#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e5 + 10;
int T, N;
int a[MAX];
int main() {
  scanf("%d", &T);
  while (T--) {
    scanf("%d", &N);
    for (int i = 1; i <= N; i++) scanf("%d", &a[i]);
    sort(a + 1, a + 1 + N);
    int l = (N + 1) / 2, r = (N + 1) / 2;
    printf("%d", a[l]);
    for (int i = 1; i < N; i++) {
      if (i & 1)
        printf(" %d", a[++r]);
      else
        printf(" %d", a[--l]);
    }
    printf("\n");
  }
  return 0;
}
