paranoid regex change
diff --git a/backport.py b/backport.py
index baeef37..afe87d4 100644
--- a/backport.py
+++ b/backport.py
@@ -57,7 +57,7 @@
 
     for pattern, sub in (
         ('(a|b)/Lib/unittest/mock.py', r'\1/mock/mock.py'),
-        ('(a|b)/Lib/unittest/test/testmock/(.+)', r'\1/mock/tests/\2'),
+        (r'(a|b)/Lib/unittest/test/testmock/(\S+)', r'\1/mock/tests/\2'),
         ('(a|b)/Misc/NEWS', r'\1/NEWS'),
         ('(a|b)/NEWS.d/next/Library/(.+\.rst)', r'\1/NEWS.d/\2'),
     ):