lemattma / taxes_test

Tax calculator receives an input list of product with their prices and categories and outputs the receipt with taxes included.

Tax Calculator

Tax calculator receives an input list of product with their prices and categories and outputs the receipt with taxes included.

Environment

• OSx 10.9.5
• rvm 1.25.33
• ruby-2.0.0-p353

Instalation

# after cloning it
$ bundle install

Usage

$ ruby taxes.rb < INPUT1
$ ruby taxes.rb < INPUT2
$ ruby taxes.rb < INPUT3

Testing

# for running the specs
$ rspec
# or, with guard
$ guard

Description

The application reads lines of comma separated data. Each line contains the following:

Quantity, Name, Price, Categories
1, Book 1, 10, imported|book

Categories are pipe separated and optional you can use any combination of the following: book, food, medical, imported. If no category is specified, a default general good category will be assigned.

Taxes rules

All products, except food, book, medical, will have an 10% tax. On top of this, any imported product will have an additional %5 tax.

Round method

The rounding rules for sales tax are that for a tax rate of n%, a shelf price of p contains (np/100 rounded up to the nearest 0.05) amount of sales tax.

Input example

Quantity, Product, Price, Categories
1, imported bottle of perfume, 27.99, imported
1, bottle of perfume, 18.99
1, packet of headache pills, 9.75, medical
1, box of imported chocolates, 11.25, imported|food

Output example

1, imported bottle of perfume, 32.19
1, bottle of perfume, 20.89
1, packet of headache pills, 9.75
1, box of imported chocolates, 11.85

Sales Taxes: 6.70
Total: 74.68

Design

The taxes.rb file receives the input and create a new instace of App. The invokes the method App#process, passing the input as a parameter and printing the returned string.

The App#process method will create an instance of Cart and will add the products from the input. After this it creates a Tax Class instance (this might differ depending on each country laws), in our case is simply Tax and passes it as a parameter to the Cart#apply_taxes method.

The Cart#apply_taxes method will go through each cart item and will calculate the tax for each product with the method Tax#calculate_tax.

Any Tax Class should implement the method #calculate_tax(product)

TODO

• Optional first line in the input; It's kind of useless for now.
• If 2 products have the same name and price, it should update the existing one in the cart, not adding a new one