Function _get_signature_object

Lib/unittest/mock.py:94–126

Given an arbitrary, possibly callable object, try to create a suitable signature object. Return a (reduced func, signature) tuple, or None.

(func, as_instance, eat_self)

def _get_signature_object(func, as_instance, eat_self):
    """
    Given an arbitrary, possibly callable object, try to create a suitable
    signature object.
    Return a (reduced func, signature) tuple, or None.
    """
    if isinstance(func, type) and not as_instance:
        # If it's a type and should be modelled as a type, use __init__.
        func = func.__init__
        # Skip the `self` argument in __init__
        eat_self = True
    elif isinstance(func, (classmethod, staticmethod)):
        if isinstance(func, classmethod):
            # Skip the `cls` argument of a class method
            eat_self = True
        # Use the original decorated method to extract the correct function signature
        func = func.__func__
    elif not isinstance(func, FunctionTypes):
        # If we really want to model an instance of the passed type,
        # __call__ should be looked up, not __init__.
        try:
            func = func.__call__
        except AttributeError:
            return None
    if eat_self:
        sig_func = partial(func, None)
    else:
        sig_func = func
    try:
        return func, inspect.signature(sig_func, annotation_format=Format.FORWARDREF)
    except ValueError:
        # Certain callable types are not supported by inspect.signature()
        return None


def _check_signature(func, mock, skipfirst, instance=False):