#include <bits/stdc++.h>
using namespace std;
int arr[100007];
int main() {
  int n;
  cin >> n;
  int k = 0;
  while (k < n) {
    int t;
    cin >> t;
    for (int i = 0; i < t; i++) {
      cin >> arr[i];
    }
    sort(arr, arr + t);
    if (t % 2) cout << arr[t / 2] << " ";
    for (int i = t / 2 - 1; i >= 0; i--) {
      cout << arr[t - i - 1] << " " << arr[i];
      if (i != 0) cout << " ";
    }
    cout << endl;
    k++;
  }
  return 0;
}
