#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    int n, c, b;
    cin >> n;
    int a[n];
    for (long long int i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    c = n / 2;
    b = n / 2 - 1;
    if (n % 2) {
      cout << a[n / 2] << " ";
      c++;
    }
    while (n / 2) {
      cout << a[c] << " " << a[b] << " ";
      c++;
      b--;
      n -= 2;
    }
    cout << "\n";
  }
}
