#include <bits/stdc++.h>
using namespace std;
long long a[100005];
long long x = -2e9, ma = 0;
bool cmp(long long a, long long b) { return abs(a - b) < abs(b - a); }
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) {
      cin >> a[i];
    }
    sort(a + 1, a + 1 + n);
    if (n & 1) {
      cout << a[n / 2 + 1] << " ";
      int i = n / 2, j = n / 2 + 2;
      for (int num = 1; num < n; num++) {
        if (num & 1)
          cout << a[i] << " ", i--;
        else
          cout << a[j] << " ", j++;
      }
    } else {
      cout << a[n / 2] << " ";
      int i = n / 2 - 1, j = n / 2 + 1;
      for (int num = 1; num < n; num++) {
        if (num % 2 == 0)
          cout << a[i] << " ", i--;
        else
          cout << a[j] << " ", j++;
      }
    }
    cout << endl;
  }
  return 0;
}
