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