====================== Notes on Implementation ========================

• Shopping carts could pontentially be constructed via a builder, but requirements did not call for it
• Could store money in terms of cents (integers) to avoid floating point rounding errors
• Domain Objects are fairly empty. They could potentially be squashed into one class, and having tax rate just be an attribute on the class. To me, the separate domain objects felt cleaner, and formed out of natural progression w/ BDD
• Extending Array: ShoppingBasket technically passes the "is-a" test, but depending on consuming code may or may not be appropriate. It gave quick easy access to Array and Enumberable methods.
• The "shared_examples" formed out of refactoring, and did not initially exist. Having fairly empty scenarios hints at the possiblity of consolidation of the model classes.
• The two shared examples could be potentially combined, if one was ok with including the TAXRATE constant, creating a tax_rate method, has_tax_rate class method, etc
• The math helper mixing in doesn't neccisarily have to exist, as I progressed with BDD, it felt cleaner.