[tialaramex]

I call unwrap a lot in unit tests where it feels obvious to me that this succeeds, so, if it doesn't that's a huge mistake and should definitely fail the test but I have no pre-existing description of what's wrong, it's just a big red flag that I'm wrong.

Fallible conversions that never fail in the tested scenario are an example - parsing "15/7" as a Rational is never going to fail, so unwrap(). Converting 0.125 into a Real is never going to fail, so unwrap(). In a doctest I would write at least the expect call, because in many contexts you should handle errors and this shows the reader what they ought to do, but in the unit test these errors should never happen, there's no value in extensive handling code for this case.