#include <bits/stdc++.h>
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define SP << " " <<
#define fish signed
using namespace std;
mt19937 rnd(1209);
const int INF = 0x3f3f3f3f3f3f3f3f;
const int N = 1e5 + 10;
vector<pair<int, int>> g;
vector<int> e[N];
int fa[N], fa1[N], d[N];
int find(int x) {return fa[x] == x ? x : fa[x] = find(fa[x]);}
set<pair<int, int>> edge;
void dfs(int u, int f)
{
    fa1[u] = f; if(f) edge.insert({u, f});
    for(auto v : e[u]) if(v != f) dfs(v, u);
}
void solve()
{
    int n, m; cin >> n >> m;
    for(int i = 1; i <= n; i ++) fa[i] = i, d[i] = 0, e[i].clear();
    g.clear(); edge.clear();
    for(int i = 1; i <= m; i ++)
    {
        int u, v; cin >> u >> v;
        int fu = find(u), fv = find(v);
        if(fu != fv)
        {
            fa[fu] = fv;
            e[u].push_back(v), e[v].push_back(u);
            d[u] ++, d[v] ++;
        }
        else g.push_back({u, v});
    }
    int rt = 0;
    for(int i = 1; i <= n; i ++) if(d[i] > d[rt]) rt = i;
    dfs(rt, 0);
    for(int i = 1; i <= n; i ++) if(fa1[i] != rt) fa[i] = fa1[i]; else fa[i] = i;
    for(auto x : g)
    {
        if(d[rt] <= n / 2) break;
        int u = x.first, v = x.second;
        int fu = find(u), fv = find(v);
        if(fu == fv) continue;
        if(d[fu] > d[fv]) swap(fu, fv), swap(u, v);
        edge.erase({fv, rt});
        edge.insert({v, u});
        fa[fv] = fu;
        d[u] ++, d[v] ++, d[fv] --, d[rt] --;
    }
    rt = 0;
    for(int i = 1; i <= n; i ++) if(d[i] > d[rt]) rt = i;
    if(d[rt] <= n / 2)
    {
        cout << "Yes\n";
        assert(edge.size() <= n - 1);
        for(auto v : edge) cout << v.first SP v.second << "\n";
    }
    else cout << "No\n";
}
fish main()
{
    // freopen(".in", "r", stdin);
    // freopen(".out", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; cin >> t;
    while(t --) solve();
    return 0;
}