#include <bits/stdc++.h>
using namespace std;
int main() {
  long long t, n, i, mid, ct, flag, val;
  cin >> t;
  while (t--) {
    ct = 0;
    flag = 1;
    cin >> n;
    long long a[n];
    for (i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    if (n % 2)
      mid = n / 2;
    else
      mid = (n / 2) - 1;
    while (ct != n) {
      cout << a[mid] << " ";
      ct++;
      if (flag) {
        mid = mid + ct;
        flag = 0;
      } else {
        mid = mid - ct;
        flag = 1;
      }
    }
    cout << endl;
  }
}
