diff --git a/tests/docker/docker.py b/tests/docker/docker.py
index 688ef62..3b8a267 100755
--- a/tests/docker/docker.py
+++ b/tests/docker/docker.py
@@ -186,7 +186,7 @@ def _check_binfmt_misc(executable):
               (binary))
         return None, True
 
-    m = re.search("interpreter (\S+)\n", entry)
+    m = re.search(r"interpreter (\S+)\n", entry)
     interp = m.group(1)
     if interp and interp != executable:
         print("binfmt_misc for %s does not point to %s, using %s" %