Change Token.generate_key to a Classmethod (#7502)

* adds classmethod decorator to generate_key and test to confirm change is acceptable

* self -> cls

rest_framework/authtoken/models.py

@@ -32,7 +32,8 @@ class Token(models.Model):
             self.key = self.generate_key()
         return super().save(*args, **kwargs)
 
-    def generate_key(self):
+    @classmethod
+    def generate_key(cls):
         return binascii.hexlify(os.urandom(20)).decode()
 
     def __str__(self):

tests/authentication/test_authentication.py

@@ -397,6 +397,10 @@ class TokenAuthTests(BaseTokenAuthTests, TestCase):
         key = token.generate_key()
         assert isinstance(key, str)
 
+    def test_generate_key_accessible_as_classmethod(self):
+        key = self.model.generate_key()
+        assert isinstance(key, str)
+
     def test_token_login_json(self):
         """Ensure token login view using JSON POST works."""
         client = APIClient(enforce_csrf_checks=True)