#include <bits/stdc++.h>
const long long mod = 1000000007;
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int test;
  cin >> test;
  while (test--) {
    long long n;
    cin >> n;
    vector<long long> arr(n);
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
    }
    sort((arr).begin(), (arr).end());
    vector<long long> ans;
    long long i = 0, j = n - 1;
    while (i < j) {
      ans.push_back(arr[j]);
      ans.push_back(arr[i]);
      i++;
      j--;
    }
    if (i == j) ans.push_back(arr[i]);
    for (int i = n - 1; i >= 0; i--) {
      cout << ans[i] << " ";
    }
    cout << endl;
  }
}
