# include <bits/stdc++.h>
using namespace std;
namespace Base{
    # define mr make_pair
    typedef long long ll;
    typedef double db;
    const int inf = 0x3f3f3f3f, INF = 0x7fffffff;
    const ll  infll = 0x3f3f3f3f3f3f3f3fll, INFll = 0x7fffffffffffffffll;
    template<typename T> void read(T &x){
        x = 0; int fh = 1; double num = 1.0; char ch = getchar();
        while (!isdigit(ch)){ if (ch == '-') fh = -1; ch = getchar(); }
        while (isdigit(ch)){ x = x * 10 + ch - '0'; ch = getchar(); }
        if (ch == '.'){
            ch = getchar();
            while (isdigit(ch)){num /= 10; x = x + num * (ch - '0'); ch = getchar();}
        }
        x = x * fh;
    }
    template<typename T> void chmax(T &x, T y){x = x < y ? y : x;}
    template<typename T> void chmin(T &x, T y){x = x > y ? y : x;}
}
using namespace Base;

const int N = 100010;
int n, a[N], T;
ll sum[N], ans;
int main(){
    read(T);
    while (T--){
        ans = 0;
        read(n);
        for (int i = 1; i <= n; i++) read(a[i]);
        sort(a + 1, a + n + 1);
        sum[n + 1] = 0;
        for (int i = n; i >= 1; i--) sum[i] = sum[i + 1] + a[i];
        for (int i = 1; i <= n; i++)
            ans = ans + sum[i + 1] - 1ll * a[i] * (n - i);
        cout << ans << endl;
    }
    return 0;
}