// MagicDark
#include <bits/stdc++.h>
#define debug cerr << "\33[32m[" << __LINE__ << "]\33[m "
#define SZ(x) ((int) x.size() - 1)
#define all(x) x.begin(), x.end()
#define ms(x, y) memset(x, y, sizeof x)
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
template <typename T> T& chkmax(T &x, T y) {return x = max(x, y);}
template <typename T> T& chkmin(T &x, T y) {return x = min(x, y);}
template <typename T> T& read(T &x) {
	x = 0; int f = 1; char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') f = - f;
	for (; isdigit(c); c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
	return x *= f;
}
const int N = 2e5 + 10;
int n, m, deg[N], fa[N], dd[N];
// vector <int> v[N];
pair <int, int> e[N];
int find(int x) {return x == fa[x] ? x : fa[x] = find(fa[x]);}
void zhk() {
	cin >> n >> m;
	F(i, 1, n) deg[i] = dd[i] = 0, fa[i] = i;
	F(i, 1, m) {
		cin >> e[i].first >> e[i].second;
		deg[e[i].first]++;
		deg[e[i].second]++;
		// int x, y; cin >> x >> y;
	}
	sort(e + 1, e + m + 1, [&] (pair <int, int> x, pair <int, int> y) {
		return deg[x.first] + deg[x.second] < deg[y.first] + deg[y.second];
	});
	vector <pair <int, int>> ans;
	F(i, 1, m) {
		int x = find(e[i].first), y = find(e[i].second);
		if (x == y) continue;
		ans.push_back(e[i]);
		fa[x] = y;
		dd[x]++, dd[y]++;
	}
	F(i, 1, n)
		if (dd[i] > n / 2) {
			cout << "No\n";
			return;
		}
	cout << "Yes\n";
	for (auto [a, b]: ans) cout << a << ' ' << b << '\n';
}
signed main() {
	ios::sync_with_stdio(0); // don't use puts
	cin.tie(0), cout.tie(0);
	int _ = 1;
	cin >> _;
	while (_--) zhk();
	return 0;
}
/* why?
*/