'Setting subdir to `None` should raise an error.'

def test_empty_subdir2(self):

    self.auth.creds_subdir = None
    try:
        self.auth.load_creds()
    except ValueError:
        pass
    except Exception as e:
        self.fail(('Unexpected    exception    thrown:    %s' % e))
    else:
        self.fail('ValueError    exception    not    thrown.')
