Mocking function in Golang

I want to test LoadPage and GetData function. While testing LoadPage, I want to mock GetData function, how to do that?

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)
}