diff --git a/tests/lua53/strings.lua b/tests/lua53/strings.lua
index aaa0bf4..089feaf 100644
--- a/tests/lua53/strings.lua
+++ b/tests/lua53/strings.lua
@@ -236,6 +236,7 @@ end
 
 assert(string.format("\0%s\0", "\0\0\1") == "\0\0\0\1\0")
 checkerror("contains zeros", string.format, "%10s", "\0")
+checkerror("cannot have modifiers", string.format, "%10q", "1")
 
 -- format x tostring
 assert(string.format("%s %s", nil, true) == "nil true")