We need more thorough test coverage

[Kai-Striega]

Our tests for many of the functions are very sparse, this should be updated to include more tests for each of the functions in numpy-financial. In particular, I think we need more thorough testing of edge cases.

The test can be modified by editing test_financial.py.

[Kai-Striega]

@jdilanzo I think you might be interested in this

[jlopezpena]

Financial math functions are very amenable to property based testing, which excels at finding edge cases. Would it be acceptable to add a dev/test dependency on hypothesis? If so, I can give a hand at designing sampling strategies and property based tests.

[Kai-Striega]

Hypothesis looks like a great addition. I'm happy to add it as a dev dependency. I don't have much experience with hypothesis, although I've been meaning to try it out for a while. So I might need a wile to get up to speed

[Kai-Striega]

@kalicialopez You might be interested in this :)

[Kai-Striega]

I've been thinking about this some more and, at a minimum, I'd like to confirm each function:

• Supports decimal.Decimal type
• Supports broadcasting behaviour

I'm also amicable to using hypothesis as suggested earlier