#include <bits/stdc++.h>
using namespace std;
string ans;
long long a[400000], b[400000];
long long n;
int main() {
  int t;
  cin >> t;
  while (t--) {
    cin >> n;
    for (int i = 1; i <= n; ++i) scanf("%lld", &a[i]);
    sort(a + 1, a + n + 1);
    int idx = n;
    int l = 1, r = n;
    while (l <= r) {
      b[idx] = a[r];
      b[idx - 1] = a[l];
      r--;
      l++;
      idx -= 2;
    }
    for (int i = 1; i <= n; ++i) printf("%lld ", b[i]);
    cout << endl;
  }
  return 0;
}
