var
x,y:array[0..1,0..100000]of longint;
i,n,m,t,k:longint;
ans,ans0,max:int64;

procedure suan;
var
a,b,a0,b0,i:longint;
max,tmp:int64;
begin
    a:=random(n)+1;
    b:=0;
    repeat
        a0:=a;b0:=b; max:=0;
        for i:=1 to m do begin
            tmp:=sqr(x[0,a]-x[1,i])+sqr(y[0,a]-y[1,i]);
            if tmp>max then begin
                max:=tmp;b:=i;
            end;
        end;
        max:=0;
        for i:=1 to n do begin
            tmp:=sqr(x[0,i]-x[1,b])+sqr(y[0,i]-y[1,b]);
            if tmp>max then begin
                max:=tmp;a:=i;
            end;
        end;
    until (a=a0)and(b=b0);
    ans:=max;
end;

begin
    assign(input,'faraway.in');reset(input);
    assign(output,'faraway.out');rewrite(output);
    randomize;
    read(t);
    for k:=1 to t do begin
        read(n,m);ans:=0;ans0:=-1;
        for i:=1 to n do read(x[0,i],y[0,i]);
        for i:=1 to m do read(x[1,i],y[1,i]);
        max:=-1;
        for i:=1 to 50 do begin
            ans:=0;ans0:=-1;
            while ans<>ans0 do begin
                if ans>ans0 then ans0:=ans;
                suan;
            end;
            if ans>max then max:=ans;
        end;
        writeln(extended(sqrt(max)):0:3);
    end;
    close(input);close(output);
end.