Cleanup

Test process of selecting product, receiving change, item is now sold out

Create full process test

New coin return test

All tests pass

Return coins test is successful

Refactoring mostly complete. All tests pass except for coin return tests.

Test Coin creation

Begin coin refactor. First successful coin test.

More "Sold Out" tests

Another "Sold Out" test

Additional "Sold Out" test

First "Sold Out" test

Small tweaks

Implemented "Return Coins"