#include"testlib.h"

#include <set>
#include <utility>
#include <atcoder/dsu>

using ll = long long;
const ll Nmin = 2;
const ll Nmax = 60;
const ll Kmin = 2;
const ll Kmax = 210;

int main(){
    registerValidation();
    ll K = inf.readLong(Kmin, Kmax);
    inf.readEoln();
    for (ll i = 1; i <= K; i++){
        std::set<std::pair<ll, ll>> es;
        ll N = inf.readLong(Nmin, Nmax);
        inf.readSpace();
        ll M = inf.readLong(1LL, N*(N-1)/2);
        inf.readEoln();
        atcoder::dsu d(N);
        for (ll ii = 1; ii <= M; ii++){
            ll ui = inf.readLong(1LL, N);
            inf.readSpace();
            ll vi = inf.readLong(1LL, N);
            inf.readEoln();
            inf.ensuref(ui < vi, "ui < vi");
            inf.ensuref(!es.contains({ui, vi}), "edges are distinct");
            es.insert({ui, vi});
            ui--, vi--;
            d.merge(ui, vi);
        }
        inf.ensuref((ll)(d.groups().size()) == 1, "graph connected");
    }
    inf.readEof();
}