Can anyone confirm for me if SSSD supports authentication of users belonging to a trusted domain via an AD controller in the trusting domain?

ie. A user attempts to log in as fred@test1.example.com on a client machine running SSSD, where SSSD has joined a domain test2.example.com and there is a 2-way forest trust between both domains. Is this supported? I've been trying to do so and so far it hasn't been working.

For the record, my setup is:

AD controller domain test1: Windows server 2012 R2
AD controller domain test2: Windows server 2012 R2
Ubuntu 14.04 client running SSSD 1.12.5