#include <bits/stdc++.h>
using namespace std;
int arr[1000000];
int main() {
  int t;
  cin >> t;
  for (int o = 0; o < t; o++) {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) cin >> arr[i];
    sort(arr, arr + n);
    if (n % 2 == 1) cout << arr[n / 2] << " ";
    for (int i = n / 2 + n % 2; i < n; i++) {
      cout << arr[n - i - 1] << " " << arr[i] << " ";
    }
    cout << '\n';
  }
  return 0;
}
