在Golang中测试HTTP客户端的指南

如果你的应用程序使用HTTP客户端来调用另一个服务，如果你希望在测试环境中不调用该服务，你可以使用下面的例子。它模拟了服务，所以你的HTTP客户端调用模拟服务。

客户端

package pkg

import "net/http"

type Consumer struct {
	ServiceAddress string
}

func (c Consumer) GetUsers() (*http.Response, error) {
	req, err := http.NewRequest(http.MethodGet, c.ServiceAddress + "/server/api/v1/users", nil)
	if err != nil {
		return nil, err
	}

	client := http.Client{}
	res, err := client.Do(req)
	if err != nil {
		return nil, err
	}

	return res, nil
}

测试

package pkg

import (
	"io/ioutil"
	"net/http"
	"net/http/httptest"
	"testing"
)

func TestConsumer_GetUsers(t *testing.T) {
	srv := serverMock()
	defer srv.Close()

	consumer := Consumer{ServiceAddress: srv.URL}

	res, err := consumer.GetUsers()
	if err !=  nil {
		t.Error(err)
	}

	body, err := ioutil.ReadAll(res.Body)
	if err !=  nil {
		t.Error(err)
	}
	res.Body.Close()

	if http.StatusOK != res.StatusCode  {
		t.Error("expected", http.StatusOK, "got", res.StatusCode)
	}
	if "mock server responding" != string(body) {
		t.Error("expected mock server responding got", string(body))
	}
}

func serverMock() *httptest.Server {
	handler := http.NewServeMux()
	handler.HandleFunc("/server/api/v1/users", usersMock)

	srv := httptest.NewServer(handler)

	return srv
}

func usersMock(w http.ResponseWriter, r *http.Request) {
	_, _ = w.Write([]byte("mock server responding"))
}