/* -*- coding: utf-8 -*-
 *
 * 3560.cc:  No.3560 Giant Salamander - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_M = 200000;

/* typedef */

/* global variables */

int as[MAX_M], bs[MAX_M];

/* subroutines */

int check(int n, int m, int d) {
  int di = d;
  for (int i = 0; i < m; i++) {
    if (di + 1 > bs[i]) return -1;
    int i1 = (i + 1) % m;
    int a1 = (i1 > 0) ? as[i1] : as[i1] + n;
    di = (a1 - as[i] - 1) - (bs[i] - (di + 1));
    if (di < 0) return 1;
  }
  return 0;
}

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n, m;
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; i++) scanf("%d%d", as + i, bs + i), as[i]--;

    bool ok = true;
    for (int i = 0; ok && i < m; i++) {
      int i0 = (i + m - 1) % m, i1 = (i + 1) % m;
      int a0 = (as[i0] < as[i]) ? as[i0] : as[i0] - n;
      int a1 = (as[i] < as[i1]) ? as[i1] : as[i1] + n;

      ok =
	((a1 - as[i] + 1 <= bs[i] + bs[i1]) &&
	 (a1 - a0 - 1 >= bs[i]));
    }
    if (! ok) { puts("No"); continue; }

    int d0 = 0, d1 = min(as[0] + n - as[m - 1], bs[0] - 1);
    if (check(n, m, d0) == 0 || check(n, m, d1) == 0) {
      puts("Yes"); continue;
    }

    while (d0 + 1 < d1) {
      int d = (d0 + d1) / 2;
      int c = check(n, m, d);
      if (d == 0) break;
      if (c < 0) d0 = d;
      else d1 = d;
    }

    if (d0 + 1 < d1) puts("Yes");
    else puts("No");
  }

  return 0;
}