#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (!b) return a;
  return gcd(b, a % b);
}
long long power(long long x, long long y, long long p = 1e18) {
  long long result = 1;
  x %= p;
  while (y > 0) {
    if (y & 1) result = (result * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return result;
}
void solve() {
  long long n;
  cin >> n;
  vector<long long> a(n);
  for (long long i = 0; i < (long long)(n); ++i) cin >> a[i];
  sort((a).begin(), (a).end());
  bool foo = true;
  long long i = 0, j = n - 1;
  vector<long long> res;
  while (j >= i) {
    if (foo)
      res.emplace_back(a[j--]);
    else
      res.emplace_back(a[i++]);
    foo = !foo;
  }
  reverse((res).begin(), (res).end());
  for (auto x : res) cout << x << " ";
  cout << "\n";
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  long long x = 1;
  cin >> t;
  cout << fixed << setprecision(12);
  while (t--) {
    solve();
    x++;
  }
  cerr << "Time Taken : " << (float)clock() / CLOCKS_PER_SEC << " secs"
       << "\n";
}
