#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

#define int long long

void solve() {
    int n;
    vector<long long> vect;
    cin >> n;
    for (int i = 0; i < n; i++) {
        long long x;
        cin >> x;
        vect.push_back(x);
    }
    sort(vect.begin(), vect.end());
    long long res = 0;
    long long now = 0;
    for (int i = n - 2; i >= 0; i--) {
        res -= now - (n - i - 2) * vect[i];
        now += vect[i + 1];
    }
    cout << res << "\n";
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    for (int i = 0; i < t; i++)
        solve();
    return 0;
}
