问为什么django.test.client.Client不让我保持登录状态

EN

class Test(TestCase):
    def test_view(self):
        user.set_password(password)
        user.save()

        client = self.client
        # I thought a more manual way would work, but no luck
        # client.post('/login', {'username':user.username, 'password':password})
        login_successful = client.login(username=user.username, password=password)
        # this assert passes  
        self.assertTrue(login_successful)

        response = client.get("/path", follow=True)
        #whether follow=True or not doesn't seem to work

        self.assertContains(response, "needle" )

{% if not request.user.is_authenticated %}
    ... form ...
{% endif %}