#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 10;
vector<int> a;
deque<int> ans;
void solve() {
  a.clear();
  ans.clear();
  int n, tmp;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &tmp);
    a.push_back(tmp);
  }
  sort(a.begin(), a.end());
  for (int i = 0; i < n / 2; i++) {
    ans.push_back(a[n - i - 1]);
    ans.push_back(a[i]);
  }
  if (n % 2) ans.push_back(a[n / 2]);
  for (int i = 0; i < n; i++) {
    printf("%d ", ans.back());
    ans.pop_back();
  }
  printf("\n");
}
int main() {
  int t;
  scanf("%d", &t);
  while (t--) {
    solve();
  }
}
