#include <iostream>
#include <stdio.h>
#include <iomanip>
#include <algorithm>
#include <cmath>
using namespace std;
const int N=200000+1;
const double INF=1e100;
struct Point{
double x,y;
bool flag;
};
Point m[N+1];
int tmp[N+1];
double dis(Point p1,Point p2)
{
return sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y));
}
double minL(double l1,double l2)
{
return l1<=l2?l1:l2;
}
bool cmpy(int a,int b)
{
return m[a].y<m[b].y;
}
bool cmpx(Point a,Point b)
{
return a.x<b.x;
}
double getMinLen(Point *s,int left,int right)
{
double rs=INF;
if(left == right)
return rs;
if(left+1 == right)
{
if(s[left].flag == s[right].flag)
return rs;
return dis(s[left],s[right]);
}
int mid=(left+right)>>1;
rs=getMinLen(s,left,mid);
rs=minL(rs,getMinLen(s,mid+1,right));//rs现在是两边中最点值了
int i,j,num=0;
for(i=left;i<=right;++i)
{
if(fabs(s[i].x-s[mid].x)<=rs)//过滤掉不可能是最近点对的点
tmp[num++]=i;
}
sort(tmp,tmp+num,cmpy);//按y坐标排序，减少比较次数
double d=INF;
for(i=0;i<num;++i)
{
for(j=i+1;j<num;++j)
{
if(fabs(s[tmp[i]].y-s[tmp[j]].y)>=rs)//i，j两点的y坐标已经大于rs,不需要在遍历了
break;
if(s[tmp[i]].flag!=s[tmp[j]].flag && (d=dis(s[tmp[i]],s[tmp[j]]))<rs)
rs=d;
}
}
//  cout<<left<<" "<<right<<" "<<rs<<endl;
return rs;
}
int main()
{
int t,n,i;
scanf("%d",&t);
while(t--)
{
scanf("%d",&n);
for(i=0;i<n;++i)
{
scanf("%lf%lf",&m[i].x,&m[i].y);
m[i].flag=0;
}
for(i=0;i<n;++i)
{
scanf("%lf%lf",&m[i+n].x,&m[i+n].y);
m[i+n].flag=1;
}
n<<=1;
sort(m,m+n,cmpx);
double ans=getMinLen(m,0,n-1);
cout<<setiosflags(ios::fixed)<<setprecision(3)<<ans<<endl;
}
return 0;
}