diff --git a/git_review/tests/utils.py b/git_review/tests/utils.py
index edd9deb9..56e743fb 100644
--- a/git_review/tests/utils.py
+++ b/git_review/tests/utils.py
@@ -38,11 +38,11 @@ GERRIT_CONF_TMPL = """
 
 def run_cmd(*args, **kwargs):
     """Run command and check the return code."""
-    preexec_fn = None
-
     if 'chdir' in kwargs:
         def preexec_fn():
             return os.chdir(kwargs['chdir'])
+    else:
+        preexec_fn = None
 
     try:
         proc = subprocess.Popen(args, stdin=subprocess.PIPE,