#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define fir first
#define sec second
#define rep(i,a,b) for (int i = (a); i <= (b); ++ i)
#define rrp(i,a,b) for (int i = (a); i >= (b); -- i)
#define gc() getchar()
template <typename tp>
inline void read(tp& x) {
  x = 0; char tmp; bool key = 0;
  for (tmp = gc(); !isdigit(tmp); tmp = gc())
    key = (tmp == '-');
  for (; isdigit(tmp); tmp = gc())
    x = (x << 3) + (x << 1) + (tmp ^ '0');
  if (key) x = -x;
}
template <typename tp>
inline void ckmn(tp& x,tp y) {
  x = x < y ? x : y;
}
template <typename tp>
inline void ckmx(tp& x,tp y) {
  x = x < y ? y : x;
}


const int N = 100010;
int n, val[N];
ll sum[N], ans;
void solve() {
  read(n);
  rep (i, 1, n) read(val[i]);
  sort(val + 1, val + n + 1);
  rep (i, 1, n) sum[i] = val[i] + sum[i-1];
  ans = 0;
  rep (i, 1, n) {
    ans += (sum[n] - sum[i]) - (ll)(n - i) * val[i];
  }
  printf("%lld\n", ans);
}
int main() {
  int T;
  read(T);
  while (T --)
    solve();
  return 0;
}