Have fun and learn!

This is what this repository is all about. After watching this, this, this, this, this and also this I decided to experiment with property based tests and contracts. This repository is all about experimenting with that. In order to do that I am using a simple 2D vector library that I wrote in the past.

To make things even more fun I am going to experiment with several implementations of the 2D vector lib.

How to run

This repository uses pipenv. Just run pipenv install on the root of this repository and everything will be setup. Then pipenv shell and pytest on the src folder. You can also run it the old school style (install the packages globaly).

What I learned

1. Float arithmetic with fixed number of bits is weird.
2. Property based tests finds edge cases that you would (probably) never think of
3. Converting int to float can cause some unexpected errors (i.e. a number that can fit in an int but not a float)
4. Interfacing with objects in C makes it very hard to ensure that arithmetic works as expected. When passing numbers around it is very easy to lose precision when dealing with "big" numbers like 2^31. YMMV depending on archteture I guess. I am pretty much limiting the range of numbers that can be passed to C in order to avoid losing some bits around.
5. Achieving 100% test coverage with property based tests can be pretty brutal. Lots of edge cases to cover, some of which may be out of the intended use cases.