#include <bits/stdc++.h>

using namespace std;
#define sz(a) (int)(a).size()
#define rep(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define debug(a) cerr << #a << ": " << (a) << '\n';
#define debug_arr(a, n) { cerr << #a << " "; rep(i, 0, n) cerr << a[i] << " \n"[(i + 1) == n]; }
#define debug_two(a, b) cerr << #a << ": " << (a) << ", " << #b << ": " << (b) << '\n';

template <typename num_t>
inline void add_mod(num_t& a, const long long& b, const int& m) { a = (a + b) % m; if (a < 0) a += m; }
template <typename num_t>
inline bool update_max(num_t& a, const num_t& b) { return a < b ? a = b, true : false; }
template <typename num_t>
inline bool update_min(num_t& a, const num_t& b) { return a > b ? a = b, true : false; }
template <typename num_t>
num_t gcd(num_t lhs, num_t rhs) { return !lhs ? rhs : gcd(rhs % lhs, lhs); }
template <typename num_t>
num_t pw(num_t n, num_t k, num_t mod) {
  num_t res = 1; for (; k > 0; k >>= 1) { if (k & 1) res = 1ll * res * n % mod; n = 1ll * n * n % mod; } return res;
}

typedef long long int64;
const int inf = 1e9 + 7;

void solve() {
  int test;
  cin >> test;
  while (test-- > 0) {
    int n;
    cin >> n;
    vector<int> arr(n);
    rep(i, 0, n) cin >> arr[i];

    sort(arr.begin(), arr.end());
    int64 total = arr[n - 1];

    int64 pre_sum = 0;
    rep(i, 1, n) {
      pre_sum += 1ll * (arr[i] - arr[i - 1]) * i;
      total -= pre_sum;
    }

    cout << total << '\n';
  }
}

int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef _LOCAL_
  freopen("in.txt", "r", stdin);
#endif
  const bool multiple_test = false;
  int test = 1;
  if (multiple_test)
    cin >> test;

  for(int i = 0; i < test; ++i) {
    //printf("Case #%d: ", i + 1);
    solve();
  }
#ifdef _LOCAL_
  cerr << "\n" << 1.0 * clock() / CLOCKS_PER_SEC << "\n";
#endif
}
