#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<int> a(n), ans(n);
  int pos = 0;
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a.begin(), a.end());
  int l = 0, r = n - 1;
  while (l < r) {
    ans[pos++] = a[l];
    ans[pos++] = a[r];
    ++l, --r;
  }
  if (l == r) {
    ans[pos] = a[l];
  }
  reverse(ans.begin(), ans.end());
  for (int i = 0; i < (int)ans.size(); ++i) cout << ans[i] << " ";
  cout << "\n";
  ;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
}
