#include <bits/stdc++.h>
using namespace std;
map<long long int, long long int> m;
int main() {
  long long int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    long long int a[n];
    for (long long int i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    long long int x = 0, y = n - 1, iff = 1;
    vector<long long int> v;
    for (long long int i = 0; i < n; i++) {
      if (iff) {
        v.push_back(a[y]);
        y--;
        iff = 0;
      } else {
        v.push_back(a[x]);
        x++;
        iff = 1;
      }
    }
    for (long long int i = n - 1; i >= 0; i--) cout << v[i] << " ";
    cout << endl;
  }
}
