#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
void OFAST() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr), cout.tie(nullptr);
}
int main() {
  double timing = clock();
  OFAST();
  int tes;
  cin >> tes;
  int n, l, r;
  while (tes--) {
    cin >> n;
    vector<int> a(n);
    for (int i = (0), _b = (n); i < _b; ++i) cin >> a[i];
    sort(a.begin(), a.end());
    l = ((int(a.size())) - 1) / 2;
    r = l + 1;
    do {
      cout << a[l] << ' ';
      if (r == (int(a.size()))) break;
      cout << a[r] << ' ';
      --l;
      ++r;
    } while (l != -1);
    cout << endl;
  }
  cerr << "\n\nREAL TIME: " << fixed << setprecision(4)
       << (clock() - timing) / CLOCKS_PER_SEC << endl;
}
