Golang：使用httptest拦截和模拟HTTP响应

huangapple
go评论135阅读模式
英文:

Golang: Intercepting and Mocking an HTTP Response with httptest

问题

我已经研究了各种可以用于在golang中进行模拟测试的工具，但我正在尝试使用httptest来完成这个任务。特别是，我有一个如下所示的函数：

  1. type contact struct {
  2.   username string
  3.   number int
  4. }
  6. func getResponse(c contact) string {
  7.   url := fmt.Sprintf("https://mywebsite/%s", c.username)
  8.   req, err := http.NewRequest(http.MethodGet, url, nil)
  9.   // 错误检查
  11.   resp, err := http.DefaultClient.Do(req)
  12.   // 错误检查
  14.   return response
  15. }

我阅读的许多文档似乎要求创建一个客户端接口或自定义传输。在不更改主要代码的情况下，是否没有办法在测试文件中模拟响应？我希望将客户端、响应和所有相关细节都保留在getResponse函数中。我可能有错误的想法，但我正在尝试找到一种拦截http.DefaultClient.Do(req)调用并返回自定义响应的方法，这种方法可行吗？

英文:

I've looked into various different tools that can be used for mock testing in golang, but I'm trying to accomplish this task using httptest. In particular, I have a function as such:

  1. type contact struct {
  2.   username string
  3.   number int
  4. }
  6. func getResponse(c contact) string {
  7.   url := fmt.Sprintf("https://mywebsite/%s", c.username)
  8.   req, err := http.NewRequest(http.MethodGet, url, nil)
  9.   // error checking
  10.  
  11.   resp, err := http.DefaultClient.Do(req)
  12.   // error checking
  13.   
  14.   return response
  15. }
  16.

A lot of the documentation I've read seems to require creating a client interface or a custom transport. Is there no way to mock a response in a test file without changing this main code at all? I want to keep my client, response, and all the related details within the getResponse function. I could have the wrong idea, but I'm trying to find a way to intercept the http.DefaultClient.Do(req) call and return a custom response, is that possible?

答案1

得分: 1

我已经阅读了，似乎需要创建一个客户端接口，而不需要改变主要代码。

保持代码整洁是一个好的实践，你最终会习惯的，可测试的代码更加整洁，而整洁的代码更容易进行测试，所以不要担心改变你的代码（使用接口）以便接受模拟对象。

以下是你的代码的简单形式：

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"net/http"
  6. )
  8. type contact struct {
  9. 	username string
  10. 	number   int
  11. }
  13. type Client interface {
  14. 	Do(req *http.Request) (*http.Response, error)
  15. }
  17. func main() {
  18. 	getResponse(http.DefaultClient, contact{})
  19. }
  21. func getResponse(client Client, c contact) string {
  22.   url := fmt.Sprintf("https://mywebsite/%s", c.username)
  23.   req, _ := http.NewRequest(http.MethodGet, url, nil)
  24.   // 错误检查
  26.   resp, _ := http.DefaultClient.Do(req)
  27.   // 错误检查和响应处理
  29.   return response
  30. }

你的测试可以是这样的：

  1. package main
  3. import (
  4. 	"net/http"
  5. 	"testing"
  6. )
  8. type mockClient struct {
  9. }
  11. // Do 函数将使 mockClient 实现 Client 接口
  12. func (tc mockClient) Do(req *http.Request) (*http.Response, error) {
  13. 	return &http.Response{}, nil
  14. }
  16. func TestGetResponse(t *testing.T) {
  17. 	client := new(mockClient)
  18. 	getResponse(client, contact{})
  19. }

但是如果你更喜欢使用 httptest：

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"io"
  6. 	"net/http"
  7. 	"net/http/httptest"
  8. )
  10. type contact struct {
  11. 	username string
  12. 	number   int
  13. }
  15. func main() {
  16. 	fmt.Println(getResponse(contact{}))
  17. }
  19. func getResponse(c contact) string {
  20. 	// 创建一个测试服务器
  21. 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  22. 		fmt.Fprintln(w, "your response")
  23. 	}))
  25. 	defer ts.Close()
  27. 	// 你仍然需要设置你的基本 URL
  28. 	base_url := ts.URL
  30. 	url := fmt.Sprintf("%s/%s", base_url, c.username)
  31. 	req, _ := http.NewRequest(http.MethodGet, url, nil)
  33. 	// 在你的测试中使用 ts.Client() 而不是 http.DefaultClient。
  34. 	resp, _ := ts.Client().Do(req)
  36. 	// 处理响应
  37. 	response, _ := io.ReadAll(resp.Body)
  38. 	resp.Body.Close()
  40. 	return string(response)
  41. }
英文:

> I've read seems to require creating a client interface

> without changing this main code at all

Keeping your code clean is a good practice and you'll finally get used to it, a testable code is cleaner and a cleaner code is more testable, so don't worry to change your code (using interfaces) so it can accept mock objects.

Your code in its simplest form can be like this:

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"net/http"
  6. )
  8. type contact struct {
  9. 	username string
  10. 	number   int
  11. }
  13. type Client interface {
  14. 	Do(req *http.Request) (*http.Response, error)
  15. }
  17. func main() {
  18. 	getResponse(http.DefaultClient, contact{})
  19. }
  21. func getResponse(client Client, c contact) string {
  22.   url := fmt.Sprintf("https://mywebsite/%s", c.username)
  23.   req, _ := http.NewRequest(http.MethodGet, url, nil)
  24.   // error checking
  26.   resp, _ := http.DefaultClient.Do(req)
  27.   // error checking and response processing
  29.   return response
  30. }

And your test can be like this:

  1. package main
  3. import (
  4. 	"net/http"
  5. 	"testing"
  6. )
  8. type mockClient struct {
  9. }
  11. // Do function will cause mockClient to implement the Client interface
  12. func (tc mockClient) Do(req *http.Request) (*http.Response, error) {
  13. 	return &http.Response{}, nil
  14. }
  16. func TestGetResponse(t *testing.T) {
  17. 	client := new(mockClient)
  18. 	getResponse(client, contact{})
  19. }

But if you prefer to use httptest:

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"io"
  6. 	"net/http"
  7. 	"net/http/httptest"
  8. )
  10. type contact struct {
  11. 	username string
  12. 	number   int
  13. }
  15. func main() {
  16. 	fmt.Println(getResponse(contact{}))
  17. }
  19. func getResponse(c contact) string {
  20. 	// Make a test server
  21. 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  22. 		fmt.Fprintln(w, "your response")
  23. 	}))
  25. 	defer ts.Close()
  27. 	// You should still set your base url
  28. 	base_url := ts.URL
  30. 	url := fmt.Sprintf("%s/%s", base_url, c.username)
  31. 	req, _ := http.NewRequest(http.MethodGet, url, nil)
  33. 	// Use ts.Client() instead of http.DefaultClient in your tests.
  34. 	resp, _ := ts.Client().Do(req)
  36. 	// Processing the response
  37. 	response, _ := io.ReadAll(resp.Body)
  38. 	resp.Body.Close()
  40. 	return string(response)
  41. }

答案2

得分: 0

你可以使用https://pkg.go.dev/net/http/httptest#example-Server作为一个很好的例子，通过对你的代码进行一些小的重构来满足你的使用情况。

你只需要将getResponse()更改为getResponse(url string)，以便能够提供服务器模拟的URL。

英文:

https://pkg.go.dev/net/http/httptest#example-Server is a good example for your use case with a small refactoring of your code.

You just have to change the getResponse() by getResponse(url string) to be able to give the server mock url.

huangapple
  • 本文由 发表于 2023年1月4日 18:19:15
  • 转载请务必保留本文链接：https://go.coder-hub.com/75003986.html
  • go
  • http
  • mocking
  • testing
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