Hi @kushankurxd
Welcome to the Auth0 Community!
I believe that you can implement an automated system for testing cases, using a hardcoded OTP, via Passwordless Authentication with Email and Configure a Custom Email Provider.
This will require a custom script that would call the Auth0 API endpoint to have a code sent to the specified email address, then access the inbox of that address to retrieve the code and use it to complete the authentication process.
Hope this helps!
Gerald