#include <bits/stdc++.h>
using namespace std;
bool compare(string &s1, string &s2) { return s1.size() < s2.size(); }
void yes() { cout << "YES" << endl; }
void no() { cout << "NO" << endl; }
int main(void) {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    long long int arr1[n + 2];
    long long int arr2[n + 2];
    for (long long int i = 0; i < n; i++) {
      cin >> arr1[i];
      arr2[i] = arr1[i];
    }
    sort(arr1, arr1 + n);
    long long int k;
    if (n % 2 == 0) {
      k = n / 2;
      for (long long int i = k - 1, j = k; j < n; j++, i--) {
        cout << arr1[i] << " " << arr1[j] << " ";
      }
    } else {
      k = (n / 2);
      cout << arr1[k] << " ";
      for (long long int i = k - 1, j = k + 1; j < n; j++, i--) {
        cout << arr1[i] << " " << arr1[j] << " ";
      }
    }
    cout << endl;
  }
  return 0;
}
