how to mock an external function in ezyme or jest testing

// Component.js

render () {
const isEventAccessible = checkAccess(area);
if(isEventAccessible ){
  return(<div>No access</div);
}
return (<div>Acess</div>);

//checkAccess.js 

export const checkAccess = (a) => {
if(a==1){
  return true;
}
else{
  return false;  
}

}

I want to create two snapshots one for No Access view & one for Access but i can't pass checkAccess function in props how can i mock this function please help..????