在Golang中模拟函数，而无需使用函数类型或将模拟函数作为参数传递

I want to test LoadPage and GetData function. While testing LoadPage, I want to mock GetData function, how to do that? Don't want to use something like this type PageGetter func(url string) string and pass mock func as parameter

package main

import (
    "net/http"
    "os"
    "fmt"
    "io/ioutil"
)

func GetData(url string) (*http.Response,error){
    return http.Get(url)
}

func LoadPage(url string) {

    resp,err := GetData(url)
    if err != nil {
        os.Exit(0)
    }
    data,err :=ioutil.ReadAll(resp.Body)
    fmt.Println(string(data))
}

func main()  {
    var url string
    fmt.Scanf("%s", &url)
    LoadPage(url)
}