not true. i test if there is a bug on my table using my eyes and i do not observe any bugs. therefore, they must be absent

not true. i test if there is a bug on my table using my eyes and i do not observe any bugs. therefore, they must be absent
also some functions have small enough domains that you can exhaustively test them :p
i have seen people use it for functions that take a single 32-bit float as input but yeah