1
2 2
1 1
1 2
 1
1 3
3
1 2 3
 1
1 1
1000
1000
 1
2 2
2 2
2 2
 5
4 5
10 8 6 4
1 2 3 4 5
1 1
3
3
1 1
3
2
5 3
1000 2 2 2 3
3 1 5
5 5
1 2 3 4 5
1 2 3 4 5
 1
4 4
1 1 1 1
1 2 3 4
 1
2 3
1 1
1 2 3

YES
1 1
 YES
1 3
 YES
1 1000
 YES
1 2
 YES
1 4
YES
1 3
NO
YES
1 3
YES
1 1
 YES
1 1
 YES
1 1

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
const int inf = 1e9 / 2;
const int inf1 = 1e9;
const int simple = 1e9 + 7;
int32_t main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    long long a[n];
    for (int i = 0; i < n; ++i) {
      cin >> a[i];
    }
    sort(a, a + n);
    for (int i = 0; i < n - 1; ++i) {
      if (a[i] == a[i + 1]) {
        cout << a[i] << ' ' << a[i] << ' ';
        a[i] = 1e10;
        a[i + 1] = 1e10;
      }
    }
    for (int i = 0; i < n; ++i) {
      if (a[i] != 1e10 && a[i] > 0) {
        cout << a[i] << ' ';
        a[i] = 1e10;
      }
    }
    for (int i = 0; i < n; ++i) {
      if (a[i] != 1e10) {
        cout << a[i] << ' ';
      }
    }
    cout << '\n';
  }
}
