#include <bits/stdc++.h>

using namespace std;
ifstream fin("zvon.in");
ofstream fout("zvon.out");
const int NMAX = 100005;
vector < int> G[NMAX];
bitset < NMAX > B;
int v[NMAX];
int dfs(int nod){
    int mx = 0;
    B[nod] = 1;
    for(int i = 0; i < G[nod].size(); i++){
        if(v[G[nod][i]] == 0  && B[G[nod][i]] == 0){
            int t = dfs(G[nod][i]);
            if(t > mx)
                mx = t;
            v[nod]++;
        }
    }
    return max(mx + 1,v[nod]);
}
int main()
{
    int n,t,x,y;
    fin >> t;
    for(int i = 1; i <= t; i++){
        fin >> n;
        for(int j  = 1; j <= n - 1; j++){
            fin >> x >> y;
            G[x].push_back(y);
            G[y].push_back(x);
        }
        for(int j  = 1; j <= n; j++)
            sort(G[j].begin(),G[j].end());
        if(n == 1)
            fout << 0 << "\n";
        else
            fout << dfs(1) << "\n";
        for(int j  = 1; j <= n; j++){
            G[j].clear();
            v[j] = 0;
            B[j] = 0;
        }

    }
    return 0;
}