How to test oauth flow for google api? Do dummy tokens exist?

currently I have a bunch of functions that I wrote such as

def get_user_info(access_token):
    ...

def refresh_tokens(client_id, client_secret, refresh_token):
    ...

def create_tokens(client_id, auth_code):
    ...

I need a way of testing them automatically - using unittest.

Does the google API supply dummy authorization_code, access_code, refresh_code? For testing these 3rd party functions based off their rest api?