#include <bits/stdc++.h>
using namespace std;
double eps = 0.05;
long long mod = 1e9 + 7;
const int INF = 0x3f3f3f3f, inf = 0x3f3f3f3f;
const int MAXN = 2e3 + 10;
const double PI = acos(-1.0);
const int N = 1e6 + 7;
long long a[N];
struct node {
  long long x;
  bool operator<(node &p) { return abs(x - p.x); }
} p[N];
int main() {
  int t;
  scanf("%d", &t);
  while (t--) {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
      scanf("%lld", &a[i]);
    }
    sort(a, a + n);
    if (n % 2) {
      printf("%lld", a[n / 2]);
      for (int i = 1; i <= n / 2; i++) {
        printf(" %lld %lld", a[n / 2 - i], a[n / 2 + i]);
      }
    } else {
      printf("%lld %lld", a[n / 2 - 1], a[n / 2]);
      for (int i = 1; i < n / 2; i++) {
        printf(" %lld %lld", a[n / 2 - 1 - i], a[n / 2 + i]);
      }
    }
    printf("\n");
  }
  return 0;
}
