#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pair<int,int>>
#define vll vector<pair<ll,ll>>
#define vvi vector<vector<int>>
#define vvl vector<vector<ll>>
#define vvii vector<vector<pair<int,int>>>
#define vvll vector<vector<pair<ll,ll>>>
#define vst vector<string>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define mkunique(x) sort(all(x));(x).erase(unique(all(x)),(x).end())
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=15<<26;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int Q;cin>>Q;
    while(Q--){
        ll N,M;cin>>N>>M;
        vl A(M),B(M);
        for(int i=0;i<M;i++){
            cin>>A[i]>>B[i];A[i]--;
        }
        if(M==1){
            cout<<"Yes\n";
            continue;
        }
        ll ad=N-1-A.back();
        for(int i=0;i<M;i++){
            A[i]+=ad;
        }
        A.pb(A[0]+N);
        B.pb(B[0]);
        
        ll L=0,R=A[0];
        ll sum=0;
        bool ok=true;
        for(int i=0;i<M;i++){
            ll l=A[i]-B[i]+1,r=A[i];
            if(i==0){
                chmax(l,0LL);
            }else{
                chmax(l,A[i-1]+1);
            }
            chmin(r,A[i+1]-B[i+1]);
            l-=sum;r-=sum;
            //cout<<l<<" "<<r<<"\n";
            if(l>r) ok=false;
            chmax(L,l);
            chmin(R,r);
            sum+=B[i];
        }
        if(L<=R&&ok) cout<<"Yes\n";
        else cout<<"No\n";
    }
}