#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long* arr = new long long[n];
    for (long long i = 0; i < n; i++) {
      cin >> arr[i];
    }
    sort(arr, arr + n);
    long long i, j;
    if (n % 2 == 0) {
      j = n / 2;
      i = j - 1;
    } else {
      i = n / 2;
      cout << arr[i] << " ";
      j = i + 1;
      i--;
    }
    while (i >= 0 && j < n) {
      cout << arr[j] << " " << arr[i] << " ";
      i--;
      j++;
    }
    cout << endl;
  }
}
