#include <bits/stdc++.h>
using namespace std;
#define ll                long long int
#define fi                first
#define se                second
#define pb                push_back
#define rep(i,a,n)        for(ll i = a;i < n;i++)
#define vec               vector<ll>
#define read(v)           vec v(n,0); rep(i,0,n) {cin>>v[i];}
#define pairs             pair<int,int>
#define mpp               make_pair(a,b)
#define write(a,n)        rep(i,0,n) {cout<<a[i]<<" ";}cout<<endl;
#define all(v)            v.begin(),v.end()
#define srt(v)            sort(v.rbegin(),v.rend())
#define scn(a)            cin>>a
#define nl                endl
#define watch(x)          cout << (#x) << " is " << (x) << endl
#define gcd(a,b)          __gcd(a,b)
#define bitcount(n)       __builtin_popcount(n)
#define IOS               ios_base::sync_with_stdio(false); cin.tie(NULL);
#define mod               1000000007

void solve()
{
	int n;
	cin >> n;
	vec a(n);
	map<int, int>mp;
	for (int i = 0; i < n; i++)
		cin >> a[i];
	vector<int>ans;
	for (int i = 0; i < n; i++)
	{
		if (mp.find(a[i]) == mp.end())
		{
			ans.push_back(a[i]);
			mp[a[i]] = 0;
		}
		else
			mp[a[i]]++;
	}
	sort(ans.begin(), ans.end());
	for (auto x : mp)
	{
		int p = x.se;
		while (p-- > 0)
			ans.push_back(x.first);
	}
	write(ans, n);
}
int main()
{
#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	IOS
	ll t = 1;
	cin >> t;
	while (t-- > 0)
	{
		solve();
	}
#ifndef ONLINE_JUDGE
	cout << "\nTime Elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " sec\n";
#endif
}