fix test for python 3.6

Author: florian-s-code

tests/test_client.py

@@ -1291,11 +1291,9 @@ def test_context_manager_exit_on_error(self):
         session = mock.Mock()
         session.get.return_value = response
 
-        with (
-            miniflux.Client("http://localhost", "username", "password", session=session) as client,
-            self.assertRaises(ServerError)
-        ):
-            client.get_version()
+        with miniflux.Client("http://localhost", "username", "password", session=session) as client:
+            with self.assertRaises(ServerError):
+                client.get_version()
 
         session.close.assert_called()