[1.7.x] Refs #21230 -- removed direct settings manipulation from signed cookies tests

import time

from django.conf import settings

from django.core import signing

from django.http import HttpRequest, HttpResponse

from django.test import TestCase

from django.test import TestCase, override_settings

class SignedCookieTest(TestCase):

        finally:

            time.time = _time

    @override_settings(SECRET_KEY=b'\xe7')

    def test_signed_cookies_with_binary_key(self):

        def restore_secret_key(prev):

            settings.SECRET_KEY = prev

        self.addCleanup(restore_secret_key, settings.SECRET_KEY)

        settings.SECRET_KEY = b'\xe7'

        response = HttpResponse()

        response.set_signed_cookie('c', 'hello')