如何在 go 中使用 martini 测试反向代理

Question

我正在为在 go 中作为反向代理工作的 martini 应用程序编写测试代码，并想使用 httptest.ResponseRecorder 对其进行测试，但出现以下错误。

[martini] PANIC: interface conversion: *httptest.ResponseRecorder is not http.CloseNotifier: missing method CloseNotify

httptest.ResponseRecorder 没有方法CloseNotify()

我应该如何测试它？

package main

import (
        "github.com/go-martini/martini"
        "github.com/stretchr/testify/assert"
        "net/http"
        "net/http/httptest"
        "net/http/httputil"
        "net/url"
        "testing"
)

func TestReverseProxy(t *testing.T) {
        // Mock backend
        backendResponse := "I am the backend"
        backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
                w.Write([]byte(backendResponse))
        }))
        defer backend.Close()
        backendURL, _ := url.Parse(backend.URL)

        // Frontend
        m := martini.Classic()
        m.Get("/", func(w http.ResponseWriter, r *http.Request) {
                proxy := httputil.NewSingleHostReverseProxy(backendURL)
                proxy.ServeHTTP(w, r)
        })

        // Testing
        req, _ := http.NewRequest("GET", "/", nil)
        res := httptest.NewRecorder()
        m.ServeHTTP(res, req)

        assert.Equal(t, 200, res.Code, "should be equal")
}

Answer 1

首先，请注意，martini 框架不再像他们的README 中所说的那样维护。

然后，关于您的问题，这是因为 Martini 做了一些对我来说看起来很糟糕的事情：它需要一个 http.ResponseWriter 并假设它也是一个 http.CloseNotifier，但绝对不能保证这一点。他们应该采用一个自定义界面来包装它们，就像这样：

type ResponseWriterCloseNotifier interface {
    http.ResponseWriter
    http.CloseNotifier
}

您可以在他们的源代码中看到他们在自己的测试中遇到了同样的问题，并使用了一些解决方法：https://github.com/go-martini/martini/commit/063dfcd8b0f64f4e2c97f0bc27fa422969baa23b#L13

这是一些用它制作的工作代码：

package main

import (
    "net/http"
    "net/http/httptest"
    "net/http/httputil"
    "net/url"
    "testing"

    "github.com/go-martini/martini"
    "github.com/stretchr/testify/assert"
)

type closeNotifyingRecorder struct {
    *httptest.ResponseRecorder
    closed chan bool
}

func newCloseNotifyingRecorder() *closeNotifyingRecorder {
    return &closeNotifyingRecorder{
        httptest.NewRecorder(),
        make(chan bool, 1),
    }
}

func (c *closeNotifyingRecorder) close() {
    c.closed <- true
}

func (c *closeNotifyingRecorder) CloseNotify() <-chan bool {
    return c.closed
}

func TestReverseProxy(t *testing.T) {
    // Mock backend
    backendResponse := "I am the backend"
    backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte(backendResponse))
    }))
    defer backend.Close()
    backendURL, _ := url.Parse(backend.URL)

    // Frontend
    m := martini.Classic()
    m.Get("/", func(w http.ResponseWriter, r *http.Request) {
        proxy := httputil.NewSingleHostReverseProxy(backendURL)
        proxy.ServeHTTP(w, r)
    })

    // Testing
    req, _ := http.NewRequest("GET", "/", nil)
    res := newCloseNotifyingRecorder()
    m.ServeHTTP(res, req)

    assert.Equal(t, 200, res.Code, "should be equal")
}