#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cstdlib>

#include<iostream>

#include<cmath>

#include<vector>

#include<queue>

#define inf 0x3f3f3f3f

#define MAX_V 10010

using namespace std;

typedef long long ll;

typedef pair<int,int>P;

struct edge{int to,cap,cost,rev;};

int V;

vector<edge>G[MAX_V];

int h[MAX_V],dist[MAX_V],prevv[MAX_V],preve[MAX_V];

void add_edge(int from,int to,int cap,int cost){

    G[from].push_back((edge){to,cap,cost,G[to].size()});

    G[to].push_back((edge){from,,-cost,G[from].size()-});

}

int min_cost_flow(int s,int t,int f){

    int res=;

    fill(h,h+V,);

    while(f>){

        priority_queue<P,vector<P>,greater<P> >que;

        fill(dist,dist+V+,inf);

        dist[s]=;

        que.push(P(,s));

        while(!que.empty()){

            P p=que.top();que.pop();

            int v=p.second;

            if(dist[v]<p.first) continue;

            for(int i=;i<G[v].size();i++){

                edge &e=G[v][i];

                if(e.cap>&&dist[e.to]>dist[v]+e.cost+h[v]-h[e.to]){

                    dist[e.to]=dist[v]+e.cost+h[v]-h[e.to];

                    prevv[e.to]=v;

                    preve[e.to]=i;

                    que.push(P(dist[e.to],e.to));

                }

            }

        }

        if(dist[t]==inf) return -;

        for(int v=;v<V;v++) h[v]+=dist[v];

        //增广

        int d=f;

        for(int v=t;v!=s;v=prevv[v]) d=min(d,G[prevv[v]][preve[v]].cap);

        f-=d;

        res+=d*h[t];

        for(int v=t;v!=s;v=prevv[v]){

            edge &e=G[prevv[v]][preve[v]];

            e.cap-=d;

            G[v][e.rev].cap+=d;

        }

    }

    return res;

}

int n,m,t1,t2,t3,t4;

int z[][];

int main(){

    int _;

    scanf("%d",&_);

    while(_--){

        memset(G,,sizeof G);

        scanf("%d%d",&n,&m);

        for(int i=;i<n;i++){

            for(int j=;j<m;j++){

                scanf("%d",&z[i][j]);

            }

        }

        int s=n+n*m,t=s+;

        V=t+;

        for(int i=;i<n;i++) add_edge(s,i,,);

        for(int j=;j<m;j++){

            for(int k=;k<n;k++){

                add_edge(n+j*n+k,t,,);

                for(int i=;i<n;i++){

                    add_edge(i,n+j*n+k,,(k+)*z[i][j]);

                }

            }

        }

        printf("%.6f\n",(double)min_cost_flow(s,t,n)/n);

    }

    return ;

}