You can find them in the SMART report, this section:
SMART Extended Self-test Log Version: 1 (1 sectors)
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 3966 -
That one passed, a failed test usually appears as "Completed: read failure" and an interrupted one as "Interrupted: host reset", also make sure disk spin down is disable, depending on the Unraid version it may interrupt the test.