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