#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int t;
  cin >> t;
  while (t--) {
    long long int n, input;
    vector<long long int> v;
    cin >> n;
    for (auto i = 0; i < n; i++) {
      cin >> input;
      v.push_back(input);
    }
    sort(v.begin(), v.end());
    vector<long long int> result;
    for (auto i = 0; i < n / 2; i++) {
      result.push_back(v[n - i - 1]);
      result.push_back(v[i]);
    }
    if (n % 2) {
      result.push_back(v[n / 2]);
    }
    reverse(result.begin(), result.end());
    for (auto i = 0; i < n; i++) cout << result[i] << " ";
    cout << endl;
  }
  return 0;
}
