#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long n, i, l, r;
    vector<long long> v;
    cin >> n;
    long long A[n];
    for (i = 0; i < n; i++) cin >> A[i];
    sort(A, A + n);
    if (n % 2 == 0) {
      r = n / 2;
      l = n / 2 - 1;
    } else {
      v.push_back(A[n / 2]);
      r = n / 2 + 1;
      l = n / 2 - 1;
    }
    while (r < n && l >= 0) {
      v.push_back(A[l]);
      v.push_back(A[r]);
      l--;
      r++;
    }
    for (i = 0; i < n; i++) cout << v[i] << " ";
    cout << "\n";
  }
}
