Please read these two blog posts:
I would not recommend doing what you outline. More than likely SRM will be out of sync and it will quite likely require you to rebuild it. Regardless it isn't supported.
I highly recommend using the test functionality built into SRM. If the SRA supports it, it can be done with the sites disconnected.
I am surprised there isn't something that can be done to keep SRM in sync after a site disconnect test like this, based on numbers of forum posts on this topic and a customer request to fully test DR but leave all production datacenter systems in exact state. The array replication can be put back in place easily enough with vendors like NetApp. But I think there needs to be something in SRM like the test RP cleanup task where you could clean up a real RP and have SRM understand that a recovery plan was run but it was rolled back when the 2 SRM servers re-communicate.
It is something we're looking into doing. I can't provide a timeframe but want to be clear that it is being evaluated/investigated for a future release