Chore: Update rspec style tests from `should` to `expect`

[marcosdemelo]

@annacruz about the RSpec files at this diff main...asseinfo:ofx:master, you think interesting that create a PR to apply this changes?

[annacruz]

hey @marcosdemelo seems that those changes are needed. Can you open the PR? I just want to check also with my maintenance branch and with some local changes that I have.

(I could open, but I think it's better if you do so).