#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void amin(T &x, const T &y) {
  if (y < x) x = y;
}
template <class T>
inline void amax(T &x, const T &y) {
  if (x < y) x = y;
}
using ll = signed long long;
using PII = pair<int, int>;
using VI = vector<int>;
using VVI = vector<VI>;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int MAXN = 700;
const int N = 100005;
int _;
ll n;
int a[N], b[N];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  for (scanf("%d", &_); _; _--) {
    scanf("%d", &n);
    for (int i = (0); i < (n); i++) scanf("%d", a + i);
    sort(a, a + n);
    for (int i = n - 1, l = 0, r = n - 1; i >= 0; i--) {
      if (i & 1)
        b[i] = a[l++];
      else
        b[i] = a[r--];
    }
    for (int i = (0); i < (n); i++) printf("%d%c", b[i], " \n"[i == n - 1]);
  }
  return 0;
}
