#include <bits/stdc++.h>
using namespace std;
long long int ESP = 1e18;
long long int INF = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long int t;
  cin >> t;
  for (long long int i = 0; i < t; i++) {
    long long int n;
    cin >> n;
    long long int a[n];
    for (long long int i = 0; i < n; i++) cin >> a[i];
    vector<long long int> ans;
    sort(a, a + n);
    long long int p = 0, q = n - 1;
    while (q >= p) {
      ans.push_back(a[q]);
      ans.push_back(a[p]);
      p++;
      q--;
    }
    for (long long int i = n - 1; i >= 0; i--) cout << ans[i] << " ";
    cout << "\n";
  }
  return 0;
}
