#include <cstdio>
#include <algorithm>
using namespace std;

#define LL long long
const int MX = 1e5 + 233;
LL A[MX] ,S[2][MX];
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)
            S[0][i] = S[0][i - 1] + A[i];
        for(int i = n ; i ; --i)
            S[1][i] = S[1][i + 1] + A[i];
        LL Ans = 0;
        for(int i = 1 ; i <= n ; ++i){
            Ans += i * A[i] - S[0][i];
            Ans += -(n - i + 1) * A[i] + S[1][i];
        }
        printf("%lld\n" ,Ans / 2);
    }return 0;
}