#include <bits/stdc++.h>
using ll = long long;
using namespace std;
int main(int argc, char const* argv[]) {
  ios_base::sync_with_stdio(false), cin.tie(nullptr);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> a(n);
    for (int& it : a) {
      cin >> it;
    }
    sort(begin(a), end(a));
    int left = n / 2 - 1, right = n / 2;
    for (int i = 0; i < n / 2; ++i) {
      cout << a[right] << ' ' << a[left] << ' ';
      --left, ++right;
    }
    if (n & 1) {
      cout << a[n - 1];
    }
    cout << '\n';
  }
  return 0;
}
