
#include<bits/stdc++.h>


using namespace std;

using ll   = long long;
using ii   = pair   < int , int >;
using i3   = pair   < int , ii  >;
using li   = pair   < ll  , int >;
using lii  = pair   < ll  , ii  >;
using pll  = pair   < ll  , ll  >;
using vi   = vector < int       >;
using vl   = vector < ll        >;
using vii  = vector < ii        >;
using vli  = vector < li        >;
using vpll = vector < pll       >;
using vi3  = vector < i3        >;
using vlii = vector < lii       >;


const int N = 2e5 + 5;
const ll INF = 1e17 + 7;
const double eps = 1e-9 , PI = acos(-1);



int n , m;
ll a[N];
ll sum[N];

void solve(int testCase){

    scanf("%d" , &n);

    for(int i = 1 ; i <= n ; i ++) {
            scanf("%lld" , &a[i]);
    }
    sort(a + 1 , a + 1 + n);

    ll ans = 0;
    for(int i = 1 ; i <= n ; i ++) {
            sum[i] = a[i] + sum[i-1];
            if(i > 2) {
                    ans += (i - 2) * a[i] - sum[i-2];
            }
    }

    printf("%lld\n" , -ans);

}

int main(){

    int t = 1;
    scanf("%d" , &t);

    for(int testCase = 1 ; testCase <= t ; testCase ++){
            solve(testCase);
    }

    return 0;
}
