return the undefined the option

binding/lua_c/bench_test.lua

@@ -40,6 +40,9 @@ for _, r in ipairs(arg) do
             srcFile = v
         elseif k == "cache-policy" then
             cachePolicy = v
+        else
+            print(string.format("undefined option `%s`", r))
+            return
         end
 
         -- break the match iterate

binding/lua_c/search_test.lua

@@ -37,6 +37,9 @@ for _, r in ipairs(arg) do
             dbFile = v
         elseif k == "cache-policy" then
             cachePolicy = v
+        else
+            print(string.format("undefined option `%s`", r))
+            return
         end
 
         -- break the match iterate