#include <bits/stdc++.h>
using namespace std;
inline void boost() {
  ios::sync_with_stdio(false);
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
}
template <typename T>
inline bool innrange(T lo, T hi, T val) {
  return val >= lo && hi >= val;
}
template <typename T>
inline bool inrange(T lo, T hi, T val) {
  return val > lo && hi > val;
}
static constexpr auto N = ((100ull) * 1024ull);
static constexpr auto MOD = 1000000007;
static constexpr auto INF = numeric_limits<int>::max();
static constexpr auto INFl = numeric_limits<long long>::max();
array<int, N> na;
array<pair<int, int>, N> da;
int main() {
  boost();
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    for (int ni = 0; ni < n; ni++) cin >> na[ni];
    sort(begin(na), begin(na) + n);
    vector<int> res;
    for (int ni = 0; ni <= n / 2; ni++) {
      if (n == (1 + 2 * ni)) {
        res.push_back(na[ni]);
      } else if (ni != n / 2) {
        res.push_back(na[n - ni - 1]);
        res.push_back(na[ni]);
      }
    }
    reverse(begin(res), end(res));
    for (auto i : res) cout << i << " ";
    cout << endl;
  }
  return 0;
}
