#include <bits/stdc++.h>
using namespace std;
int main() {
  int k;
  cin >> k;
  for (int c = 0; c < k; ++c) {
    int n;
    cin >> n;
    vector<int> v(n);
    for (int i = 0; i < n; ++i) cin >> v[i];
    sort(v.rbegin(), v.rend());
    int w[n];
    for (int i = 0; i < (n + 1) / 2; ++i) {
      int j = i * 2;
      w[j] = v[i];
      if (n % 2 == 0 || i != (n + 1) / 2 - 1) w[j + 1] = v[n - i - 1];
    }
    for (int i = n - 1; i >= 0; --i) cout << w[i] << " ";
    cout << endl;
  }
  return 0;
}
