#include <bits/stdc++.h>
using namespace std;
void pr(long long x, bool fl = false) {
  cout << x << endl;
  if (fl) exit(0);
}
void pr(long long x[], long long n, bool fl = false) {
  for (long long i = 1; i <= n; i++) cout << x[i] << (i == n ? '\n' : ' ');
  if (fl) exit(0);
}
long long a[100008];
signed main() {
  ios::sync_with_stdio(false);
  long long test_case;
  cin >> test_case;
  while (test_case--) {
    long long n;
    cin >> n;
    for (long long i = 1; i <= n; i++) {
      cin >> a[i];
    }
    sort(a + 1, a + n + 1);
    long long l = n / 2, r = n / 2 + 1;
    if (n % 2 == 1) l++, r++;
    while (l >= 1 and r <= n) {
      cout << a[l] << " " << a[r] << " ";
      l--, r++;
    }
    if (l >= 1)
      cout << a[l] << endl;
    else if (r <= n)
      cout << a[r] << endl;
    else
      cout << endl;
  }
  return 0;
}
