#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  int dasf = 134253;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    int arr[n + 1], brr[n + 1];
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
    }
    sort(arr, arr + n);
    int idx = n - 1;
    for (int i = 0; i < n / 2; i++) {
      brr[idx] = arr[n - i - 1];
      idx--;
      brr[idx] = arr[i];
      idx--;
    }
    if (n % 2 != 0) {
      brr[idx] = arr[n / 2];
    }
    for (int i = 0; i < n; i++) {
      cout << brr[i] << " ";
    }
    cout << "\n";
  }
}
