#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int tt = 1;
  cin >> tt;
  while (tt--) {
    int n;
    cin >> n;
    int A[n];
    for (int i = 0; i < n; i++) {
      cin >> A[i];
    }
    int cnt = 0;
    sort(A, A + n);
    int left, right;
    if (n % 2 == 0) {
      left = n / 2 - 1;
      right = n / 2;
    } else {
      left = n / 2;
      right = n / 2 + 1;
    }
    while (cnt < n) {
      cout << A[left] << " ";
      left--;
      cnt++;
      if (cnt == n) {
        break;
      }
      cout << A[right] << " ";
      right++;
      cnt++;
    }
    cout << '\n';
  }
  return 0;
}
