#include <bits/stdc++.h>
using namespace std;
long long a[100099], ans[100099];
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long tt;
  cin >> tt;
  while (tt--) {
    long long n;
    cin >> n;
    for (long long i = 0; i < n; i++) {
      cin >> a[i];
    }
    sort(a + 0, a + n);
    long long l = 0, r = n - 1;
    for (long long i = n - 1; i >= 0; i--) {
      if (i % 2) {
        ans[i] = a[l];
        l++;
      } else {
        ans[i] = a[r];
        r--;
      }
    }
    for (long long i = 0; i < n; i++) cout << ans[i] << " ";
    cout << "\n";
  }
}
