put somebody/something through their/its paces
put somebody/something through their/its ˈpacestest somebody’s/something’s ability to do something by making them/it show how well they/it can actually perform certain actions, tasks, etc: We watched the trainer putting the police dog through its paces. ♢ They’re putting the new machinery through its paces.
These expressions refer to judging the performance of a horse before deciding to buy it.
put (someone) through (someone's) paces
To cause to demonstrate ability or skill; test: The drama coach put her students through their paces before the first performance.