diff --git a/bitbake/lib/bb/tests/utils.py b/bitbake/lib/bb/tests/utils.py
index 4d5e21b99e..c363f62d7d 100644
--- a/bitbake/lib/bb/tests/utils.py
+++ b/bitbake/lib/bb/tests/utils.py
@@ -418,7 +418,7 @@ MULTILINE = "  stuff \\
                                ['MULTILINE'],
                                handle_var)
 
-        testvalue = re.sub('\s+', ' ', value_in_callback.strip())
+        testvalue = re.sub(r'\s+', ' ', value_in_callback.strip())
         self.assertEqual(expected_value, testvalue)
 
 class EditBbLayersConf(unittest.TestCase):