#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long arr[n];
    for (long long i = 0; i < n; i++) cin >> arr[i];
    sort(arr, arr + n);
    vector<long long> ans;
    for (long long i = 0; i < (n / 2); i++) {
      ans.push_back(arr[n - 1 - i]);
      ans.push_back(arr[i]);
    }
    if (n % 2) ans.push_back(arr[n / 2]);
    for (long long i = n - 1; i >= 0; i--) cout << ans[i] << " ";
    cout << endl;
  }
}
