#include <bits/stdc++.h>
using namespace std;

int main() {
	int T;
	cin >> T;
	while (T --> 0) {
		int n;
		cin >> n;
		vector<int> a(n);
		for (int i = 0; i < n; ++i) cin >> a[i];
		sort(a.begin(), a.end());
		vector<int> b;
		for (int i = 0; i < n; i++) {
		    if (i == 0 || a[i] != a[i - 1]) {
		        b.emplace_back(a[i]);
		    }
		}
		for (int i = 0; i < n; i++) {
		    if (i > 0 && a[i] == a[i - 1]) {
		        b.emplace_back(a[i]);
		    }
		}
		for (auto x : b) cout << x << ' ';
		cout << '\n';
	}
	return 0;
}