#include <bits/stdc++.h>
using namespace std;
const int sz = 1e5 + 100;
const int INF = 1e9;
const double eps = 1e-7;
void solve() {
  int n;
  cin >> n;
  vector<long long> a(n + 1, 0);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  sort(a.begin(), a.begin() + n);
  for (int i = n - 1; i > -1; i--) {
    cout << a[i % 2 ? n - 1 - i / 2 : i / 2] << ' ';
  }
  cout << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}
