var _ = Service("calc", func() {
	Description("The calc service performs operations on numbers.")
	Method("add", func() {
		Payload(func() {
			Field(1, "a", Int, "Left operand")
			Field(2, "b", Int, "Right operand")
			Required("a", "b")
		})
		Result(Int)
		HTTP(func() {
			GET("/add/{a}/{b}")
			Response(StatusOK)
		})
	})

import (
...
	"calc/gen/calc"
	"calc/gen/http/calc/server"
)

func TestCalcsrvc_Add(t *testing.T) {
	checker := goahttpcheck.New()
	var logger log.Logger
	checker.Mount(server.NewAddHandler, server.MountAddHandler, calc.NewAddEndpoint(NewCalc(&logger)))

	// see. https://github.com/ikawaha/httpcheck
	checker.Test(t, http.MethodGet, "/add/1/2").
		Check().
		HasStatus(http.StatusOK).
		Cb(func(r *http.Response) {
			b, err := ioutil.ReadAll(r.Body)
			if err != nil {
				t.Fatalf("unexpected error, %v", err)
			}
			r.Body.Close()
			if got, expected := strings.TrimSpace(string(b)), "3"; got != expected {
				t.Errorf("got %+v, expected %v", b, expected)
			}
		})
}