#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  int arr[n];
  for (int i = 0; i < n; i++) cin >> arr[i];
  int i = n / 2 - 1, j = n / 2;
  sort(arr, arr + n);
  int x = 0;
  int ans[n];
  if (n % 2) ans[0] = arr[n / 2], x++, j++;
  for (; i >= 0 && j < n; i--, j++) {
    ans[x++] = arr[i];
    ans[x++] = arr[j];
  }
  for (int i = 0; i < n; i++) cout << ans[i] << " ";
  cout << endl;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
