altered spec to test for unique_id

fixes SIS-175

Change-Id: I694df751ce8349bf2ac6c79b6c1f2c0b4010c6ab
Reviewed-on: https://gerrit.instructure.com/30397
Reviewed-by: Bryan Madsen <bryan@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>
Tested-by: Bryan Madsen <bryan@instructure.com>