在编写的Django测试中，如何获得当前登录用户？

例如，这就是我想要写的测试：

def test_author_set_once(self):
    self.client.login(username='Adam', password='password')
    #create an object and test the author is adam
    self.client.login(username='Barry', password='password')
    #modify the first object and test that the author has not changed

所以我能这样

self.assertEqual(object.author, self.client.user)

(但我不能)

我现在的编码方式是这样的：

self.client.login(username='Adam', password='password')
self.user = User.objects.get(username='Adam')
#create an object 
self.assertEqual(object.author, self.user)