#include <bits/stdc++.h>
#define ls rt<<1
#define rs rt<<1|1
using namespace std;

typedef  long long ll;
const int inf = 0x3f3f3f3f;
const int maxn = 1000001;

ll a[101000];
ll sum[101000];
int main() {
    int t;
    scanf("%d", &t);
    while(t--) {
        int n;
        scanf("%d", &n);
        for(int i = 1; i <= n; i++){
            scanf("%lld", &a[i]);
        }
        sort(a+1,a+1+n);
        for(int i=1;i<=n;i++)  sum[i] = sum[i - 1] + a[i];
        ll ans = 0;
        for(int i = 1; i <= n; i++) {
            ans += (sum[n] - sum[i] - (n - i) * a[i]);
        }
        printf("%lld\n", ans);
    }
}