From 895cf695c440d7369255e92c9a0771b3bb0a0988 Mon Sep 17 00:00:00 2001
From: Simon Sapin <simon.sapin@exyr.org>
Date: Thu, 2 Jan 2020 16:44:17 +0100
Subject: [PATCH] Fix a Python 3 warning

```
/home/simon/projects/servo/python/servo/testing_commands.py:301:
SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if err is not 0:
```
---
 python/servo/testing_commands.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/python/servo/testing_commands.py b/python/servo/testing_commands.py
index c874d5ed26e..dad2af0aa04 100644
--- a/python/servo/testing_commands.py
+++ b/python/servo/testing_commands.py
@@ -298,7 +298,7 @@ class MachCommands(CommandBase):
                 args += ["--", "--nocapture"]
 
             err = self.run_cargo_build_like_command("bench" if bench else "test", args, env=env, **kwargs)
-            if err is not 0:
+            if err:
                 return err
 
     @Command('test-content',