#include<bits/stdc++.h>
using namespace std;
int T;
int main(){
	cin>>T;
	for(int i=1;i<=T;i++){
		int n=0,m=0;
		cin>>n>>m;
		if(m==0||m==1){
			cout<<"Yes"<<endl;
			continue;
		}
		int p1=0,p2=0;
		long long d=0,x1=0,x2=0;
		bool flag=false;
		cin>>p1>>x1>>p2>>x2;
		if(p1<p2){
			d=(x2-x1)/(p2-p1);
			if((p2-p1)*d!=(x2-x1)){
				cout<<"No"<<endl;
				continue;
			}
		}
		else{
			d=(x1-x2)/(p1-p2);
			if((p1-p2)*d!=(x1-x2)){
				cout<<"No"<<endl;
				continue;
			}
		}
		for(int j=3;j<=m;j++){
			int p=0;
			long long x=0;
			cin>>p>>x;
			if(p<p1){
				if(x1!=x+(p1-p)*d){
					flag=true;
					cout<<"No"<<endl;
					break;
				}
			}
			else{
				if(x!=x1+(p-p1)*d){
					flag=true;
					cout<<"No"<<endl;
					break;
				}
			}
		}
		if(flag==false){
			cout<<"Yes"<<endl;
		}
	}
	return 0;
}

RT，不知道哪里写错了。