Golang中HTTP服务器的测试指南

以下是针对您测试HTTP服务器实现中遇到问题的专业解答。

关于空请求体的处理

在Go中，使用http.NewRequest创建请求时，即使传入nil作为body，r.Body也不会是nil，而是一个空的io.ReadCloser。这就是为什么您的空指针检查失败的原因。

正确的空请求体测试方法：

t.Run("Send POST without body, expect 422", func(t *testing.T) {
    request, _ := http.NewRequest(http.MethodPost, "/myPath", bytes.NewReader(nil))
    request.Header.Set("Content-Type", "application/json")
    response := httptest.NewRecorder()

    server.ServeHTTP(response, request)
    
    assertResponseStatus(t, response.Code, http.StatusUnprocessableEntity)
})

改进的请求处理器实现

func myPathHandler(w http.ResponseWriter, r *http.Request) {
    // 检查请求体是否为空
    if r.Body == nil {
        http.Error(w, "Request body is required", http.StatusUnprocessableEntity)
        return
    }
    
    // 读取请求体内容
    bodyBytes, err := ioutil.ReadAll(r.Body)
    if err != nil {
        http.Error(w, "Failed to read request body", http.StatusInternalServerError)
        return
    }
    
    // 检查请求体是否为空
    if len(bodyBytes) == 0 {
        http.Error(w, "Request body cannot be empty", http.StatusUnprocessableEntity)
        return
    }
    
    // 解析JSON
    var requestBody myPathRequestBody
    if err := json.Unmarshal(bodyBytes, &requestBody); err != nil {
        http.Error(w, "Invalid JSON format", http.StatusUnprocessableEntity)
        return
    }
    
    // 继续处理有效请求...
}

完整的测试套件示例

func TestServer(t *testing.T) {
    server := NewServer()
    
    // 测试不支持的方法
    t.Run("Send GET, expect 405", func(t *testing.T) {
        request, _ := http.NewRequest(http.MethodGet, "/myPath", nil)
        response := httptest.NewRecorder()
        
        server.ServeHTTP(response, request)
        assertResponseStatus(t, response.Code, http.StatusMethodNotAllowed)
    })
    
    t.Run("Send PUT, expect 405", func(t *testing.T) {
        request, _ := http.NewRequest(http.MethodPut, "/myPath", nil)
        response := httptest.NewRecorder()
        
        server.ServeHTTP(response, request)
        assertResponseStatus(t, response.Code, http.StatusMethodNotAllowed)
    })
    
    // 测试空请求体
    t.Run("Send POST without body, expect 422", func(t *testing.T) {
        request, _ := http.NewRequest(http.MethodPost, "/myPath", bytes.NewReader(nil))
        request.Header.Set("Content-Type", "application/json")
        response := httptest.NewRecorder()
        
        server.ServeHTTP(response, request)
        assertResponseStatus(t, response.Code, http.StatusUnprocessableEntity)
    })
    
    // 测试无效JSON
    t.Run("Send POST with invalid JSON, expect 422", func(t *testing.T) {
        invalidJSON := []byte(`{"invalid": json}`)
        request, _ := http.NewRequest(http.MethodPost, "/myPath", bytes.NewReader(invalidJSON))
        request.Header.Set("Content-Type", "application/json")
        response := httptest.NewRecorder()
        
        server.ServeHTTP(response, request)
        assertResponseStatus(t, response.Code, http.StatusUnprocessableEntity)
    })
    
    // 测试缺少必需字段
    t.Run("Send POST with missing required field, expect 422", func(t *testing.T) {
        incompleteJSON := []byte(`{"optionalField": "value"}`)
        request, _ := http.NewRequest(http.MethodPost, "/myPath", bytes.NewReader(incompleteJSON))
        request.Header.Set("Content-Type", "application/json")
        response := httptest.NewRecorder()
        
        server.ServeHTTP(response, request)
        assertResponseStatus(t, response.Code, http.StatusUnprocessableEntity)
    })
}

func assertResponseStatus(t *testing.T, got, want int) {
    t.Helper()
    if got != want {
        t.Errorf("got status %d, want %d", got, want)
    }
}

使用gorilla/mux的路由配置

func NewServer() *mux.Router {
    router := mux.NewRouter()
    router.Handle("/mypath", http.HandlerFunc(myPathHandler)).Methods("POST")
    return router
}

请求体结构定义

type myPathRequestBody struct {
    RequiredField string `json:"requiredField"`
    OptionalField string `json:"optionalField,omitempty"`
}

您对状态码的选择是正确的。422 Unprocessable Entity适用于语义错误（如缺少必需字段），而400 Bad Request适用于语法错误。这种区分确实有助于API客户端更好地理解问题所在。