我试图使用谷歌测试来测试C代码，但我遇到了一些问题，写存根系统功能，如：fopen，fclose，fread，fwrite，memcpy，memset，stat，...我不知道如何正确地将它们存根以覆盖函数中需要测试的所有分支。
例如，我有一个函数，如何测试它的存根fopen，fclose，fwrite，fread？只有存根，而不是模拟。

#include <stdio.h>
#include <stdlib.h>

int main(){
    FILE *f;
    //initialize the arr1 with values
    int arr1[5]={1,2,3,4,5};
    int arr2[5];
    int i=0;

    //open the file for write operation
    if((f=fopen("includehelp.txt","w"))==NULL){
        //if the file does not exist print the string
        printf("Cannot open the file...");
        exit(1);
    }
    //write the values on the file
    if((fwrite(arr1,sizeof(int),5,f))!=5){
        printf("File write error....\n");
    }
    //close the file
    fclose(f);

    //open the file for read operation
    if((f=fopen("includehelp.txt","r"))==NULL){
        //if the file does not exist print the string
        printf("Cannot open the file...");
        exit(1);
    }
    //read the values from the file and store it into the array
    if((fread(arr2,sizeof(int),5,f))!=5){
        printf("File write error....\n");
    }
    fclose(f);

    printf("The array content is-\n");
    for(i=0;i<5;i++){
        printf("%d\n",arr2[i]);
    }

    return 0;
}