#include<iostream>
#include<stdio.h>
#include <algorithm>
using namespace std;
bool cmp1(int a,int b)//int为数组数据类型
{
return a>b;//降序排列
//return a<b;//默认的升序排列
}
 int a[100010];
int main(){
    int test;
    scanf("%d", &test);
    for(;test > 0; test--){
        int sum = 0;
        int i, n;
        scanf("%d", &n);
        for(i = 0; i < n; i++){
            scanf("%d", &a[i]);
        }
        sort(a,a+n, cmp1);
        long long val = 0, tmp = 0;
        for(i = 1; i < n; i++){
            tmp += a[0]-a[i];
        }
        val += tmp;
       // printf("i=%d tmp=%lld   val=%lld\n", 0, tmp, val);
        for(i = 1; i < n; i++){
            long long d = a[i-1] - a[i];
            tmp -= (n-i)*d;
            val += tmp;
           // printf("i=%d tmp=%lld   val=%lld\n", i, tmp, val);
        }
        printf("%lld\n", val);
    }
}