mock.py

# mock.py
# Test tools for mocking and patching.
# E-mail: fuzzyman AT voidspace DOT org DOT uk
#
# mock 1.0.1
# http://www.voidspace.org.uk/python/mock/
#
# Copyright (c) 2007-2013, Michael Foord & the mock team
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

__all__ = (
    'Mock',
    'MagicMock',
    'patch',
    'sentinel',
    'DEFAULT',
    'ANY',
    'call',
    'create_autospec',
    'FILTER_DIR',
    'NonCallableMock',
    'NonCallableMagicMock',
    'mock_open',
    'PropertyMock',
)


__version__ = '1.0.1'


import inspect
import pprint
import sys

from functools import wraps as original_wraps
if sys.version_info[:2] >= (3, 2):
    wraps = original_wraps
else:
    # Emulate 3.2+ functools.
    def wraps(func):
        def inner(f):
            f = original_wraps(func)(f)
            wrapped = getattr(func, '__wrapped__', func)
            f.__wrapped__ = wrapped
            return f
        return inner

# TODO: use six.
try:
    unicode
except NameError:
    # Python 3
    basestring = unicode = str

try:
    long
except NameError:
    # Python 3
    long = int

try:
    BaseException
except NameError:
    # Python 2.4 compatibility
    BaseException = Exception

try:
    next
except NameError:
    def next(obj):
        return obj.next()


BaseExceptions = (BaseException,)
if 'java' in sys.platform:
    # jython
    import java
    BaseExceptions = (BaseException, java.lang.Throwable)

try:
    _isidentifier = str.isidentifier
except AttributeError:
    # Python 2.X
    import keyword
    import re
    regex = re.compile(r'^[a-z_][a-z0-9_]*$', re.I)
    def _isidentifier(string):
        if string in keyword.kwlist:
            return False
        return regex.match(string)


inPy3k = sys.version_info[0] == 3

self = 'im_self'
builtin = '__builtin__'
if inPy3k:
    self = '__self__'
    builtin = 'builtins'

FILTER_DIR = True

# Workaround for Python issue #12370
# Without this, the __class__ properties wouldn't be set correctly
_safe_super = super

def _is_instance_mock(obj):
    # can't use isinstance on Mock objects because they override __class__
    # The base class for all mocks is NonCallableMock
    return issubclass(type(obj), NonCallableMock)


def _is_exception(obj):
    return (
        isinstance(obj, BaseExceptions) or
        isinstance(obj, ClassTypes) and issubclass(obj, BaseExceptions)
    )


class _slotted(object):
    __slots__ = ['a']


DescriptorTypes = (
    type(_slotted.a),
    property,
)


def _getsignature(func, skipfirst, instance=False):
    if isinstance(func, ClassTypes) and not instance:
        try:
            func = func.__init__
        except AttributeError:
            return
        skipfirst = True
    elif not isinstance(func, FunctionTypes):
        # for classes where instance is True we end up here too
        try:
            func = func.__call__
        except AttributeError:
            return

    if inPy3k:
        try:
            argspec = inspect.getfullargspec(func)
        except TypeError:
            # C function / method, possibly inherited object().__init__
            return
        regargs, varargs, varkw, defaults, kwonly, kwonlydef, ann = argspec
    else:
        try:
            regargs, varargs, varkwargs, defaults = inspect.getargspec(func)
        except TypeError:
            # C function / method, possibly inherited object().__init__
            return

    # instance methods and classmethods need to lose the self argument
    if getattr(func, self, None) is not None:
        regargs = regargs[1:]
    if skipfirst:
        # this condition and the above one are never both True - why?
        regargs = regargs[1:]

    if inPy3k:
        signature = inspect.formatargspec(
            regargs, varargs, varkw, defaults,
            kwonly, kwonlydef, ann, formatvalue=lambda value: "")
    else:
        signature = inspect.formatargspec(
            regargs, varargs, varkwargs, defaults,
            formatvalue=lambda value: "")
    return signature[1:-1], func


def _check_signature(func, mock, skipfirst, instance=False):
    if not _callable(func):
        return

    result = _getsignature(func, skipfirst, instance)
    if result is None:
        return
    signature, func = result

    # can't use self because "self" is common as an argument name
    # unfortunately even not in the first place
    src = "lambda _mock_self, %s: None" % signature
    checksig = eval(src, {})
    _copy_func_details(func, checksig)
    type(mock)._mock_check_sig = checksig


def _copy_func_details(func, funcopy):
    funcopy.__name__ = func.__name__
    funcopy.__doc__ = func.__doc__
    try:
        funcopy.__text_signature__ = func.__text_signature__
    except AttributeError:
        pass
    # we explicitly don't copy func.__dict__ into this copy as it would
    # expose original attributes that should be mocked
    try:
        funcopy.__module__ = func.__module__
    except AttributeError:
        pass
    try:
        funcopy.__defaults__ = func.__defaults__
    except AttributeError:
        pass
    try:
        funcopy.__kwdefaults__ = func.__kwdefaults__
    except AttributeError:
        pass
    if not inPy3k:
        funcopy.func_defaults = func.func_defaults
        return


def _callable(obj):
    if isinstance(obj, ClassTypes):
        return True
    if getattr(obj, '__call__', None) is not None:
        return True
    return False


def _is_list(obj):
    # checks for list or tuples
    # XXXX badly named!
    return type(obj) in (list, tuple)


def _instance_callable(obj):
    """Given an object, return True if the object is callable.
    For classes, return True if instances would be callable."""
    if not isinstance(obj, ClassTypes):
        # already an instance
        return getattr(obj, '__call__', None) is not None

    if inPy3k:
        # *could* be broken by a class overriding __mro__ or __dict__ via
        # a metaclass
        for base in (obj,) + obj.__mro__:
            if base.__dict__.get('__call__') is not None:
                return True
    else:
        klass = obj
        # uses __bases__ instead of __mro__ so that we work with old style classes
        if klass.__dict__.get('__call__') is not None:
            return True

        for base in klass.__bases__:
            if _instance_callable(base):
                return True
    return False


def _set_signature(mock, original, instance=False):
    # creates a function with signature (*args, **kwargs) that delegates to a
    # mock. It still does signature checking by calling a lambda with the same
    # signature as the original.
    if not _callable(original):
        return

    skipfirst = isinstance(original, ClassTypes)
    result = _getsignature(original, skipfirst, instance)
    if result is None:
        # was a C function (e.g. object().__init__ ) that can't be mocked
        return

    signature, func = result

    src = "lambda %s: None" % signature
    checksig = eval(src, {})
    _copy_func_details(func, checksig)

    name = original.__name__
    if not _isidentifier(name):
        name = 'funcopy'
    context = {'_checksig_': checksig, 'mock': mock}
    src = """def %s(*args, **kwargs):
    _checksig_(*args, **kwargs)
    return mock(*args, **kwargs)""" % name
    exec (src, context)
    funcopy = context[name]
    _setup_func(funcopy, mock)
    return funcopy


def _setup_func(funcopy, mock):
    funcopy.mock = mock

    # can't use isinstance with mocks
    if not _is_instance_mock(mock):
        return

    def assert_called_with(*args, **kwargs):
        return mock.assert_called_with(*args, **kwargs)
    def assert_called_once_with(*args, **kwargs):
        return mock.assert_called_once_with(*args, **kwargs)
    def assert_has_calls(*args, **kwargs):
        return mock.assert_has_calls(*args, **kwargs)
    def assert_any_call(*args, **kwargs):
        return mock.assert_any_call(*args, **kwargs)
    def reset_mock():
        funcopy.method_calls = _CallList()
        funcopy.mock_calls = _CallList()
        mock.reset_mock()
        ret = funcopy.return_value
        if _is_instance_mock(ret) and not ret is mock:
            ret.reset_mock()

    funcopy.called = False
    funcopy.call_count = 0
    funcopy.call_args = None
    funcopy.call_args_list = _CallList()
    funcopy.method_calls = _CallList()
    funcopy.mock_calls = _CallList()

    funcopy.return_value = mock.return_value
    funcopy.side_effect = mock.side_effect
    funcopy._mock_children = mock._mock_children

    funcopy.assert_called_with = assert_called_with
    funcopy.assert_called_once_with = assert_called_once_with
    funcopy.assert_has_calls = assert_has_calls
    funcopy.assert_any_call = assert_any_call
    funcopy.reset_mock = reset_mock

    mock._mock_delegate = funcopy


def _is_magic(name):
    return '__%s__' % name[2:-2] == name


class _SentinelObject(object):
    "A unique, named, sentinel object."
    def __init__(self, name):
        self.name = name

    def __repr__(self):
        return 'sentinel.%s' % self.name


class _Sentinel(object):
    """Access attributes to return a named object, usable as a sentinel."""
    def __init__(self):
        self._sentinels = {}

    def __getattr__(self, name):
        if name == '__bases__':
            # Without this help(unittest.mock) raises an exception
            raise AttributeError
        return self._sentinels.setdefault(name, _SentinelObject(name))


sentinel = _Sentinel()

DEFAULT = sentinel.DEFAULT
_missing = sentinel.MISSING
_deleted = sentinel.DELETED


class OldStyleClass:
    pass
ClassType = type(OldStyleClass)


def _copy(value):
    if type(value) in (dict, list, tuple, set):
        return type(value)(value)
    return value


ClassTypes = (type,)
if not inPy3k:
    ClassTypes = (type, ClassType)

_allowed_names = set(
    [
        'return_value', '_mock_return_value', 'side_effect',
        '_mock_side_effect', '_mock_parent', '_mock_new_parent',
        '_mock_name', '_mock_new_name'
    ]
)


def _delegating_property(name):
    _allowed_names.add(name)
    _the_name = '_mock_' + name
    def _get(self, name=name, _the_name=_the_name):
        sig = self._mock_delegate
        if sig is None:
            return getattr(self, _the_name)
        return getattr(sig, name)
    def _set(self, value, name=name, _the_name=_the_name):
        sig = self._mock_delegate
        if sig is None:
            self.__dict__[_the_name] = value
        else:
            setattr(sig, name, value)

    return property(_get, _set)



class _CallList(list):

    def __contains__(self, value):
        if not isinstance(value, list):
            return list.__contains__(self, value)
        len_value = len(value)
        len_self = len(self)
        if len_value > len_self:
            return False

        for i in range(0, len_self - len_value + 1):
            sub_list = self[i:i+len_value]
            if sub_list == value:
                return True
        return False

    def __repr__(self):
        return pprint.pformat(list(self))


def _check_and_set_parent(parent, value, name, new_name):
    if not _is_instance_mock(value):
        return False
    if ((value._mock_name or value._mock_new_name) or
        (value._mock_parent is not None) or
        (value._mock_new_parent is not None)):
        return False

    _parent = parent
    while _parent is not None:
        # setting a mock (value) as a child or return value of itself
        # should not modify the mock
        if _parent is value:
            return False
        _parent = _parent._mock_new_parent

    if new_name:
        value._mock_new_parent = parent
        value._mock_new_name = new_name
    if name:
        value._mock_parent = parent
        value._mock_name = name
    return True



class Base(object):
    _mock_return_value = DEFAULT
    _mock_side_effect = None
    def __init__(self, *args, **kwargs):
        pass



class NonCallableMock(Base):
    """A non-callable version of `Mock`"""

    def __new__(cls, *args, **kw):
        # every instance has its own class
        # so we can create magic methods on the
        # class without stomping on other mocks
        new = type(cls.__name__, (cls,), {'__doc__': cls.__doc__})
        instance = object.__new__(new)
        return instance


    def __init__(
            self, spec=None, wraps=None, name=None, spec_set=None,
            parent=None, _spec_state=None, _new_name='', _new_parent=None,
            **kwargs
        ):
        if _new_parent is None:
            _new_parent = parent

        __dict__ = self.__dict__
        __dict__['_mock_parent'] = parent
        __dict__['_mock_name'] = name
        __dict__['_mock_new_name'] = _new_name
        __dict__['_mock_new_parent'] = _new_parent

        if spec_set is not None:
            spec = spec_set
            spec_set = True

        self._mock_add_spec(spec, spec_set)

        __dict__['_mock_children'] = {}
        __dict__['_mock_wraps'] = wraps
        __dict__['_mock_delegate'] = None

        __dict__['_mock_called'] = False
        __dict__['_mock_call_args'] = None
        __dict__['_mock_call_count'] = 0
        __dict__['_mock_call_args_list'] = _CallList()
        __dict__['_mock_mock_calls'] = _CallList()

        __dict__['method_calls'] = _CallList()

        if kwargs:
            self.configure_mock(**kwargs)

        _safe_super(NonCallableMock, self).__init__(
            spec, wraps, name, spec_set, parent,
            _spec_state
        )


    def attach_mock(self, mock, attribute):
        """
        Attach a mock as an attribute of this one, replacing its name and
        parent. Calls to the attached mock will be recorded in the
        `method_calls` and `mock_calls` attributes of this one."""
        mock._mock_parent = None
        mock._mock_new_parent = None
        mock._mock_name = ''
        mock._mock_new_name = None

        setattr(self, attribute, mock)


    def mock_add_spec(self, spec, spec_set=False):
        """Add a spec to a mock. `spec` can either be an object or a
        list of strings. Only attributes on the `spec` can be fetched as
        attributes from the mock.

        If `spec_set` is True then only attributes on the spec can be set."""
        self._mock_add_spec(spec, spec_set)


    def _mock_add_spec(self, spec, spec_set):
        _spec_class = None

        if spec is not None and not _is_list(spec):
            if isinstance(spec, ClassTypes):
                _spec_class = spec
            else:
                _spec_class = _get_class(spec)

            spec = dir(spec)

        __dict__ = self.__dict__
        __dict__['_spec_class'] = _spec_class
        __dict__['_spec_set'] = spec_set
        __dict__['_mock_methods'] = spec


    def __get_return_value(self):
        ret = self._mock_return_value
        if self._mock_delegate is not None:
            ret = self._mock_delegate.return_value

        if ret is DEFAULT:
            ret = self._get_child_mock(
                _new_parent=self, _new_name='()'
            )
            self.return_value = ret
        return ret


    def __set_return_value(self, value):
        if self._mock_delegate is not None:
            self._mock_delegate.return_value = value
        else:
            self._mock_return_value = value
            _check_and_set_parent(self, value, None, '()')

    __return_value_doc = "The value to be returned when the mock is called."
    return_value = property(__get_return_value, __set_return_value,
                            __return_value_doc)


    @property
    def __class__(self):
        if self._spec_class is None:
            return type(self)
        return self._spec_class

    called = _delegating_property('called')
    call_count = _delegating_property('call_count')
    call_args = _delegating_property('call_args')
    call_args_list = _delegating_property('call_args_list')
    mock_calls = _delegating_property('mock_calls')


    def __get_side_effect(self):
        delegated = self._mock_delegate
        if delegated is None:
            return self._mock_side_effect
        return delegated.side_effect

    def __set_side_effect(self, value):
        value = _try_iter(value)
        delegated = self._mock_delegate
        if delegated is None:
            self._mock_side_effect = value
        else:
            delegated.side_effect = value

    side_effect = property(__get_side_effect, __set_side_effect)


    def reset_mock(self):
        "Restore the mock object to its initial state."
        self.called = False
        self.call_args = None
        self.call_count = 0
        self.mock_calls = _CallList()
        self.call_args_list = _CallList()
        self.method_calls = _CallList()

        for child in self._mock_children.values():
            if isinstance(child, _SpecState):
                continue
            child.reset_mock()

        ret = self._mock_return_value
        if _is_instance_mock(ret) and ret is not self:
            ret.reset_mock()


    def configure_mock(self, **kwargs):
        """Set attributes on the mock through keyword arguments.

        Attributes plus return values and side effects can be set on child
        mocks using standard dot notation and unpacking a dictionary in the
        method call:

        >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
        >>> mock.configure_mock(**attrs)"""
        for arg, val in sorted(kwargs.items(),
                               # we sort on the number of dots so that
                               # attributes are set before we set attributes on
                               # attributes
                               key=lambda entry: entry[0].count('.')):
            args = arg.split('.')
            final = args.pop()
            obj = self
            for entry in args:
                obj = getattr(obj, entry)
            setattr(obj, final, val)


    def __getattr__(self, name):
        if name == '_mock_methods':
            raise AttributeError(name)
        elif self._mock_methods is not None:
            if name not in self._mock_methods or name in _all_magics:
                raise AttributeError("Mock object has no attribute %r" % name)
        elif _is_magic(name):
            raise AttributeError(name)

        result = self._mock_children.get(name)
        if result is _deleted:
            raise AttributeError(name)
        elif result is None:
            wraps = None
            if self._mock_wraps is not None:
                # XXXX should we get the attribute without triggering code
                # execution?
                wraps = getattr(self._mock_wraps, name)

            result = self._get_child_mock(
                parent=self, name=name, wraps=wraps, _new_name=name,
                _new_parent=self
            )
            self._mock_children[name]  = result

        elif isinstance(result, _SpecState):
            result = create_autospec(
                result.spec, result.spec_set, result.instance,
                result.parent, result.name
            )
            self._mock_children[name]  = result

        return result


    def __repr__(self):
        _name_list = [self._mock_new_name]
        _parent = self._mock_new_parent
        last = self

        dot = '.'
        if _name_list == ['()']:
            dot = ''
        seen = set()
        while _parent is not None:
            last = _parent

            _name_list.append(_parent._mock_new_name + dot)
            dot = '.'
            if _parent._mock_new_name == '()':
                dot = ''

            _parent = _parent._mock_new_parent

            # use ids here so as not to call __hash__ on the mocks
            if id(_parent) in seen:
                break
            seen.add(id(_parent))

        _name_list = list(reversed(_name_list))
        _first = last._mock_name or 'mock'
        if len(_name_list) > 1:
            if _name_list[1] not in ('()', '().'):
                _first += '.'
        _name_list[0] = _first
        name = ''.join(_name_list)

        name_string = ''
        if name not in ('mock', 'mock.'):
            name_string = ' name=%r' % name

        spec_string = ''
        if self._spec_class is not None:
            spec_string = ' spec=%r'
            if self._spec_set:
                spec_string = ' spec_set=%r'
            spec_string = spec_string % self._spec_class.__name__
        return "<%s%s%s id='%s'>" % (
            type(self).__name__,
            name_string,
            spec_string,
            id(self)
        )


    def __dir__(self):
        """Filter the output of `dir(mock)` to only useful members."""
        if not FILTER_DIR and getattr(object, '__dir__', None):
            # object.__dir__ is not in 2.7
            return object.__dir__(self)

        extras = self._mock_methods or []
        from_type = dir(type(self))
        from_dict = list(self.__dict__)

        if FILTER_DIR:
            # object.__dir__ is not in 2.7
            from_type = [e for e in from_type if not e.startswith('_')]
            from_dict = [e for e in from_dict if not e.startswith('_') or
                         _is_magic(e)]
        return sorted(set(extras + from_type + from_dict +
                          list(self._mock_children)))


    def __setattr__(self, name, value):
        if name in _allowed_names:
            # property setters go through here
            return object.__setattr__(self, name, value)
        elif (self._spec_set and self._mock_methods is not None and
            name not in self._mock_methods and
            name not in self.__dict__):
            raise AttributeError("Mock object has no attribute '%s'" % name)
        elif name in _unsupported_magics:
            msg = 'Attempting to set unsupported magic method %r.' % name
            raise AttributeError(msg)
        elif name in _all_magics:
            if self._mock_methods is not None and name not in self._mock_methods:
                raise AttributeError("Mock object has no attribute '%s'" % name)

            if not _is_instance_mock(value):
                setattr(type(self), name, _get_method(name, value))
                original = value
                value = lambda *args, **kw: original(self, *args, **kw)
            else:
                # only set _new_name and not name so that mock_calls is tracked
                # but not method calls
                _check_and_set_parent(self, value, None, name)
                setattr(type(self), name, value)
                self._mock_children[name] = value
        elif name == '__class__':
            self._spec_class = value
            return
        else:
            if _check_and_set_parent(self, value, name, name):
                self._mock_children[name] = value
        return object.__setattr__(self, name, value)


    def __delattr__(self, name):
        if name in _all_magics and name in type(self).__dict__:
            delattr(type(self), name)
            if name not in self.__dict__:
                # for magic methods that are still MagicProxy objects and
                # not set on the instance itself
                return

        if name in self.__dict__:
            object.__delattr__(self, name)

        obj = self._mock_children.get(name, _missing)
        if obj is _deleted:
            raise AttributeError(name)
        if obj is not _missing:
            del self._mock_children[name]
        self._mock_children[name] = _deleted



    def _format_mock_call_signature(self, args, kwargs):
        name = self._mock_name or 'mock'
        return _format_call_signature(name, args, kwargs)


    def _format_mock_failure_message(self, args, kwargs):
        message = 'Expected call: %s\nActual call: %s'
        expected_string = self._format_mock_call_signature(args, kwargs)
        call_args = self.call_args
        if len(call_args) == 3:
            call_args = call_args[1:]
        actual_string = self._format_mock_call_signature(*call_args)
        return message % (expected_string, actual_string)


    def assert_called_with(_mock_self, *args, **kwargs):
        """assert that the mock was called with the specified arguments.

        Raises an AssertionError if the args and keyword args passed in are
        different to the last call to the mock."""
        self = _mock_self
        if self.call_args is None:
            expected = self._format_mock_call_signature(args, kwargs)
            raise AssertionError('Expected call: %s\nNot called' % (expected,))

        if self.call_args != (args, kwargs):
            msg = self._format_mock_failure_message(args, kwargs)
            raise AssertionError(msg)


    def assert_called_once_with(_mock_self, *args, **kwargs):
        """assert that the mock was called exactly once and with the specified
        arguments."""
        self = _mock_self
        if not self.call_count == 1:
            msg = ("Expected to be called once. Called %s times." %
                   self.call_count)
            raise AssertionError(msg)
        return self.assert_called_with(*args, **kwargs)


    def assert_has_calls(self, calls, any_order=False):
        """assert the mock has been called with the specified calls.
        The `mock_calls` list is checked for the calls.

        If `any_order` is False (the default) then the calls must be
        sequential. There can be extra calls before or after the
        specified calls.

        If `any_order` is True then the calls can be in any order, but
        they must all appear in `mock_calls`."""
        if not any_order:
            if calls not in self.mock_calls:
                raise AssertionError(
                    'Calls not found.\nExpected: %r\n'
                    'Actual: %r' % (calls, self.mock_calls)
                )
            return

        all_calls = list(self.mock_calls)

        not_found = []
        for kall in calls:
            try:
                all_calls.remove(kall)
            except ValueError:
                not_found.append(kall)
        if not_found:
            raise AssertionError(
                '%r not all found in call list' % (tuple(not_found),)
            )


    def assert_any_call(self, *args, **kwargs):
        """assert the mock has been called with the specified arguments.

        The assert passes if the mock has *ever* been called, unlike
        `assert_called_with` and `assert_called_once_with` that only pass if
        the call is the most recent one."""
        kall = call(*args, **kwargs)
        if kall not in self.call_args_list:
            expected_string = self._format_mock_call_signature(args, kwargs)
            raise AssertionError(
                '%s call not found' % expected_string
            )


    def _get_child_mock(self, **kw):
        """Create the child mocks for attributes and return value.
        By default child mocks will be the same type as the parent.
        Subclasses of Mock may want to override this to customize the way
        child mocks are made.

        For non-callable mocks the callable variant will be used (rather than
        any custom subclass)."""
        _type = type(self)
        if not issubclass(_type, CallableMixin):
            if issubclass(_type, NonCallableMagicMock):
                klass = MagicMock
            elif issubclass(_type, NonCallableMock) :
                klass = Mock
        else:
            klass = _type.__mro__[1]
        return klass(**kw)



def _try_iter(obj):
    if obj is None:
        return obj
    if _is_exception(obj):
        return obj
    if _callable(obj):
        return obj
    try:
        return iter(obj)
    except TypeError:
        # XXXX backwards compatibility
        # but this will blow up on first call - so maybe we should fail early?
        return obj



class CallableMixin(Base):

    def __init__(self, spec=None, side_effect=None, return_value=DEFAULT,
                 wraps=None, name=None, spec_set=None, parent=None,
                 _spec_state=None, _new_name='', _new_parent=None, **kwargs):
        self.__dict__['_mock_return_value'] = return_value

        _safe_super(CallableMixin, self).__init__(
            spec, wraps, name, spec_set, parent,
            _spec_state, _new_name, _new_parent, **kwargs
        )

        self.side_effect = side_effect


    def _mock_check_sig(self, *args, **kwargs):
        # stub method that can be replaced with one with a specific signature
        pass


    def __call__(_mock_self, *args, **kwargs):
        # can't use self in-case a function / method we are mocking uses self
        # in the signature
        _mock_self._mock_check_sig(*args, **kwargs)
        return _mock_self._mock_call(*args, **kwargs)


    def _mock_call(_mock_self, *args, **kwargs):
        self = _mock_self
        self.called = True
        self.call_count += 1
        self.call_args = _Call((args, kwargs), two=True)
        self.call_args_list.append(_Call((args, kwargs), two=True))

        _new_name = self._mock_new_name
        _new_parent = self._mock_new_parent
        self.mock_calls.append(_Call(('', args, kwargs)))

        seen = set()
        skip_next_dot = _new_name == '()'
        do_method_calls = self._mock_parent is not None
        name = self._mock_name
        while _new_parent is not None:
            this_mock_call = _Call((_new_name, args, kwargs))
            if _new_parent._mock_new_name:
                dot = '.'