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

long long sum[1000010];
long long a[1000010];

int main() {
    ios::sync_with_stdio(0);
    int T;  cin >> T;
    while (T--) {
        int n;  cin >> n;
        for (int i = 1; i <= n; i++) cin >> a[i];
        sort(a + 1, a + 1 + n);
        for (int i = 1; i <= n; i++)
            sum[i] = sum[i - 1] + a[i];
        long long ans = 0;
        for (long long i = 1, j = n - 1; i <= n; i++, j--) {
            ans -= a[i] * j;
            ans += sum[n] - sum[i];
        }
        cout << ans << endl;
    }
}