#include <iostream>
#include <vector>
#include <cstring>
using namespace std;
vector<string> in;
const int MAX_N = 15;
int k;
int o[MAX_N][MAX_N], cache[MAX_N][1<<MAX_N];
int overlap2(string a, string b){
    if(a==b) return a.size();
    for(int i=0; i<a.size(); ++i){
        bool matched = true;
        int j;
        for(j=i; j<min(a.size(),i+b.size()); ++j){
            if(a[j] != b[j-i]) {
                matched = false;
                break;
            }
        }
        if(matched) return j-i;
    }
    return 0;
}
int overlap(int a, int b){
    int& ret = o[a][b];
    if(ret != -1) return ret;
    return ret = overlap2(in[a],in[b]);
}
int restore(int last, int used){
    if(used==(1<<k)-1) return 0;
    int& ret = cache[last][used];
    if(ret != -1) return ret;
    ret = 0;
    for(int i=0; i<in.size(); ++i)
        if((used & 1<<i)==0){
            int cand = overlap(last,i)+restore(i,used+(1<<i));
            ret = max(ret,cand);
        }
    return ret;
}
string reconstruct(int last, int used){
    if(used == (1<<k)-1) return "";
    for(int i=0; i<in.size(); ++i){
        if(used & (1<<i)) continue;
        int maxo = restore(i,used+(1<<i))+overlap(last,i);
        if(restore(last,used)==maxo)
            return in[i].substr(overlap(last,i)) + reconstruct(i,used+(1<<i));
    }
    return "";
}

int main(){
    int c;
    scanf("%d", &c);
    while(c--){
        in = vector<string>();
        memset(cache, -1, sizeof(cache));
        memset(o, -1, sizeof(o));
        scanf("%d", &k);
        for(int i=0; i<k; ++i){
            string s;
            cin >> s;
            bool insert = true;
            for(int j=0;j<in.size();++j){
                if(overlap2(in[j],s)==s.size()) insert = false;
                else if(overlap2(s,in[j])==in[j].size()){
                    in[j] = s;
                    insert = false;
                    break;
                }
            }
            if(insert) in.push_back(s);
        }
        int index=0,length=0;
        for(int i=0;i<in.size();++i)
            if(length < restore(i,1<<i)){
                length = restore(i,1<<i);
                index = i;
            }
        string result = in[index] + reconstruct(index,1<<index);
        printf("%s", result.c_str());
    }
    return 0;
}