#include <bits/stdc++.h>
using namespace std;
int n, t;
int a[300100];
int ans[300010];
int main() {
  scanf("%d", &t);
  while (t--) {
    int n;
    int cnt = 0;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", a + i);
    sort(a + 1, a + n + 1);
    for (int i = 1; i <= n; i++) {
      if (i == n - i + 1) {
        ans[++cnt] = a[i];
        break;
      }
      if (i > n - i + 1) break;
      ans[++cnt] = a[n - i + 1];
      ans[++cnt] = a[i];
    }
    for (int i = n; i > 0; i--) printf("%d ", ans[i]);
    cout << endl;
  }
  return 0;
}
