#include <bits/stdc++.h>
using namespace std;
long long min(long long a, long long b) { return (a < b) ? a : b; }
long long ds(long long x) {
  long long X = x;
  long long sum = 0;
  while (X > 0) {
    sum += X % 10;
    X /= 10;
  }
  return sum;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    vector<long long> a(n, 0);
    for (long long i = 0; i < n; i++) cin >> a[i];
    sort(a.begin(), a.end());
    long long f = 0, l = n - 1;
    vector<long long> ans;
    for (long long i = 0; i < n && l >= f; i++) {
      if (i % 2 == 0) {
        ans.push_back(a[l]);
        l--;
      } else {
        ans.push_back(a[f]);
        f++;
      }
    }
    for (long long i = ans.size() - 1; i >= 0; i--) cout << ans[i] << ' ';
    cout << endl;
  }
  return 0;
}
