Correctly handle None

letsencrypt/client/client.py

@@ -381,7 +381,7 @@ def determine_authenticator(all_auths):
     else:
         raise errors.LetsEncryptClientError("No Authenticators available.")
 
-    if auth and auth in errs:
+    if auth is not None and auth in errs:
         logging.error("Please fix the configuration for the Authenticator. "
                       "The following error message was received: "
                       "%s", errs[auth])

letsencrypt/client/tests/client_test.py

@@ -59,7 +59,7 @@ class DetermineAuthenticatorTest(unittest.TestCase):
             errors.LetsEncryptMisconfigurationError)
         mock_choose.return_value = self.mock_apache
 
-        self.assertEqual(self._call(self.all_auths), None)
+        self.assertTrue(self._call(self.all_auths) is None)
 
 
 class RollbackTest(unittest.TestCase):

letsencrypt/client/tests/display/ops_test.py

@@ -51,7 +51,7 @@ class ChooseAuthenticatorTest(unittest.TestCase):
     def test_no_choice(self, mock_util):
         mock_util().menu.return_value = (display_util.CANCEL, 0)
 
-        self.assertEqual(self._call(self.auths, {}), None)
+        self.assertTrue(self._call(self.auths, {}) is None)
 
 
 class GenHttpsNamesTest(unittest.TestCase):