#include<bits/stdc++.h>
#define int long long
using namespace std;
#define ll long long
#define ull unsigned long long
int n,m,sum;
const int N = 1e5 + 10;
const ull mask = std::chrono::steady_clock::now().time_since_epoch().count();
ull shift(ull x) {
  x ^= mask;
  x ^= x << 13;
  x ^= x >> 7;
  x ^= x << 17;
  x ^= mask;
  return x;
}
ull Hash[N];
struct Node{
	int a,b;
}a[N];
std::vector<int> edge[N];
//std::set<ull> trees;
int dep[N],fa[N];
bool mark[N];
bool Mark[N];
void dfs(int x){
	for(int u:edge[x]){
		if(u==fa[x])continue;
		fa[u]=x,dep[u]=dep[x]+1;
		dfs(u);
	}
}

void getHash(int x, int p) {
	Hash[x] = 1;
	for (int i : edge[x]) {
		if (i == p || mark[i])continue;
    	getHash(i, x);
    	Hash[x] += shift(Hash[i]);
	}
}
vector<ll>ans;
void Dfs(int x){
	Mark[x]=true;
	getHash(x,0);
	ans.push_back(Hash[x]);
	for(int i : edge[x]){
		if(Mark[i]||!mark[i])continue;
		Dfs(i);
	}
	Mark[x]=false;
}
int f[N];
int gf(int x){
	return f[x]=(x==f[x]?x:gf(f[x]));
}
bool check(){
	for(int i=0;i+1<ans.size();++i)
		if(ans[i]!=ans[i+1])return false;
	return true;
}
bool Check(){
	for(int i=0;i+2<ans.size();i+=2)
		if(ans[i]!=ans[i+2])return false;
	for(int i=1;i+2<ans.size();i+=2)
		if(ans[i]!=ans[i+2])return false;
	return true;
}
void solve(){
	cin>>n>>m;
	for(int i=1;i<=m;++i){
		cin>>a[i].a>>a[i].b;
	}
	if(m>n){
		cout<<"NO\n";
		return;
	}
	if(m==n-1){
		cout<<"YES\n";
		return;
	}
	for(int i=1;i<=n;++i)
		f[i]=i,mark[i]=false,edge[i].clear();
	int sa,sb,t;
	for(int i=1;i<=m;++i){
		int fx=gf(a[i].a),fy=gf(a[i].b);
		if(fx==fy){
			sa=a[i].a;
			t=sa;
			sb=a[i].b;
			continue;
		}
		f[fx]=fy;
		edge[a[i].a].push_back(a[i].b);
		edge[a[i].b].push_back(a[i].a);
	}
	mark[sa]=mark[sb]=true;
	dfs(1);
	if(dep[sa]<dep[sb])swap(sa,sb);
	while(dep[sa]>dep[sb]){
		sa=fa[sa];
		mark[sa]=true;
	}
	while(sa!=sb){
		mark[sa]=mark[sb]=true;
		sa=fa[sa],sb=fa[sb];
	}
	mark[sa]=true;
	ll now=0;
	ans.clear();
	Dfs(t);
	if(n&1)cout<<(check()?"YES\n":"NO\n");
	else cout<<(check()||Check()?"YES\n":"NO\n");
}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int T;
    cin>>T;
    while(T--)solve();
}