Method handle

Lib/unittest/case.py:228–255

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.

(self, name, args, kwargs)

        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 not args:
                self.msg = kwargs.pop('msg', None)
                if kwargs:
                    raise TypeError('%r is an invalid keyword argument for '
                                    'this function' % (next(iter(kwargs)),))
                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):