#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

template<class Type>
inline void R(Type &x) {
    int c = getchar();
    bool neg = 0;
    for (; c < 48 || c > 57; c = getchar())if (c == '-')neg = true;
    for (x = 0; c > 47 && c < 58; x = (Type) 10 * x + c - 48, c = getchar());
    if (neg)x = -x;
}

long long ans, a[100010];
int n;

int main() {
    int T;
    R(T);
    while (T--) {
        ans = 0;
        R(n);
        for (int i = 1; i <= n; ++i)
            R(a[i]);
        sort(a + 1, a + 1 + n);
        int m = n - 1;
        for (int i = 1; i <= n; ++i) {
            ans -= m * a[i];
            m -= 2;
        }
        printf("%lld\n", ans);
    }
    return 0;
}