#include <bits/stdc++.h>
using namespace std;
int main() {
  long long t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    long long a[n];
    for (long long i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    int i = 0, j = n - 1, k = n - 1;
    long long arr[n];
    while (k >= 0) {
      arr[k] = a[j];
      --k;
      if (k < 0) break;
      arr[k] = a[i];
      --k;
      ++i, --j;
    }
    for (long long i = 0; i < n; i++) cout << arr[i] << " ";
    cout << "\n";
  }
}
