#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int a[n];
    for (int &i : a) {
      cin >> i;
    }
    sort(a, a + n);
    int l = n / 2 - 1, r = n / 2;
    if (n % 2) {
      cout << a[r++] << " ";
    }
    while (l != -1) {
      cout << a[l--] << " " << a[r++] << " ";
    }
    cout << "\n";
  }
  return 0;
}
