test prefix stripping

main.go

@@ -38,6 +38,10 @@ func main() {
 		log.Fatal(err)
 	}
 
+	if c.Strip == "" {
+		c.Strip = "/"
+	}
+
 	frontendProxy := httputil.NewSingleHostReverseProxy(rpURL)
 
 	srv := &http.Server{