diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index e196e32..6c093c9 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -23,7 +23,8 @@
   files = []
   for f in input_api.AffectedSourceFiles(input_api.FilterSourceFile):
     if (f.LocalPath().find('base/') != -1 and
-        f.LocalPath().find('base/test/') == -1):
+        f.LocalPath().find('base/test/') == -1 and
+        not f.LocalPath().endswith('_unittest.mm')):
       contents = input_api.ReadFile(f)
       if pattern.search(contents):
         files.append(f)