Bedtime paradox 😁

Awww shit! This is fucking with me.

Guess you test it the old fashioned way :p

Or the very base components at least.
Then the rest progressively use the components to test with, as they increasingly become available :p

simple use it to test itself

Use another test framework... lol😉

Paradox because even if you used a different testing framework then the question applies to that framework too And the next and ... But the answer is you use lots of traditional if-then statements or a functional approach 👍

two words... infinite recursion.... or try to divide by zero and see the whole universe implode at the start of Google's first ancient server.