Hi,
If you’re using the built-in IdP capabilities of Auth0 (i.e. a database connection) or AD/LDAP then you may be able to use the Resource Owner Password Grant. This allows you to submit a username / password pair in an authorisation request and receive an access token and (optionally) a refresh token in return.
However, if you need to support social IdPs or any other type of connection which doesn’t accept a username / password pair (most social IdPs don’t) you will have to use a different approach - perhaps automating the authorisation using something like Selenium or doing an authorisation manually and obtaining a refresh token which never expires and which can be used directly in your tests (along with a client credential) to get access tokens indefinitely.