#include <bits/stdc++.h>
using namespace std;
const long long maxn = 1e6 + 10;
const long long inf = 0x3f3f3f3f3f3f;
const long long mod = 1e9 + 7;
long long qsm(long long a, long long b, long long mod) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = ans * a % mod;
    b /= 2;
    a = a * a % mod;
  }
  return ans;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long T, n, m;
long long a1[maxn], a2[maxn], a3[maxn];
vector<int> q[maxn];
int main() {
  cin >> T;
  while (T--) {
    cin >> n;
    for (int i = 0; i < n; i++) {
      cin >> a1[i];
    }
    sort(a1, a1 + n);
    int left = n / 2 - 1 + n % 2;
    int right = left + 1;
    int now = 0;
    while (now < n) {
      if (now % 2 == 0)
        cout << a1[left--] << " ";
      else
        cout << a1[right++] << " ";
      now++;
    }
    cout << endl;
  }
  return 0;
}
