Obtain new access token when the current one expires

[vlad-ignatov]

Many tests might fail with unexpected 401 responses because the access token has expired while running the test. The client should be able to automatically obtain fresh token if needed.

P.S. The SMART server can be helpful in testing/fixing this because you can configure it to use one minute token lifetime.

[arscan]

Thanks @vlad-ignatov -- absolutely. We noticed this as well and is something that we are looking into solving generically, but requires us moving a few things around so we don't have to have tests that are concerned with API and content validation also need authorization-level logic in it. Thanks for opening an issue.

I love how you can configure the token lifetime in the SMART server. Extremely helpful!