedFailure(result, outcome.expectedFailure)
                      else:
                          self._addUnexpectedSuccess(result)
                  else:
                      result.addSuccess(self)
              return result
          finally:
              result.stopTest(self)
              if orig_result is None:
                  stopTestRun = getattr(result, 'stopTestRun', None)
                  if stopTestRun is not None:
                      stopTestRun()
  
              # explicitly break reference cycles:
              # outcome.errors -> frame -> outcome -> outcome.errors
              # outcome.expectedFailure -> frame -> outcome -> outcome.expectedFailure
              outcome.errors.clear()
              outcome.expectedFailure = None
  
              # clear the outcome, no more needed
              self._outcome = None
  
      def doCleanups(self):
          """Execute all cleanup functions. Normally called for you after
          tearDown."""
          outcome = self._outcome or _Outcome()
          while self._cleanups:
              function, args, kwargs = self._cleanups.pop()
              with outcome.testPartExecutor(self):
                  function(*args, **kwargs)
  
          # return this for backwards compatibility
          # even though we no longer us it internally
          return outcome.success
  
      def __call__(self, *args, **kwds):
          return self.run(*args, **kwds)
  
      def debug(self):
          """Run the test without collecting errors in a TestResult"""
          self.setUp()
          getattr(self, self._testMethodName)()
          self.tearDown()
          while self._cleanups:
              function, args, kwargs = self._cleanups.pop(-1)
              function(*args, **kwargs)
  
      def skipTest(self, reason):
          """Skip this test."""
          raise SkipTest(reason)
  
      def fail(self, msg=None):
          """Fail immediately, with the given message."""
          raise self.failureException(msg)
  
      def assertFalse(self, expr, msg=None):
          """Check that the expression is false."""
          if expr:
              msg = self._formatMessage(msg, "%s is not false" % safe_repr(expr))
              raise self.failureException(msg)
  
      def assertTrue(self, expr, msg=None):
          """Check that the expression is true."""
          if not expr:
              msg = self._formatMessage(msg, "%s is not true" % safe_repr(expr))
              raise self.failureException(msg)
  
      def _formatMessage(self, msg, standardMsg):
          """Honour the longMessage attribute when generating failure messages.
          If longMessage is False this means:
          * Use only an explicit message if it is provided
          * Otherwise use the standard message for the assert
  
          If longMessage is True:
          * Use the standard message
          * If an explicit message is provided, plus ' : ' and the explicit message
          """
          if not self.longMessage:
              return msg or standardMsg
          if msg is None:
              return standardMsg
          try:
              # don't switch to '{}' formatting in Python 2.X
              # it changes the way unicode input is handled
              return '%s : %s' % (standardMsg, msg)
          except UnicodeDecodeError:
              return  '%s : %s' % (safe_repr(standardMsg), safe_repr(msg))
  
      def assertRaises(self, expected_exception, *args, **kwargs):
          """Fail unless an exception of class expected_exception is raised
             by the callable when invoked with specified positional and
             keyword arguments. If a different type of exception is
             raised, it will not be caught, and the test case will be
             deemed to have suffered an error, exactly as for an
             unexpected exception.
  
             If called with the callable and arguments omitted, will return a
             context object used like this::
  
                  with self.assertRaises(SomeException):
                      do_something()
  
             An optional keyword argument 'msg' can be provided when assertRaises
             is used as a context object.
  
             The context manager keeps a reference to the exception as
             the 'exception' attribute. This allows you to inspect the
             exception after the assertion::
  
                 with self.assertRaises(SomeException) as cm:
                     do_something()
                 the_exception = cm.exception
                 self.assertEqual(the_exception.error_code, 3)
          """
          context = _AssertRaisesContext(expected_exception, self)
          try:
              return context.handle('assertRaises', args, kwargs)
          finally:
              # bpo-23890: manually break a reference cycle
              context = None
  
      def assertWarns(self, expected_warning, *args, **kwargs):
          """Fail unless a warning of class warnClass is triggered
             by the callable when invoked with specified positional and
             keyword arguments.  If a different type of warning is
             triggered, it will not be handled: depending on the other
             warning filtering rules in effect, it might be silenced, printed
             out, or raised as an exception.
  
             If called with the callable and arguments omitted, will return a
             context object used like this::
  
                  with self.assertWarns(SomeWarning):
                      do_something()
  
             An optional keyword argument 'msg' can be provided when assertWarns
             is used as a context object.
  
             The context manager keeps a reference to the first matching
             warning as the 'warning' attribute; similarly, the 'filename'
             and 'lineno' attributes give you information about the line
             of Python code from which the warning was triggered.
             This allows you to inspect the warning after the assertion::
  
                 with self.assertWarns(SomeWarning) as cm:
                     do_something()
                 the_warning = cm.warning
                 self.assertEqual(the_warning.some_attribute, 147)
          """
          context = _AssertWarnsContext(expected_warning, self)
          return context.handle('assertWarns', args, kwargs)
  
      def assertLogs(self, logger=None, level=None):
          """Fail unless a log message of level *level* or higher is emitted
          on *logger_name* or its children.  If omitted, *level* defaults to
          INFO and *logger* defaults to the root logger.
  
          This method must be used as a context manager, and will yield
          a recording object with two attributes: `output` and `records`.
          At the end of the context manager, the `output` attribute will
          be a list of the matching formatted log messages and the
          `records` attribute will be a list of the corresponding LogRecord
          objects.
  
          Example::
  
              with self.assertLogs('foo', level='INFO') as cm:
                  logging.getLogger('foo').info('first message')
                  logging.getLogger('foo.bar').error('second message')
              self.assertEqual(cm.output, ['INFO:foo:first message',
                                           'ERROR:foo.bar:second message'])
          """
          return _AssertLogsContext(self, logger, level)
  
      def _getAssertEqualityFunc(self, first, second):
          """Get a detailed comparison function for the types of the two args.
  
          Returns: A callable accepting (first, second, msg=None) that will
          raise a failure exception if first != second with a useful human
          readable error message for those types.
          """
          #
          # NOTE(gregory.p.smith): I considered isinstance(first, type(second))
          # and vice versa.  I opted for the conservative approach in case
          # subclasses are not intended to be compared in detail to their super
          # class instances using a type equality func.  This means testing
          # subtypes won't automagically use the detailed comparison.  Callers
          # should use their type specific assertSpamEqual method to compare
          # subclasses if the detailed comparison is desired and appropriate.
          # See the discussion in http://bugs.python.org/issue2578.
          #
          if type(first) is type(second):
              asserter = self._type_equality_funcs.get(type(first))
              if asserter is not None:
                  if isinstance(asserter, str):
                      asserter = getattr(self, asserter)
                  return asserter
  
          return self._baseAssertEqual
  
      def _baseAssertEqual(self, first, second, msg=None):
          """The default assertEqual implementation, not type specific."""
          if not first == second:
              standardMsg = '%s != %s' % _common_shorten_repr(first, second)
              msg = self._formatMessage(msg, standardMsg)
              raise self.failureException(msg)
  
      def assertEqual(self, first, second, msg=None):
          """Fail if the two objects are unequal as determined by the '=='
             operator.
          """
          assertion_func = self._getAssertEqualityFunc(first, second)
          assertion_func(first, second, msg=msg)
  
      def assertNotEqual(self, first, second, msg=None):
          """Fail if the two objects are equal as determined by the '!='
             operator.
          """
          if not first != second:
              msg = self._formatMessage(msg, '%s == %s' % (safe_repr(first),
                                                            safe_repr(second)))
              raise self.failureException(msg)
  
      def assertAlmostEqual(self, first, second, places=None, msg=None,
                            delta=None):
          """Fail if the two objects are unequal as determined by their
             difference rounded to the given number of decimal places
             (default 7) and comparing to zero, or by comparing that the
             difference between the two objects is more than the given
             delta.
  
             Note that decimal places (from zero) are usually not the same
             as significant digits (measured from the most significant digit).
  
             If the two objects compare equal then they will automatically
             compare almost equal.
          """
          if first == second:
              # shortcut
              return
          if delta is not None and places is not None:
              raise TypeError("specify delta or places not both")
  
          diff = abs(first - second)
          if delta is not None:
              if diff <= delta:
                  return
  
              standardMsg = '%s != %s within %s delta (%s difference)' % (
                  safe_repr(first),
                  safe_repr(second),
                  safe_repr(delta),
                  safe_repr(diff))
          else:
              if places is None:
                  places = 7
  
              if round(diff, places) == 0:
                  return
  
              standardMsg = '%s != %s within %r places (%s difference)' % (
                  safe_repr(first),
                  safe_repr(second),
                  places,
                  safe_repr(diff))
          msg = self._formatMessage(msg, standardMsg)
          raise self.failureException(msg)
  
      def assertNotAlmostEqual(self, first, second, places=None, msg=None,
                               delta=None):
          """Fail if the two objects are equal as determined by their
             difference rounded to the given number of decimal places
             (default 7) and comparing to zero, or by comparing that the
             difference between the two objects is less than the given delta.
  
             Note that decimal places (from zero) are usually not the same
             as significant digits (measured from the most significant digit).
  
             Objects that are equal automatically fail.
          """
          if delta is not None and places is not None:
              raise TypeError("specify delta or places not both")
          diff = abs(first - second)
          if delta is not None:
              if not (first == second) and diff > delta:
                  return
              standardMsg = '%s == %s within %s delta (%s difference)' % (
                  safe_repr(first),
                  safe_repr(second),
                  safe_repr(delta),
                  safe_repr(diff))
          else:
              if places is None:
                  places = 7
              if not (first == second) and round(diff, places) != 0:
                  return
              standardMsg = '%s == %s within %r places' % (safe_repr(first),
                                                           safe_repr(second),
                                                           places)
  
          msg = self._formatMessage(msg, standardMsg)
          raise self.failureException(msg)
  
      def assertSequenceEqual(self, seq1, seq2, msg=None, seq_type=None):
          """An equality assertion for ordered sequences (like lists and tuples).
  
          For the purposes of this function, a valid ordered sequence type is one
          which can be indexed, has a length, and has an equality operator.
  
          Args:
              seq1: The first sequence to compare.
              seq2: The second sequence to compare.
              seq_type: The expected datatype of the sequences, or None if no
                      datatype should be enforced.
              msg: Optional message to use on failure instead of a list of
                      differences.
          """
          if seq_type is not None:
              seq_type_name = seq_type.__name__
              if not isinstance(seq1, seq_type):
                  raise self.failureException('First sequence is not a %s: %s'
                                          % (seq_type_name, safe_repr(seq1)))
              if not isinstance(seq2, seq_type):
                  raise self.failureException('Second sequence is not a %s: %s'
                                          % (seq_type_name, safe_repr(seq2)))
          else:
              seq_type_name = "sequence"
  
          differing = None
          try:
              len1 = len(seq1)
          except (TypeError, NotImplementedError):
              differing = 'First %s has no length.    Non-sequence?' % (
                      seq_type_name)
  
          if differing is None:
              try:
                  len2 = len(seq2)
              except (TypeError, NotImplementedError):
                  differing = 'Second %s has no length.    Non-sequence?' % (
                          seq_type_name)
  
          if differing is None:
              if seq1 == seq2:
                  return
  
              differing = '%ss differ: %s != %s\n' % (
                      (seq_type_name.capitalize(),) +
                      _common_shorten_repr(seq1, seq2))
  
              for i in range(min(len1, len2)):
                  try:
                      item1 = seq1[i]
                  except (TypeError, IndexError, NotImplementedError):
                      differing += ('\nUnable to index element %d of first %s\n' %
                                   (i, seq_type_name))
                      break
  
                  try:
                      item2 = seq2[i]
                  except (TypeError, IndexError, NotImplementedError):
                      differing += ('\nUnable to index element %d of second %s\n' %
                                   (i, seq_type_name))
                      break
  
                  if item1 != item2:
                      differing += ('\nFirst differing element %d:\n%s\n%s\n' %
                                   ((i,) + _common_shorten_repr(item1, item2)))
                      break
              else:
                  if (len1 == len2 and seq_type is None and
                      type(seq1) != type(seq2)):
                      # The sequences are the same, but have differing types.
                      return
  
              if len1 > len2:
                  differing += ('\nFirst %s contains %d additional '
                               'elements.\n' % (seq_type_name, len1 - len2))
                  try:
                      differing += ('First extra element %d:\n%s\n' %
                                    (len2, safe_repr(seq1[len2])))
                  except (TypeError, IndexError, NotImplementedError):
                      differing += ('Unable to index element %d '
                                    'of first %s\n' % (len2, seq_type_name))
              elif len1 < len2:
                  differing += ('\nSecond %s contains %d additional '
                               'elements.\n' % (seq_type_name, len2 - len1))
                  try:
                      differing += ('First extra element %d:\n%s\n' %
                                    (len1, safe_repr(seq2[len1])))
                  except (TypeError, IndexError, NotImplementedError):
                      differing += ('Unable to index element %d '
                                    'of second %s\n' % (len1, seq_type_name))
          standardMsg = differing
          diffMsg = '\n' + '\n'.join(
              difflib.ndiff(pprint.pformat(seq1).splitlines(),
                            pprint.pformat(seq2).splitlines()))
  
          standardMsg = self._truncateMessage(standardMsg, diffMsg)
          msg = self._formatMessage(msg, standardMsg)
          self.fail(msg)
  
      def _truncateMessage(self, message, diff):
          max_diff = self.maxDiff
          if max_diff is None or len(diff) <= max_diff:
              return message + diff
          return message + (DIFF_OMITTED % len(diff))
  
      def assertListEqual(self, list1, list2, msg=None):
          """A list-specific equality assertion.
  
          Args:
              list1: The first list to compare.
              list2: The second list to compare.
              msg: Optional message to use on failure instead of a list of
                      differences.
  
          """
          self.assertSequenceEqual(list1, list2, msg, seq_type=list)
  
      def assertTupleEqual(self, tuple1, tuple2, msg=None):
          """A tuple-specific equality assertion.
  
          Args:
              tuple1: The first tuple to compare.
              tuple2: The second tuple to compare.
              msg: Optional message to use on failure instead of a list of
                      differences.
          """
          self.assertSequenceEqual(tuple1, tuple2, msg, seq_type=tuple)
  
      def assertSetEqual(self, set1, set2, msg=None):
          """A set-specific equality assertion.
  
          Args:
              set1: The first set to compare.
              set2: The second set to compare.
              msg: Optional message to use on failure instead of a list of
                      differences.
  
          assertSetEqual uses ducktyping to support different types of sets, and
          is optimized for sets specifically (parameters must support a
          difference method).
          """
          try:
              difference1 = set1.difference(set2)
          except TypeError as e:
              self.fail('invalid type when attempting set difference: %s' % e)
          except AttributeError as e:
              self.fail('first argument does not support set difference: %s' % e)
  
          try:
              difference2 = set2.difference(set1)
          except TypeError as e:
              self.fail('invalid type when attempting set difference: %s' % e)
          except AttributeError as e:
              self.fail('second argument does not support set difference: %s' % e)
  
          if not (difference1 or difference2):
              return
  
          lines = []
          if difference1:
              lines.append('Items in the first set but not the second:')
              for item in difference1:
                  lines.append(repr(item))
          if difference2:
              lines.append('Items in the second set but not the first:')
              for item in difference2:
                  lines.append(repr(item))
  
          standardMsg = '\n'.join(lines)
          self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIn(self, member, container, msg=None):
          """Just like self.assertTrue(a in b), but with a nicer default message."""
          if member not in container:
              standardMsg = '%s not found in %s' % (safe_repr(member),
                                                    safe_repr(container))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertNotIn(self, member, container, msg=None):
          """Just like self.assertTrue(a not in b), but with a nicer default message."""
          if member in container:
              standardMsg = '%s unexpectedly found in %s' % (safe_repr(member),
                                                          safe_repr(container))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIs(self, expr1, expr2, msg=None):
          """Just like self.assertTrue(a is b), but with a nicer default message."""
          if expr1 is not expr2:
              standardMsg = '%s is not %s' % (safe_repr(expr1),
                                               safe_repr(expr2))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIsNot(self, expr1, expr2, msg=None):
          """Just like self.assertTrue(a is not b), but with a nicer default message."""
          if expr1 is expr2:
              standardMsg = 'unexpectedly identical: %s' % (safe_repr(expr1),)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertDictEqual(self, d1, d2, msg=None):
          self.assertIsInstance(d1, dict, 'First argument is not a dictionary')
          self.assertIsInstance(d2, dict, 'Second argument is not a dictionary')
  
          if d1 != d2:
              standardMsg = '%s != %s' % _common_shorten_repr(d1, d2)
              diff = ('\n' + '\n'.join(difflib.ndiff(
                             pprint.pformat(d1).splitlines(),
                             pprint.pformat(d2).splitlines())))
              standardMsg = self._truncateMessage(standardMsg, diff)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertDictContainsSubset(self, subset, dictionary, msg=None):
          """Checks whether dictionary is a superset of subset."""
          warnings.warn('assertDictContainsSubset is deprecated',
                        DeprecationWarning)
          missing = []
          mismatched = []
          for key, value in subset.items():
              if key not in dictionary:
                  missing.append(key)
              elif value != dictionary[key]:
                  mismatched.append('%s, expected: %s, actual: %s' %
                                    (safe_repr(key), safe_repr(value),
                                     safe_repr(dictionary[key])))
  
          if not (missing or mismatched):
              return
  
          standardMsg = ''
          if missing:
              standardMsg = 'Missing: %s' % ','.join(safe_repr(m) for m in
                                                      missing)
          if mismatched:
              if standardMsg:
                  standardMsg += '; '
              standardMsg += 'Mismatched values: %s' % ','.join(mismatched)
  
          self.fail(self._formatMessage(msg, standardMsg))
  
  
      def assertCountEqual(self, first, second, msg=None):
          """An unordered sequence comparison asserting that the same elements,
          regardless of order.  If the same element occurs more than once,
          it verifies that the elements occur the same number of times.
  
              self.assertEqual(Counter(list(first)),
                               Counter(list(second)))
  
           Example:
              - [0, 1, 1] and [1, 0, 1] compare equal.
              - [0, 0, 1] and [0, 1] compare unequal.
  
          """
          first_seq, second_seq = list(first), list(second)
          try:
              first = collections.Counter(first_seq)
              second = collections.Counter(second_seq)
          except TypeError:
              # Handle case with unhashable elements
              differences = _count_diff_all_purpose(first_seq, second_seq)
          else:
              if first == second:
                  return
              differences = _count_diff_hashable(first_seq, second_seq)
  
          if differences:
              standardMsg = 'Element counts were not equal:\n'
              lines = ['First has %d, Second has %d:  %r' % diff for diff in differences]
              diffMsg = '\n'.join(lines)
              standardMsg = self._truncateMessage(standardMsg, diffMsg)
              msg = self._formatMessage(msg, standardMsg)
              self.fail(msg)
  
      def assertMultiLineEqual(self, first, second, msg=None):
          """Assert that two multi-line strings are equal."""
          self.assertIsInstance(first, str, 'First argument is not a string')
          self.assertIsInstance(second, str, 'Second argument is not a string')
  
          if first != second:
              # don't use difflib if the strings are too long
              if (len(first) > self._diffThreshold or
                  len(second) > self._diffThreshold):
                  self._baseAssertEqual(first, second, msg)
              firstlines = first.splitlines(keepends=True)
              secondlines = second.splitlines(keepends=True)
              if len(firstlines) == 1 and first.strip('\r\n') == first:
                  firstlines = [first + '\n']
                  secondlines = [second + '\n']
              standardMsg = '%s != %s' % _common_shorten_repr(first, second)
              diff = '\n' + ''.join(difflib.ndiff(firstlines, secondlines))
              standardMsg = self._truncateMessage(standardMsg, diff)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertLess(self, a, b, msg=None):
          """Just like self.assertTrue(a < b), but with a nicer default message."""
          if not a < b:
              standardMsg = '%s not less than %s' % (safe_repr(a), safe_repr(b))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertLessEqual(self, a, b, msg=None):
          """Just like self.assertTrue(a <= b), but with a nicer default message."""
          if not a <= b:
              standardMsg = '%s not less than or equal to %s' % (safe_repr(a), safe_repr(b))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertGreater(self, a, b, msg=None):
          """Just like self.assertTrue(a > b), but with a nicer default message."""
          if not a > b:
              standardMsg = '%s not greater than %s' % (safe_repr(a), safe_repr(b))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertGreaterEqual(self, a, b, msg=None):
          """Just like self.assertTrue(a >= b), but with a nicer default message."""
          if not a >= b:
              standardMsg = '%s not greater than or equal to %s' % (safe_repr(a), safe_repr(b))
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIsNone(self, obj, msg=None):
          """Same as self.assertTrue(obj is None), with a nicer default message."""
          if obj is not None:
              standardMsg = '%s is not None' % (safe_repr(obj),)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIsNotNone(self, obj, msg=None):
          """Included for symmetry with assertIsNone."""
          if obj is None:
              standardMsg = 'unexpectedly None'
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertIsInstance(self, obj, cls, msg=None):
          """Same as self.assertTrue(isinstance(obj, cls)), with a nicer
          default message."""
          if not isinstance(obj, cls):
              standardMsg = '%s is not an instance of %r' % (safe_repr(obj), cls)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertNotIsInstance(self, obj, cls, msg=None):
          """Included for symmetry with assertIsInstance."""
          if isinstance(obj, cls):
              standardMsg = '%s is an instance of %r' % (safe_repr(obj), cls)
              self.fail(self._formatMessage(msg, standardMsg))
  
      def assertRaisesRegex(self, expected_exception, expected_regex,
                            *args, **kwargs):
          """Asserts that the message in a raised exception matches a regex.
  
          Args:
              expected_exception: Exception class expected to be raised.
              expected_regex: Regex (re.Pattern object or string) expected
                      to be found in error message.
              args: Function to be called and extra positional args.
              kwargs: Extra kwargs.
              msg: Optional message used in case of failure. Can only be used
                      when assertRaisesRegex is used as a context manager.
          """
          context = _AssertRaisesContext(expected_exception, self, expected_regex)
          return context.handle('assertRaisesRegex', args, kwargs)
  
      def assertWarnsRegex(self, expected_warning, expected_regex,
                           *args, **kwargs):
          """Asserts that the message in a triggered warning matches a regexp.
          Basic functioning is similar to assertWarns() with the addition
          that only warnings whose messages also match the regular expression
          are considered successful matches.
  
          Args:
              expected_warning: Warning class expected to be triggered.
              expected_regex: Regex (re.Pattern object or string) expected
                      to be found in error message.
              args: Function to be called and extra positional args.
              kwargs: Extra kwargs.
              msg: Optional message used in case of failure. Can only be used
                      when assertWarnsRegex is used as a context manager.
          """
          context = _AssertWarnsContext(expected_warning, self, expected_regex)
          return context.handle('assertWarnsRegex', args, kwargs)
  
      def assertRegex(self, text, expected_regex, msg=None):
          """Fail the test unless the text matches the regular expression."""
          if isinstance(expected_regex, (str, bytes)):
              assert expected_regex, "expected_regex must not be empty."
              expected_regex = re.compile(expected_regex)
          if not expected_regex.search(text):
              standardMsg = "Regex didn't match: %r not found in %r" % (
                  expected_regex.pattern, text)
              # _formatMessage ensures the longMessage option is respected
              msg = self._formatMessage(msg, standardMsg)
              raise self.failureException(msg)
  
      def assertNotRegex(self, text, unexpected_regex, msg=None):
          """Fail the test if the text matches the regular expression."""
          if isinstance(unexpected_regex, (str, bytes)):
              unexpected_regex = re.compile(unexpected_regex)
          match = unexpected_regex.search(text)
          if match:
              standardMsg = 'Regex matched: %r matches %r in %r' % (
                  text[match.start() : match.end()],
                  unexpected_regex.pattern,
                  text)
              # _formatMessage ensures the longMessage option is respected
              msg = self._formatMessage(msg, standardMsg)
              raise self.failureException(msg)
  
  
      def _deprecate(original_func):
          def deprecated_func(*args, **kwargs):
              warnings.warn(
                  'Please use {0} instead.'.format(original_func.__name__),
                  DeprecationWarning, 2)
              return original_func(*args, **kwargs)
          return deprecated_func
  
      # see #9424
      failUnlessEqual = assertEquals = _deprecate(assertEqual)
      failIfEqual = assertNotEquals = _deprecate(assertNotEqual)
      failUnlessAlmostEqual = assertAlmostEquals = _deprecate(assertAlmostEqual)
      failIfAlmostEqual = assertNotAlmostEquals = _deprecate(assertNotAlmostEqual)
      failUnless = assert_ = _deprecate(assertTrue)
      failUnlessRaises = _deprecate(assertRaises)
      failIf = _deprecate(assertFalse)
      assertRaisesRegexp = _deprecate(assertRaisesRegex)
      assertRegexpMatches = _deprecate(assertRegex)
      assertNotRegexpMatches = _deprecate(assertNotRegex)
  
  
  
  class FunctionTestCase(TestCase):
      """A test case that wraps a test function.
  
      This is useful for slipping pre-existing test functions into the
      unittest framework. Optionally, set-up and tidy-up functions can be
      supplied. As with TestCase, the tidy-up ('tearDown') function will
      always be called if the set-up ('setUp') function ran successfully.
      """
  
      def __init__(self, testFunc, setUp=None, tearDown=None, description=None):
          super(FunctionTestCase, self).__init__()
          self._setUpFunc = setUp
          self._tearDownFunc = tearDown
          self._testFunc = testFunc
          self._description = description
  
      def setUp(self):
          if self._setUpFunc is not None:
              self._setUpFunc()
  
      def tearDown(self):
          if self._tearDownFunc is not None:
              self._tearDownFunc()
  
      def runTest(self):
          self._testFunc()
  
      def id(self):
          return self._testFunc.__name__
  
      def __eq__(self, other):
          if not isinstance(other, self.__class__):
              return NotImplemented
  
          return self._setUpFunc == other._setUpFunc and \
                 self._tearDownFunc == other._tearDownFunc and \
                 self._testFunc == other._testFunc and \
                 self._description == other._description
  
      def __hash__(self):
          return hash((type(self), self._setUpFunc, self._tearDownFunc,
                       self._testFunc, self._description))
  
      def __str__(self):
          return "%s (%s)" % (strclass(self.__class__),
                              self._testFunc.__name__)
  
      def __repr__(self):
          return "<%s tec=%s>" % (strclass(self.__class__),
                                       self._testFunc)
  
      def shortDescription(self):
          if self._description is not None:
              return self._description
          doc = self._testFunc.__doc__
          return doc and doc.split("\n")[0].strip() or None
  
  
  class _SubTest(TestCase):
  
      def __init__(self, test_case, message, params):
          super().__init__()
          self._message = message
          self.test_case = test_case
          self.params = params
          self.failureException = test_case.failureException
  
      def runTest(self):
          raise NotImplementedError("subtests cannot be run directly")
  
      def _subDescription(self):
          parts = []
          if self._message is not _subtest_msg_sentinel:
              parts.append("[{}]".format(self._message))
          if self.params:
              params_desc = ', '.join(
                  "{}={!r}".format(k, v)
                  for (k, v) in self.params.items())
              parts.append("({})".format(params_desc))
          return " ".join(parts) or '(<subtest>)'
  
      def id(self):
          return "{} {}".format(self.test_case.id(), self._subDescription())
  
      def shortDescription(self):
          """Returns a one-line description of the subtest, or None if no
          description has been provided.
          """
          return self.test_case.shortDescription()
  
      def __str__(self):
          return "{} {}".format(self.test_case, self._subDescription())
  