rational-numbers missing test case for negative rational exponent

[neduard]

The problem description states:

Exponentiation of a rational number r = a/b to a negative integer power n is r^n = (b^m)/(a^m), where m = |n|.

However this is not checked for in the tests.

As such, the tests pass even if the implementation does something like

def rational_exponentiation(r, n):
  return Fraction(r.a ** n, r.b ** n)

Would my understanding be correct? I'm happy to raise PR and add a test, just that I don't know how to generate UUID for it 😅

(thanks @angelikatyborska for suggesting raising an issue)

[ericbalawejder]

It appears that there are only two tests for this case and they both use a positive integer power. No negative integer power as you mentioned. It would seem valuable to create a test implementation for it.

Even though it is not stated in the problem description, there is also no test for taking a negative real number and raising it to a rational power.

Exponentiation of a real number x to a rational number r = a/b is x^(a/b) = root(x^a, b), where root(p, q) is the qth root of p.

If x were to be less than zero (negative), and r = a/b, where b is even, this would result in complex roots. If b is odd, it is ok to take the odd roots of negative numbers, as it preserves the sign. It may be a valuable lesson when implementing this particular method/function. Thoughts?

[petertseng]

Correct understanding. Adding a test for negative integer power would be good.

A UUID may be generated with any tool of your choice that generates version 4 UUIDs, even those that are available as a webpage on the internet.

For consideration of negative real numbers raised to rational powers, I suggest a separate issue.

[neduard]

Thanks @ericbalawejder and @petertseng ! I've created PR #1914 just for the negative integer tests.