Wiktionary
probationary period
n. A period during which a new employee is tried for capability of doing his or her job.
Usage examples of "probationary period".
Traditionally, this meant a lengthy probationary period as a classless hanger-on.
Throughout the long probationary period, they were therefore to have only their natural endowment to see them through the problems they encountered.
That if she changes her mind during this 'probationary period' we will welcome her home and rejoice.
Since we have a ten-year probationary period before humans will be allowed to travel to other worlds, except the patterner, that is, no other human will see other planets for at least that long, and she’.
She gets a six-month probationary period before they decide if she keeps her command.