#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1e5+5;
ll n, T, bit[maxn], a[maxn];

void add (int x, ll v){
    while(x<=n){
        bit[x] += v;
        x += (x&(-x));
    } 
}

ll query(int x) {
    ll ans =0;
    while (x>0){
        ans += bit[x];
        x-=(x&(-x));
    }
    return ans;
}

int main (){
    ios::sync_with_stdio(false);
  //  freopen("in.txt","r",stdin);
    int T;
    cin >> T; 
    while (T--){
        memset(bit,0,sizeof(bit));
        cin >> n;
        for (int i=1; i<=n; i++)
            cin >> a[i];
        sort(a+1,a+n+1);
        for (int i=1; i<=n; i++)
            add(i,a[i]);
        ll ans = 0;
        for (int i=2; i<=n; i++){
            ans += (i-1)*a[i]-query(i-1);
        }
        cout << ans << endl;
    }
    return 0;
}