#include<iostream>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<cstring>
#include<string>
#include<cmath>
#include<ctime>
#include<algorithm>
#define LL long long
#define PII pair<int,int>
#define pi acos(-1.0)
#define lowbit(x) x&(-x)
using namespace std;

const int maxn=100010;
int T,n;
LL a[maxn];

int main(void){
    scanf("%d",&T);
    while(T--){
        scanf("%d",&n);
        for(int i=0;i<n;i++) scanf("%d",&a[i]);
        sort(a,a+n);
        LL ans=0;
        for(int i=0;i<n;i++){
            ans+=a[i]*(2*i+1-n);
        }
        printf("%lld\n",ans);
    }
    return 0;
}