#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using lli = long long int;
using ld = long double;
using ull = unsigned long long;
const int N = 2e5 + 5, inf = 2e9;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int arr[n + 5];
    vector<ll> ans;
    for (int i = 0; i < n; i++) cin >> arr[i];
    sort(arr, arr + n);
    int l = 0, r = n - 1;
    while (l <= r) {
      if (l == r)
        ans.push_back(arr[l++]);
      else {
        ans.push_back(arr[r--]);
        ans.push_back(arr[l++]);
      }
    }
    reverse(ans.begin(), ans.end());
    for (auto i : ans) cout << i << " ";
    cout << "\n";
  }
  return 0;
}
