#include <bits/stdc++.h>
using namespace std;
const int N = 100 * 1000 + 10;
int t, n, a[N];
int main() {
  ios::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  cin >> t;
  while (t--) {
    vector<int> res;
    cin >> n;
    for (int i = 0; i < n; i++) cin >> a[i];
    sort(a, a + n);
    for (int i = 0; i < n / 2; i++)
      res.push_back(a[n - 1 - i]), res.push_back(a[i]);
    reverse(res.begin(), res.end());
    if (n & 1) cout << a[n / 2] << ' ';
    for (int x : res) cout << x << ' ';
    cout << '\n';
  }
  return 0;
}
