#include <bits/stdc++.h>
using namespace std;
long long f[100010];
long long T, n;
int main() {
  cin >> T;
  while (T--) {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> f[i];
    sort(f + 1, f + 1 + n);
    if (n % 2) {
      cout << f[n / 2 + 1] << " ";
      for (int i = n / 2; i >= 1; i--)
        cout << f[i] << " " << f[n + 1 - i] << " ";
    } else
      for (int i = 0; i < n / 2; i++)
        cout << f[n / 2 - i] << " " << f[n / 2 + 1 + i] << " ";
    cout << endl;
  }
  return 0;
}
