Rspec not responsive or working as intended?

Solved all problems correctly and thus rspec stops working and I need to use ctrl+c to escape. Is that working as intended?

No, you might have an infinite loop.

That’s strange, this works with repl.

Am I doing the syntax for a custom modulo wrong for Ruby? I basically just did this off memorization of what I did in JS for interview-prep.

Check the spec file and see what test cases that method is given. Maybe a certain input causes a loop?