salvobee/supermarket-checkout

A simple checkout system that calculates total price against a set of rules

Supermarket Checkout

This repository contains code to implement a supermarket style checkout system, where product are "scanned" one by one, and the total is calculated against a set of pricing rules.

The code is inspired by a YouTube video published on Laravel Daily channel.

The video is about a job interview where the candidate was asked to satisfy some basic requirements to apply interactively a set of discount rules while the scanner passes the products. In the requirements there was some examples of carts and expected totals, so it was a perfect task to improve my skills on TDD. For this reason I've decided to write the code by myself and publish it on Github for future reference.

Usage

The code has no "entry points", so to execute it you have just to run the tests.

First of all install dev dependencies after cloning the repository

$ composer install

Then run phpunit tests with the script provided in composer.json

$ composer test

Have fun exploring how the test was passed using the Strategy Pattern, start from tests/Feature/CheckoutTest.php and traverse the source trough the classes and methods used on the test code.

Since this was just a proof-of-concept, I didn't code any database interface object, but I've just used a plain array sto store products and rules in a repository class, where products are mapped to models and rules are considered as a strategy classes to calculate the price against the quantity in the cart.