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