#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n, greater<int>());
    int ans[n], cnt = n - 1;
    for (int i = 0; 2 * i < n; i++) {
      ans[cnt] = a[i];
      cnt -= 2;
    }
    cnt = n - 2;
    for (int i = n - 1; 2 * i >= n; i--) {
      ans[cnt] = a[i];
      cnt -= 2;
    }
    for (int i = 0; i < n; i++) cout << ans[i] << " ";
    cout << "\n";
  }
  return 0;
}
