#include<bits/stdc++.h>
using namespace std;
#define     ll              long long
#define     ld              long double
#define     precise         fixed<<setprecision(10)
#define     mp              make_pair
#define     pb              push_back
#define     ub              upper_bound
#define     lb              lower_bound
#define     t()             int t;cin>>t;
#define     pll             pair<ll,ll>
#define     vl              vector<ll>
#define     vll             vector< pll >  
#define     fast            ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define     ff              first
#define     ss              second
int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1}; 
int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};

void solve()
{
	int n;
	cin>>n;
	
	vl a(n,0);
	for(int i=0; i<n; i++)	cin>>a[i];
	
	map<int,int> mp;
	for(int i=0; i<n; i++)
	{
		mp[a[i]]++;
	}
	
//	for(auto i:mp)
//		cout<<i.first<<" "<<i.second<<endl;
	
	vl b;
	for(int i=0; i<n; i++)
	{
		//cout<<(mp.find(i) != mp.end())<<" "<<i<<endl;
		if(mp.find(i) != mp.end())
		{
			mp[i]--;
			b.pb(i);	
		}
		else
			break;
	}
	
	for(auto i:mp)
	{
		int val = i.ff;
		int num = i.ss;
		
		while(num>0)
		{
			b.pb(val);
			num--;
		}
	}
	
	for(auto i:b)
		cout<<i<<" ";
	cout<<endl;
}

int main()
{
	fast;
	t();
	
	while(t--)
	{
		solve();		
	}
	return 0;
}
