in later/unittest/backport/mock.py [0:0]
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, type)
is_async_func = _is_async_func(spec)
_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 inspect.isdatadescriptor(spec):
# descriptors don't have a spec
# because we don't know what type they return
_kwargs = {}
elif is_async_func:
if instance:
raise RuntimeError("Instance can not be True when create_autospec "
"is mocking an async function")
Klass = AsyncMock
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)
if is_async_func:
_setup_async_mock(mock)
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
if asyncio.iscoroutinefunction(original):
child_klass = AsyncMock
else:
child_klass = MagicMock
new = child_klass(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