#include <bits/stdc++.h>
using namespace std;
int main() {
  int t, n, l, r, i;
  long int a[100000], b[100000];
  cin >> t;
  while (t--) {
    cin >> n;
    for (i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    l = 0;
    r = n - 1;
    i = 0;
    while (i < n) {
      if (i % 2 == 0) {
        b[i] = a[r];
        r--;
      } else {
        b[i] = a[l];
        l++;
      }
      i++;
    }
    reverse(b, b + n);
    for (i = 0; i < n; i++) cout << b[i] << " ";
    cout << endl;
  }
}
