diff --git a/tests/xprop/test.py b/tests/xprop/test.py
index 94c52aecc..0d991ae00 100644
--- a/tests/xprop/test.py
+++ b/tests/xprop/test.py
@@ -453,7 +453,7 @@ for mode in ["", "_xprop"]:
             hierarchy -top top; proc -noopt
             flatten
             opt_expr -keepdc; clean
-            dump -o opt_expr{mode}.list */\Y_*
+            dump -readable -o opt_expr{mode}.list */\Y_*
         """
     )