Tests are explicitly mentioned in the list of works make for hire, but it's also within the scope of employment, so it's double counted.
> If a work is made for hire, the employer...is the initial owner of the copyright unless both parties involved have signed a written agreement to the contrary.
The school almost certainly does.
https://www.copyright.gov/circs/circ09.pdf
Tests are explicitly mentioned in the list of works make for hire, but it's also within the scope of employment, so it's double counted.
> If a work is made for hire, the employer...is the initial owner of the copyright unless both parties involved have signed a written agreement to the contrary.