Thanks!

simple check (2.3ms)

1. test simple check (TestNegator)
   fixture:5
   Assertion with == failed
   code: make_negative(-42) == 42
   lhs: -42
   rhs: 42
   stacktrace:
   fixture:6

Test case make_negative(-42) == 42
is incorrect. broken.

Good amount / 1

Good is_integer(n)

Beautiful!

Above code returns false for typer.isNumber(1).

How did this pass the unit test?

This is consise but slow.

We only need to check if i is diveded by primes less than i,
but this code checks all the number including composite numbers.

i.e, we only need to check if 11 is divisible by 2, 3, 5, 7,
but above code checks 2,3,4,5,6,7,8,9,10.