#include <bits/stdc++.h>
using namespace std;
const int maxn=1e5+5;
typedef long long ll;
ll dis[maxn];
ll sum[maxn];
int n, m, k, l, s, t, r, p;
int main() {
   
    int T;
    cin >> T;
    while (T--) {
       scanf("%d",&n);
       for(int i=1;i<=n;i++)
           scanf("%lld",&dis[i]);
            sort(dis+1,dis+1+n);
            for(int i=1;i<=n;i++)
            sum[i]=0;
    for(int i=1;i<=n;i++)
        sum[i]+=sum[i-1]+dis[i];
        ll ans=0;
        for(int i=1;i<=n;i++){
        
            ans+=sum[n]-(long long)(n-i+1)*dis[i]-sum[i-1];
//            cerr<<sum[n]-(long long)(n-i+1)*dis[i]-sum[i-1]<<endl; 
        }
        cout<<ans<<endl;
        
        
    }
   
    

    return 0;
}