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