#include <bits/stdc++.h>
using namespace std;
int i = 0, j = 0, k;
int main() {
  int t, n;
  cin >> t;
  while (t--) {
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; ++i) cin >> arr[i];
    sort(arr, arr + n);
    if (n & 1) {
      int q = n / 2;
      cout << arr[q] << " ";
      i = q + 1;
      --q;
      bool l = true, r = false;
      while (q >= 0 || i < n) {
        if (l && q > -1) {
          cout << arr[q] << " ";
          l = false;
          r = true;
          --q;
          continue;
        }
        if (r && i < n) {
          cout << arr[i] << " ";
          r = false, l = true;
          ++i;
        }
      }
      cout << endl;
    } else {
      i = (n - 1) / 2;
      j = i + 1;
      bool l = true, r = false;
      while (i > -1 || j < n) {
        if (l && i > -1) {
          cout << arr[i] << " ";
          l = false;
          r = true;
          --i;
          continue;
        }
        if (r && j < n) {
          cout << arr[j] << " ";
          r = false;
          l = true;
          ++j;
        }
      }
      cout << endl;
    }
  }
}
