diff --git a/single_file_tests/url.go b/single_file_tests/url.go
new file mode 100644
index 0000000..ada51d9
--- /dev/null
+++ b/single_file_tests/url.go
@@ -0,0 +1,18 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+	"net/url"
+)
+
+func main() {
+	q := url.Values{}
+	q.Add("b", "testing")
+	q.Add("a", "hello world")
+
+	// url.Values will sort keys(alphabet asc)
+	// and encode ' '(blank) to '+', SHOULD replace to '%20'
+	s := strings.ReplaceAll(q.Encode(), "+", "%20")
+	fmt.Println(s)
+}
\ No newline at end of file