diff --git a/Makefile b/Makefile
index d2bace8a5c..9132025e03 100644
--- a/Makefile
+++ b/Makefile
@@ -100,6 +100,7 @@ fmt:
 	-ignore "operator/config/gke-addon/image_configmap.yaml" \
 	-ignore "operator/config/rbac/cnrm_viewer_role.yaml" \
 	-ignore "operator/vendor/**" \
+	-ignore "**/testdata/**/_*" \
 	./
 
 .PHONY: lint