#include <bits/stdc++.h>
using namespace std;
int t, n, a[100005], f[100005];
map<int, int> mapa;
int main() {
  scanf("%d", &t);
  for (int i = 0; i < t; i++) {
    scanf("%d", &n);
    for (int j = 0; j < n; j++) {
      scanf("%d", &a[j]);
    }
    sort(a, a + n);
    int c = 0;
    bool x = false;
    for (int i = n - 1; i >= 0; i--) {
      if (!x)
        f[i] = a[n - 1 - c];
      else
        f[i] = a[c], c++;
      x = !x;
    }
    for (int i = 0; i < n; i++) {
      printf("%d ", f[i]);
    }
    printf("\n");
  }
}
