#include<cstdio>

typedef long long LL;

const int maxn =1e5+5;
const int log2maxn =60;

int n;
LL p[maxn];
LL a[maxn]; 

void standing_by()
{
	int i,j;
	LL k;
	for(i=0;i<log2maxn;i++)
		p[i]=0;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%lld",&a[i]);
		if (a[i]==0) continue;
		k=a[i];
		for(j=log2maxn-1;j>=0;j--)
			if ((k>>j)&1)
			{
				if (p[j]==0)
				{
					p[j]=k;
					break;
				}else {
					k^=p[j];
				}
			}
	}
}

void complete()
{
	LL ans=0;
	int i;
	for(i=log2maxn-1;i>=0;i--)
		if (((ans>>i)&1)==0) ans^=p[i];
	
	printf("%lld\n",ans);
}

int main()
{
	int t;
	scanf("%d",&t);
	for(;t;t--)
	{
		standing_by();
		complete();
	}
	return 0;
}