import sys
input = lambda: sys.stdin.readline().rstrip()

#  -----------------------  #

def main():
  n, m = map(int, input().split())
  G = [[] for _ in range(n)]
  for _ in range(m):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    G[a].append(b)
    G[b].append(a)
  return 'Yes'


print('\n'.join(str(main()) for _ in range(int(input()))))