#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    int arr1[n + 1], arr2[n + 1];
    for (int i = 0; i < n; i++) {
      cin >> arr1[i];
    }
    sort(arr1, arr1 + n);
    long long int count = n - 1;
    for (int i = 0; i < n / 2; i++) {
      arr2[count] = arr1[n - i - 1];
      count--;
      arr2[count] = arr1[i];
      count--;
    }
    if (n % 2 != 0) {
      arr2[count] = arr1[n / 2];
    }
    for (int i = 0; i < n; i++) {
      cout << arr2[i] << " ";
    }
    cout << "\n";
  }
}
