diff --git a/src/test/res/strlib.lua b/src/test/res/strlib.lua
index 6cfb85be..5d4b929b 100644
--- a/src/test/res/strlib.lua
+++ b/src/test/res/strlib.lua
@@ -53,11 +53,11 @@ function t(str)
 	local i = { 0, 1, 2, 8, -1 }
 	for ki,vi in ipairs(i) do
 		local s,v = pcall( string.sub, str, vi )
-		print( 'string.sub("'..str..'",'..tostring(vi)..')='..tostring(s)..','..tostring(v) )
+		print( 'string.sub("'..str..'",'..tostring(vi)..')='..tostring(s)..',"'..tostring(v)..'"' )
 		local j = { 0, 1, 2, 4, 8, -1 }
 		for kj,vj in ipairs(j) do
 			local s,v = pcall( string.sub, str, vi, vj )
-			print( 'string.sub("'..str..'",'..tostring(vi)..','..tostring(vj)..')='..tostring(s)..','..tostring(v) )
+			print( 'string.sub("'..str..'",'..tostring(vi)..','..tostring(vj)..')='..tostring(s)..',"'..tostring(v)..'"' )
 		end
 	end
 end