Ensure Token.generate_key returns a string.

rest_framework/authtoken/models.py

@@ -34,7 +34,7 @@ class Token(models.Model):
         return super(Token, self).save(*args, **kwargs)
 
     def generate_key(self):
-        return binascii.hexlify(os.urandom(20))
+        return binascii.hexlify(os.urandom(20)).decode()
 
     def __unicode__(self):
         return self.key

rest_framework/tests/test_authentication.py

@@ -195,6 +195,12 @@ class TokenAuthTests(TestCase):
         token = Token.objects.create(user=self.user)
         self.assertTrue(bool(token.key))
 
+    def test_generate_key_returns_string(self):
+        """Ensure generate_key returns a string"""
+        token = Token()
+        key = token.generate_key()
+        self.assertTrue(isinstance(key, str))
+
     def test_token_login_json(self):
         """Ensure token login view using JSON POST works."""
         client = APIClient(enforce_csrf_checks=True)