#include <bits/stdc++.h>
using namespace std;
const int NMAX = 1e5;
int v[NMAX + 5], ans[NMAX + 5];
inline void GenerateAnswer(int n) {
  int i, state = 1, st = 1, dr = n, dim = 0;
  sort(v + 1, v + n + 1);
  while (st <= dr) {
    if (st != dr) {
      if (state == 1)
        ans[++dim] = v[st], ans[++dim] = v[dr];
      else
        ans[++dim] = v[dr], ans[++dim] = v[st];
    } else
      ans[++dim] = v[st];
    ++st;
    --dr;
  }
}
int main() {
  int t, n, i, j;
  scanf("%d", &t);
  for (j = 1; j <= t; ++j) {
    scanf("%d", &n);
    for (i = 1; i <= n; ++i) scanf("%d", &v[i]);
    GenerateAnswer(n);
    for (i = n; i >= 1; --i) printf("%d ", ans[i]);
    printf("\n");
  }
  return 0;
}
