#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fll;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int t;
  cin >> t;
  int n;
  for (int i = 0; i < t; i++) {
    cin >> n;
    vector<int> v(n);
    for (int j = 0; j < n; j++) {
      cin >> v[j];
    }
    sort(v.begin(), v.end());
    int center = n / 2;
    if (n % 2 == 1) {
      cout << v[center] << " ";
    }
    for (int k = center - 1; k >= 0; k--) {
      cout << v[k] << " " << v[n - k - 1];
      if (k != 0)
        cout << " ";
      else
        cout << '\n';
    }
  }
  return 0;
}
