httprouter

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/http/httptest"

	"github.com/goes-funky/httprouter"
)

type response struct {
	Message string `json:"message"`
}

func main() {
	router := httprouter.New()
	router.Handler(http.MethodGet, "/greet/:name", func(w http.ResponseWriter, req *http.Request) error {
		params := httprouter.GetParams(req.Context())

		response := response{Message: fmt.Sprintf("Hello %s!", params["name"])}
		return httprouter.JSONResponse(w, http.StatusOK, response)
	})

	server := httptest.NewServer(router)

	client := server.Client()

	httpResp, err := client.Get(server.URL + "/greet/fry")
	if err != nil {
		log.Fatal("failed to GET /greet/fry", err)
	}

	body, err := io.ReadAll(httpResp.Body)
	if err != nil {
		log.Fatal("failed to read http response body", err)
	}

	var resp response
	if err := json.Unmarshal(body, &resp); err != nil {
		log.Fatal("failed to unmarshal http response body", err)
	}

	if resp.Message != "Hello fry!" {
		log.Fatal("unexpected response")
	}
}

Output: