#include<bits/stdc++.h>

#define endl '\n'
#define pii pair<int, int>
#define int long long
#define ld long double
#define ull unsigned long long

using namespace std;

const int mod=1e9+7,M=2000010,Mlog=22;

vector<ull>B;
void insert(ull x){
    for(auto b:B){
        x=min(x,b^x);
    }
    for(auto &b:B){
        b=min(b,b^x);
    }
    if(x){
        B.push_back(x);
    }
}

void solve(){
    int n;
    cin>>n;

    vector<int>a(n+1);
    B.clear();
    for(int i=1;i<=n;i++){
        cin>>a[i];
        insert(a[i]);
    }

    int ans=0;
    for(int x:B){
        ans^=x;
    }

    cout<<ans<<endl;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int t;
    cin>>t;

    while(t--){
        solve();
    }



    return 0;
}