#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k, i, j, mid, f;
  int t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long a[n + 5];
    for (i = 0; i < n; i++) {
      cin >> a[i];
    }
    sort(a, a + n);
    mid = n / 2;
    i = mid;
    j = mid + 1;
    if (n % 2 == 0) {
      i--;
      j--;
    }
    f = 1;
    while (1) {
      if (j >= n && i < 0) break;
      if (f % 2) {
        cout << a[i] << " ";
        i--;
        f++;
      } else {
        cout << a[j] << " ";
        j++;
        f++;
      }
    }
    cout << endl;
  }
  return 0;
}
