'Use in test cases to switch get/post operations to act as new user,
with self._different_user( "other_user@bx.psu.edu" ):
self._get( "histories" )  # Gets other_user@bx.psu.edu histories.'

@contextmanager
def _different_user(self, email=DEFAULT_OTHER_USER):

    original_api_key = self.user_api_key
    original_interactor_key = self.galaxy_interactor.api_key
    new_key = self._setup_user_get_key(email)
    try:
        self.user_api_key = new_key
        self.galaxy_interactor.api_key = new_key
        (yield)
    finally:
        self.user_api_key = original_api_key
        self.galaxy_interactor.api_key = original_interactor_key
