#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<set>
#include<map>
using namespace std;
typedef long long ll;
const int maxn = 2000 + 100;
const int mod = 1e9 + 7;
#define f(x) (x+x)
typedef long long ll;
long long sum[100010];
int a[100010];
int main(){
    int t;
    scanf("%d", &t);
    while(t--){
        int n;
        scanf("%d", &n);
        for(int i = 0; i < n; ++i){
            
            scanf("%d", &a[i]);
           // sum[i+1] = sum[i] + a[i];
        }
        sort(a, a + n);
        long long ans = 0;
        sum[0] = 0;
        for(int i = 0; i < n; ++i) sum[i+1] = sum[i] + a[i];
        for(int i = 0; i < n; ++i){
            ans += sum[n] - sum[i] - (long long)(n-i)*a[i];
        }
        printf("%lld\n", ans);
    }
    return 0;
}