mock.py

class MagicProxy(object):
    def __init__(self, name, parent):
        self.name = name
        self.parent = parent

    def __call__(self, *args, **kwargs):
        m = self.create_mock()
        return m(*args, **kwargs)

    def create_mock(self):
        entry = self.name
        parent = self.parent
        m = parent._get_child_mock(name=entry, _new_name=entry,
                                   _new_parent=parent)
        setattr(parent, entry, m)
        _set_return_value(parent, m, entry)
        return m

    def __get__(self, obj, _type=None):
        return self.create_mock()



class _ANY(object):
    "A helper object that compares equal to everything."

    def __eq__(self, other):
        return True

    def __ne__(self, other):
        return False

    def __repr__(self):
        return '<ANY>'

ANY = _ANY()



def _format_call_signature(name, args, kwargs):
    message = '%s(%%s)' % name
    formatted_args = ''
    args_string = ', '.join([repr(arg) for arg in args])
    kwargs_string = ', '.join([
        '%s=%r' % (key, value) for key, value in kwargs.items()
    ])
    if args_string:
        formatted_args = args_string
    if kwargs_string:
        if formatted_args:
            formatted_args += ', '
        formatted_args += kwargs_string

    return message % formatted_args



class _Call(tuple):
    """
    A tuple for holding the results of a call to a mock, either in the form
    `(args, kwargs)` or `(name, args, kwargs)`.

    If args or kwargs are empty then a call tuple will compare equal to
    a tuple without those values. This makes comparisons less verbose::

        _Call(('name', (), {})) == ('name',)
        _Call(('name', (1,), {})) == ('name', (1,))
        _Call(((), {'a': 'b'})) == ({'a': 'b'},)

    The `_Call` object provides a useful shortcut for comparing with call::

        _Call(((1, 2), {'a': 3})) == call(1, 2, a=3)
        _Call(('foo', (1, 2), {'a': 3})) == call.foo(1, 2, a=3)

    If the _Call has no name then it will match any name.
    """
    def __new__(cls, value=(), name=None, parent=None, two=False,
                from_kall=True):
        name = ''
        args = ()
        kwargs = {}
        _len = len(value)
        if _len == 3:
            name, args, kwargs = value
        elif _len == 2:
            first, second = value
            if isinstance(first, basestring):
                name = first
                if isinstance(second, tuple):
                    args = second
                else:
                    kwargs = second
            else:
                args, kwargs = first, second
        elif _len == 1:
            value, = value
            if isinstance(value, basestring):
                name = value
            elif isinstance(value, tuple):
                args = value
            else:
                kwargs = value

        if two:
            return tuple.__new__(cls, (args, kwargs))

        return tuple.__new__(cls, (name, args, kwargs))


    def __init__(self, value=(), name=None, parent=None, two=False,
                 from_kall=True):
        self.name = name
        self.parent = parent
        self.from_kall = from_kall


    def __eq__(self, other):
        if other is ANY:
            return True
        try:
            len_other = len(other)
        except TypeError:
            return False

        self_name = ''
        if len(self) == 2:
            self_args, self_kwargs = self
        else:
            self_name, self_args, self_kwargs = self

        other_name = ''
        if len_other == 0:
            other_args, other_kwargs = (), {}
        elif len_other == 3:
            other_name, other_args, other_kwargs = other
        elif len_other == 1:
            value, = other
            if isinstance(value, tuple):
                other_args = value
                other_kwargs = {}
            elif isinstance(value, basestring):
                other_name = value
                other_args, other_kwargs = (), {}
            else:
                other_args = ()
                other_kwargs = value
        else:
            # len 2
            # could be (name, args) or (name, kwargs) or (args, kwargs)
            first, second = other
            if isinstance(first, basestring):
                other_name = first
                if isinstance(second, tuple):
                    other_args, other_kwargs = second, {}
                else:
                    other_args, other_kwargs = (), second
            else:
                other_args, other_kwargs = first, second

        if self_name and other_name != self_name:
            return False

        # this order is important for ANY to work!
        return (other_args, other_kwargs) == (self_args, self_kwargs)


    def __ne__(self, other):
        return not self.__eq__(other)


    def __call__(self, *args, **kwargs):
        if self.name is None:
            return _Call(('', args, kwargs), name='()')

        name = self.name + '()'
        return _Call((self.name, args, kwargs), name=name, parent=self)


    def __getattr__(self, attr):
        if self.name is None:
            return _Call(name=attr, from_kall=False)
        name = '%s.%s' % (self.name, attr)
        return _Call(name=name, parent=self, from_kall=False)


    def __repr__(self):
        if not self.from_kall:
            name = self.name or 'call'
            if name.startswith('()'):
                name = 'call%s' % name
            return name

        if len(self) == 2:
            name = 'call'
            args, kwargs = self
        else:
            name, args, kwargs = self
            if not name:
                name = 'call'
            elif not name.startswith('()'):
                name = 'call.%s' % name
            else:
                name = 'call%s' % name
        return _format_call_signature(name, args, kwargs)


    def call_list(self):
        """For a call object that represents multiple calls, `call_list`
        returns a list of all the intermediate calls as well as the
        final call."""
        vals = []
        thing = self
        while thing is not None:
            if thing.from_kall:
                vals.append(thing)
            thing = thing.parent
        return _CallList(reversed(vals))


call = _Call(from_kall=False)



def create_autospec(spec, spec_set=False, instance=False, _parent=None,
                    _name=None, **kwargs):
    """Create a mock object using another object as a spec. Attributes on the
    mock will use the corresponding attribute on the `spec` object as their
    spec.

    Functions or methods being mocked will have their arguments checked
    to check that they are called with the correct signature.

    If `spec_set` is True then attempting to set attributes that don't exist
    on the spec object will raise an `AttributeError`.

    If a class is used as a spec then the return value of the mock (the
    instance of the class) will have the same spec. You can use a class as the
    spec for an instance object by passing `instance=True`. The returned mock
    will only be callable if instances of the mock are callable.

    `create_autospec` also takes arbitrary keyword arguments that are passed to
    the constructor of the created mock."""
    if _is_list(spec):
        # can't pass a list instance to the mock constructor as it will be
        # interpreted as a list of strings
        spec = type(spec)

    is_type = isinstance(spec, ClassTypes)

    _kwargs = {'spec': spec}
    if spec_set:
        _kwargs = {'spec_set': spec}
    elif spec is None:
        # None we mock with a normal mock without a spec
        _kwargs = {}
    if _kwargs and instance:
        _kwargs['_spec_as_instance'] = True

    _kwargs.update(kwargs)

    Klass = MagicMock
    if type(spec) in DescriptorTypes:
        # descriptors don't have a spec
        # because we don't know what type they return
        _kwargs = {}
    elif not _callable(spec):
        Klass = NonCallableMagicMock
    elif is_type and instance and not _instance_callable(spec):
        Klass = NonCallableMagicMock

    _name = _kwargs.pop('name', _name)

    _new_name = _name
    if _parent is None:
        # for a top level object no _new_name should be set
        _new_name = ''

    mock = Klass(parent=_parent, _new_parent=_parent, _new_name=_new_name,
                 name=_name, **_kwargs)

    if isinstance(spec, FunctionTypes):
        # should only happen at the top level because we don't
        # recurse for functions
        mock = _set_signature(mock, spec)
    else:
        _check_signature(spec, mock, is_type, instance)

    if _parent is not None and not instance:
        _parent._mock_children[_name] = mock

    if is_type and not instance and 'return_value' not in kwargs:
        mock.return_value = create_autospec(spec, spec_set, instance=True,
                                            _name='()', _parent=mock)

    for entry in dir(spec):
        if _is_magic(entry):
            # MagicMock already does the useful magic methods for us
            continue

        # XXXX do we need a better way of getting attributes without
        # triggering code execution (?) Probably not - we need the actual
        # object to mock it so we would rather trigger a property than mock
        # the property descriptor. Likewise we want to mock out dynamically
        # provided attributes.
        # XXXX what about attributes that raise exceptions other than
        # AttributeError on being fetched?
        # we could be resilient against it, or catch and propagate the
        # exception when the attribute is fetched from the mock
        try:
            original = getattr(spec, entry)
        except AttributeError:
            continue

        kwargs = {'spec': original}
        if spec_set:
            kwargs = {'spec_set': original}

        if not isinstance(original, FunctionTypes):
            new = _SpecState(original, spec_set, mock, entry, instance)
            mock._mock_children[entry] = new
        else:
            parent = mock
            if isinstance(spec, FunctionTypes):
                parent = mock.mock

            skipfirst = _must_skip(spec, entry, is_type)
            kwargs['_eat_self'] = skipfirst
            new = MagicMock(parent=parent, name=entry, _new_name=entry,
                            _new_parent=parent,
                            **kwargs)
            mock._mock_children[entry] = new
            _check_signature(original, new, skipfirst=skipfirst)

        # so functions created with _set_signature become instance attributes,
        # *plus* their underlying mock exists in _mock_children of the parent
        # mock. Adding to _mock_children may be unnecessary where we are also
        # setting as an instance attribute?
        if isinstance(new, FunctionTypes):
            setattr(mock, entry, new)

    return mock


def _must_skip(spec, entry, is_type):
    """
    Return whether we should skip the first argument on spec's `entry`
    attribute.
    """
    if not isinstance(spec, ClassTypes):
        if entry in getattr(spec, '__dict__', {}):
            # instance attribute - shouldn't skip
            return False
        spec = spec.__class__
    if not hasattr(spec, '__mro__'):
        # old style class: can't have descriptors anyway
        return is_type

    for klass in spec.__mro__:
        result = klass.__dict__.get(entry, DEFAULT)
        if result is DEFAULT:
            continue
        if isinstance(result, (staticmethod, classmethod)):
            return False
        elif isinstance(getattr(result, '__get__', None), MethodWrapperTypes):
            # Normal method => skip if looked up on type
            # (if looked up on instance, self is already skipped)
            return is_type
        else:
            return False

    # shouldn't get here unless function is a dynamically provided attribute
    # XXXX untested behaviour
    return is_type


def _get_class(obj):
    try:
        return obj.__class__
    except AttributeError:
        # it is possible for objects to have no __class__
        return type(obj)


class _SpecState(object):

    def __init__(self, spec, spec_set=False, parent=None,
                 name=None, ids=None, instance=False):
        self.spec = spec
        self.ids = ids
        self.spec_set = spec_set
        self.parent = parent
        self.instance = instance
        self.name = name


FunctionTypes = (
    # python function
    type(create_autospec),
    # instance method
    type(ANY.__eq__),
)

MethodWrapperTypes = (
    type(ANY.__eq__.__get__),
)


file_spec = None

def _iterate_read_data(read_data):
    # Helper for mock_open:
    # Retrieve lines from read_data via a generator so that separate calls to
    # readline, read, and readlines are properly interleaved
    data_as_list = ['{}\n'.format(l) for l in read_data.split('\n')]

    if data_as_list[-1] == '\n':
        # If the last line ended in a newline, the list comprehension will have an
        # extra entry that's just a newline.  Remove this.
        data_as_list = data_as_list[:-1]
    else:
        # If there wasn't an extra newline by itself, then the file being
        # emulated doesn't have a newline to end the last line  remove the
        # newline that our naive format() added
        data_as_list[-1] = data_as_list[-1][:-1]

    for line in data_as_list:
        yield line

def mock_open(mock=None, read_data=''):
    """
    A helper function to create a mock to replace the use of `open`. It works
    for `open` called directly or used as a context manager.

    The `mock` argument is the mock object to configure. If `None` (the
    default) then a `MagicMock` will be created for you, with the API limited
    to methods or attributes available on standard file handles.

    `read_data` is a string for the `read` methoddline`, and `readlines` of the
    file handle to return.  This is an empty string by default.
    """
    def _readlines_side_effect(*args, **kwargs):
        if handle.readlines.return_value is not None:
            return handle.readlines.return_value
        return list(_data)

    def _read_side_effect(*args, **kwargs):
        if handle.read.return_value is not None:
            return handle.read.return_value
        return ''.join(_data)

    def _readline_side_effect():
        if handle.readline.return_value is not None:
            while True:
                yield handle.readline.return_value
        for line in _data:
            yield line


    global file_spec
    if file_spec is None:
        # set on first use
        if inPy3k:
            import _io
            file_spec = list(set(dir(_io.TextIOWrapper)).union(set(dir(_io.BytesIO))))
        else:
            file_spec = file

    if mock is None:
        mock = MagicMock(name='open', spec=open)

    handle = MagicMock(spec=file_spec)
    handle.__enter__.return_value = handle

    _data = _iterate_read_data(read_data)

    handle.write.return_value = None
    handle.read.return_value = None
    handle.readline.return_value = None
    handle.readlines.return_value = None

    handle.read.side_effect = _read_side_effect
    handle.readline.side_effect = _readline_side_effect()
    handle.readlines.side_effect = _readlines_side_effect

    mock.return_value = handle
    return mock


class PropertyMock(Mock):
    """
    A mock intended to be used as a property, or other descriptor, on a class.
    `PropertyMock` provides `__get__` and `__set__` methods so you can specify
    a return value when it is fetched.

    Fetching a `PropertyMock` instance from an object calls the mock, with
    no args. Setting it calls the mock with the value being set.
    """
    def _get_child_mock(self, **kwargs):
        return MagicMock(**kwargs)

    def __get__(self, obj, obj_type):
        return self()
    def __set__(self, obj, val):
        self(val)