httptest パッケージを使用して Go で HTTP 呼び出しをテストする方法

<code class="go">func HTTPPost(message interface{}, url string) (*http.Response, error) {
    // ... implementation
}</code>

<code class="go">import (
    "fmt"
    "net/http"
    "net/http/httptest"
    "testing"
)

func TestHTTPPost(t *testing.T) {
    // Create a mock HTTP server
    ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintln(w, `response from the mock server goes here`)

        // Assert over the request made by HTTPPost
        if r.URL.String() != expectedRequestURL || r.Method != expectedRequestMethod {
            t.Errorf("Unexpected request: %v", r)
        }
    }))
    defer ts.Close()

    // Set the URL of the mock server as the target URL for HTTPPost
    mockServerURL := ts.URL

    // Define the message to send to the mock server
    message := "the message you want to test"

    resp, err := HTTPPost(message, mockServerURL)

    // Assert over the response and error returned by HTTPPost
    // ... your assertions
}</code>