#include <bits/stdc++.h>
using namespace std;
long long re() {
  long long x;
  scanf("%lld", &x);
  return x;
}
long long a[100533], b[100533];
void solve() {
  long long n = re();
  long long h = 1, t = n;
  for (long long i = 1; i <= n; ++i) a[i] = re();
  sort(a + 1, a + n + 1);
  for (long long i = n; i >= 1; --i) {
    if (i & 1)
      b[i] = a[h++];
    else
      b[i] = a[t--];
  }
  for (long long i = 1; i <= n; ++i) printf("%lld ", b[i]);
  puts("");
}
signed main() {
  long long T;
  cin >> T;
  while (T--) solve();
}
