Go 使用 httptest 对 http 请求进行单元测试重试

NewUnstartedServer就是这么简单:

func NewUnstartedServer(handler http.Handler) *Server {
    return &Server{
        Listener: newLocalListener(),
        Config:   &http.Server{Handler: handler},
    }
}

如果您自己 Select 一个端口有效，您可以这样做:

func MyNewUnstartedServer(port int, handler http.Handler) *httptest.Server {
    addr := fmt.Sprintf("127.0.0.1:%d", port)
    l, err := net.Listen("tcp", addr)
    if err != nil {
        addr = fmt.Sprintf("[::1]::%d", port)
        if l, err = net.Listen("tcp6", addr); err != nil {
            panic(fmt.Sprintf("httptest: failed to listen on a port: %v", err))
        }
    }
    return &httptest.Server{
        Listener: l,
        Config:   &http.Server{Handler: handler},
    }
}

创建监听程序的代码从httptest.newLocalListener修改.

另一种 Select 是实现http.RoundTripper接口，并使用此往返程序创建http.Client.下面是一个抄袭自net/http/client_test.go的例子:

type recordingTransport struct {
    req *Request
}

func (t *recordingTransport) RoundTrip(req *Request) (resp *Response, err error) {
    t.req = req
    return nil, errors.New("dummy impl")
}

func TestGetRequestFormat(t *testing.T) {
    setParallel(t)
    defer afterTest(t)
    tr := &recordingTransport{}
    client := &Client{Transport: tr}
    url := "http://dummy.faketld/"
    client.Get(url) // Note: doesn't hit network
    if tr.req.Method != "GET" {
        t.Errorf("expected method %q; got %q", "GET", tr.req.Method)
    }
    if tr.req.URL.String() != url {
        t.Errorf("expected URL %q; got %q", url, tr.req.URL.String())
    }
    if tr.req.Header == nil {
        t.Errorf("expected non-nil request Header")
    }
}