Added abc.abstractmethod decorator to BaseAuthentication.authenticate and fixed tests for the same.

rest_framework/authentication.py

@@ -36,6 +36,7 @@ class BaseAuthentication(abc.ABC):
     All authentication classes should extend BaseAuthentication.
     """
 
+    @abc.abstractmethod
     def authenticate(self, request):
         """
         Authenticate the request and return a two-tuple of (user, token).

tests/authentication/test_authentication.py

@@ -537,7 +537,7 @@ class NoAuthenticationClassesTests(TestCase):
 class BasicAuthenticationUnitTests(TestCase):
 
     def test_base_authentication_abstract_method(self):
-        with pytest.raises(NotImplementedError):
+        with pytest.raises(TypeError):
             BaseAuthentication().authenticate({})
 
     def test_basic_authentication_raises_error_if_user_not_found(self):