#include <bits/stdc++.h>
using namespace std;
mt19937 RNG(chrono::steady_clock::now().time_since_epoch().count());
void solve() {
  long long n;
  cin >> n;
  long long ret[n + 1], result[n + 1];
  for (long long i = 0; i < n; i++) {
    cin >> ret[i];
  }
  sort(ret, ret + n);
  long long pos = n - 1;
  for (long long i = 0; i < n / 2; i++) {
    result[pos] = ret[n - i - 1];
    pos--;
    result[pos] = ret[i];
    pos--;
  }
  if (n % 2 != 0) {
    result[pos] = ret[n / 2];
  }
  for (long long i = 0; i < n; i++) {
    cout << result[i] << " ";
  }
  cout << "\n";
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long t = 1;
  cin >> t;
  for (long long i = 1; i < t + 1; i++) {
    solve();
  }
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
