#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long a, i;
    vector<int> v;
    for (long long i = 0; i <= n - 1; i++) {
      cin >> a;
      v.push_back(a);
    }
    sort(v.begin(), v.end());
    int q = n % 2 == 0 ? n / 2 - 1 : n / 2;
    if (q == n / 2 - 1)
      for (long long i = q; i >= 0; i--) {
        cout << v[i] << " " << v[n - i - 1] << " ";
      }
    else {
      cout << v[q] << " ";
      for (long long i = q - 1; i >= 0; i--) {
        cout << v[i] << " " << v[n - i - 1] << " ";
      }
    }
    cout << endl;
  }
  return 0;
}
