Question about school changing assignment (1 Viewer)

[Karldahemster]

Our year had a Physics assignment given to us about 5 weeks ago (due 3 weeks time today). Due to half yearlies coming up in the next few weeks, I wanted to get it out of the way so I finished it off last week. However, in today's lesson we were told that they had changed the assignment to an in class exam in 2 weeks time. Since I have spent all this time completing the assignment along with many others, this was extremely frustrating.

My question is if this is even allowed to be done, expecially after already having the assignment for 5 weeks. What should I do about this?

Thanks