#include <bits/stdc++.h>
using namespace std;
int t, n, x;
int main() {
  scanf("%d", &t);
  while (t--) {
    scanf("%d", &n);
    vector<int> a, res;
    a.clear(), res.clear();
    for (int i = int(0); i <= int(n) - 1; i++) {
      scanf("%d", &x);
      a.push_back(x);
    }
    sort(a.begin(), a.end());
    int i = 0, j = n - 1;
    while (i < j) {
      res.push_back(a[j]);
      res.push_back(a[i]);
      i++, j--;
    }
    if (int(res.size()) != n) res.push_back(a[i]);
    for (int i = int(n) - 1; i >= int(0); i--) {
      cout << res[i] << " ";
    }
    cout << "\n";
  }
  return 0;
}
