Generalize storage mocking.
Improve test case name.
Remove handling of incomplete JSON.

Newer jsx only handles incomplete JSON optionally (an option which we do not
use right now).
Update alignment.
Test storage errors in oauth1_authorization_request module.
Test storage errors in oauth1_authorizations module.
Test callback not found in storage.
Leave TODO note to handle parsing errors.
Test storage errors for oauth1_credentials module.
Fix missing error case in oauth1_credentials module.
Test expiry in oauth1_credentials module.