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