#include <bits/stdc++.h>
using namespace std;
int a[100005];
vector<int> v;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n;
    v.clear();
    cin >> n;
    for (int i = 1; i <= n; i++) {
      cin >> a[i];
    }
    sort(a + 1, a + n + 1);
    int j = 0;
    if (n % 2 == 0) {
      for (int i = 1; i <= n / 2; i++) {
        v.push_back(a[i]);
        v.push_back(a[n - j]);
        j++;
      }
      for (int i = v.size() - 1; i >= 0; i--) {
        cout << v[i] << " ";
      }
    } else if (n % 2 == 1) {
      j = 0;
      for (int i = 1; i <= n / 2; i++) {
        v.push_back(a[n - j]);
        v.push_back(a[i]);
        j++;
      }
      cout << a[(n / 2) + 1] << " ";
      for (int i = v.size() - 1; i >= 0; i--) {
        cout << v[i] << " ";
      }
    }
    cout << endl;
  }
  return 0;
}
