diff --git a/src/cephadm/tox.ini b/src/cephadm/tox.ini
index 2845124afd403..266520ff5727a 100644
--- a/src/cephadm/tox.ini
+++ b/src/cephadm/tox.ini
@@ -62,7 +62,7 @@ deps =
     flake8-quotes
 commands =
     flake8 --config=tox.ini {posargs:cephadm.py cephadmlib}
-    bash -c 'test $(git ls-files 'cephadm.py' 'cephadmlib/*.py' | xargs grep "docker.io" | wc -l) == 11'
+    bash -c 'test $(git ls-files 'cephadm.py' 'cephadmlib/*.py' | sort -u | xargs grep "docker.io" | wc -l) == 11'
 # Downstream distributions may choose to alter this "docker.io" number,
 # to make sure no new references to docker.io are creeping in unnoticed.