#include <bits/stdc++.h>
using namespace std;
template <typename T>
istream &operator>>(istream &is, vector<T> &arr);
template <typename T>
ostream &operator<<(ostream &os, vector<T> &arr);
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &p);
template <typename T>
istream &operator>>(istream &is, vector<T> &arr) {
  typename vector<T>::iterator a;
  for (a = arr.begin(); a != arr.end(); a++) {
    is >> *a;
  }
  return is;
}
template <typename T>
ostream &operator<<(ostream &os, vector<T> &arr) {
  typename vector<T>::iterator a;
  for (a = arr.begin(); a != arr.end(); a++) {
    os << *a << " ";
  }
  os << endl;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &p) {
  os << p.first << " " << p.second << '\n';
  return os;
}
long long INF = 1e18 + 5;
long long MOD = 1e9 + 7;
long long mul(long long a, long long b, long long md = MOD) {
  return (a % md * b % md) % md;
}
long long add(long long a, long long b, long long md = MOD) {
  return (a % md + b % md) % md;
}
bool valid(int i, int j, int n, int m) {
  return i >= 0 && i < n && j >= 0 && j < m;
}
vector<pair<int, int>> dirs = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
long long binPow(long long x, long long y) {
  int ans = 1;
  while (y > 0) {
    if (y % 2 == 1) ans = mul(ans, x);
    x = mul(x, x);
    y /= 2;
  }
  return ans;
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> a(n);
    cin >> a;
    sort(a.begin(), a.end());
    stack<int> st;
    int l = 0, r = n - 1;
    bool who = false;
    while (l <= r) {
      if (who) {
        st.push(a[l]);
        l++;
      } else {
        st.push(a[r]);
        r--;
      }
      who ^= 1;
    }
    while (!st.empty()) {
      cout << st.top() << ' ';
      st.pop();
    }
    cout << endl;
  }
}
