#include <bits/stdc++.h>
using namespace std;
template <class T, class T1>
int chkmin(T &x, const T1 &y) {
  return x > y ? x = y, 1 : 0;
}
template <class T, class T1>
int chkmax(T &x, const T1 &y) {
  return x < y ? x = y, 1 : 0;
}
const int MAXN = (1 << 20);
bool isPrime(long long n) {
  for (long long i = 2; i <= sqrt(n); i++) {
    if (n % i == 0) return false;
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long T = 1;
  cin >> T;
  for (long long t = 0; t < T; t++) {
    long long n;
    cin >> n;
    long long arr[n];
    for (long long i = 0; i < n; ++i) {
      cin >> arr[i];
    }
    sort(arr, arr + n);
    if (n % 2 == 1) {
      cout << arr[n / 2] << " ";
    }
    for (long long i = n / 2 - 1; i >= 0; i--) {
      cout << arr[n - i - 1] << " " << arr[i] << " ";
    }
    cout << '\n';
  }
  return 0;
}
