#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 5;
const int mod = 1e9 + 7;
int a[maxn], vis[maxn];
int solve() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  sort(a, a + n);
  int mid = n / 2;
  printf("%d ", a[mid]);
  if (n & 1)
    for (int i = 1; i < mid + 1; ++i) printf("%d %d ", a[mid - i], a[mid + i]);
  else {
    for (int i = 1; i < mid; ++i) printf("%d %d ", a[mid - i], a[mid + i]);
    printf("%d", a[0]);
  }
  return printf("\n");
}
int main() {
  int t;
  for (int i = 0; i < 1e5; ++i) t = i * i, t = sqrt(i), t = pow(2, i);
  int _;
  scanf("%d", &_);
  while (_--) solve();
}
