#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n, i, l, r;
    cin >> n;
    long long a[n];
    for (i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    if (n % 2) {
      l = n / 2 - 1;
      r = n / 2 + 1;
      cout << a[n / 2] << ' ';
      while (l >= 0 && r < n) {
        cout << a[r] << ' ';
        cout << a[l] << ' ';
        r++;
        l--;
      }
      cout << endl;
    } else {
      l = n / 2 - 1;
      r = n / 2;
      while (l >= 0 && r < n) {
        cout << a[r] << ' ';
        cout << a[l] << ' ';
        r++;
        l--;
      }
      cout << endl;
    }
  }
  return 0;
}
