#include <bits/stdc++.h>
using namespace std;
void fast() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
void solve() {
  int n;
  cin >> n;
  vector<int> v(n, 0);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  sort(v.begin(), v.end());
  if (n % 2 == 0) {
    n = n / 2;
    for (int i = 0; i < n; i++) {
      cout << v[n - i - 1] << " " << v[n + i] << " ";
    }
    cout << "\n";
  } else {
    n = n / 2;
    cout << v[n] << " ";
    for (int i = 1; i <= n; i++) {
      cout << v[n - i] << " " << v[n + i] << " ";
    }
    cout << "\n";
  }
}
int main(void) {
  fast();
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
}
