#include <bits/stdc++.h>
using namespace std;
int main() {
  int q;
  cin >> q;
  while (q--) {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    }
    sort(a, a + n);
    int hz[n];
    int cnt = 0;
    int l = (n + 1) / 2 - 1;
    int r = l + 1;
    while (l != -1 && r != n + 1) {
      hz[cnt] = a[l];
      hz[cnt + 1] = a[r];
      l--;
      r++;
      cnt += 2;
    }
    for (int i = 0; i < n; i++) cout << hz[i] << ' ';
    cout << endl;
  }
  return 0;
}
