#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pair<int,int>>
#define vll vector<pair<ll,ll>>
#define vvi vector<vector<int>>
#define vvl vector<vector<ll>>
#define vvii vector<vector<pair<int,int>>>
#define vvll vector<vector<pair<ll,ll>>>
#define vst vector<string>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define mkunique(x) sort(all(x));(x).erase(unique(all(x)),(x).end())
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=15<<26;

ll solve(vl A){
    sort(all(A));
    ll N=si(A);
    if(N==1) return A[0];
    
    ll L=0,R=N+2;
    while(R-L>1){
        ll M=(L+R)/2;
        vl imo(M);
        imo[M-1]++;
        
        vl CN(M);
        ll rem=0;
        for(ll x:A){
            if(x>=M) rem++;
            else CN[x]++;
        }
        
        bool ok=true;
        for(ll i=M-1;i>=0;i--){
            if(i==0) CN[i]+=rem;
            
            ll can=min(imo[i],CN[i]);
            ll need=imo[i]-can;
            if(i==0&&need) ok=false;
            else{
                rem+=CN[i]-can;
                if(i) imo[i-1]+=need;
            }
            
            if(i) imo[i-1]+=imo[i];
        }
        
        if(ok) L=M;
        else R=M;
    }
    
    return L;
}
int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int Q;cin>>Q;
    while(Q--){
        ll N;cin>>N;
        vl A(N);
        for(int i=0;i<N;i++){
            cin>>A[i];
        }
        cout<<solve(A)<<"\n";
    }
}