Supermarket Checkout System

This project implements a flexible supermarket checkout system that applies various pricing rules. It includes a service layer for processing checkout operations and unit tests to ensure correctness.

Products in the Database

Currently, we have only three products in the database:

Product Code	Name	Price
FR1	Fruit Tea	£3.11
SR1	Strawberries	£5.00
CF1	Coffee	£11.23

Features

• Buy One Get One Free: Applies to specific products. (Currently configured for product code 'FR1' as you will see in the config below)
• Bulk Discount: Applies discounts when a minimum quantity of a product is purchased. (Currently configured for product code 'SR1'- when you buy 3 you get one free- as you will see in the config below)
• Flexible Pricing Rules: Configurable via a PHP configuration file.

Installation

1. Clone the repository:

   cd supermarket-checkout

2. Install dependencies:

   composer install

3. Setup environment:

   Copy the example environment file adjust the configuration as needed ie setup the db creds:

   cp .env.example .env

4. Run database migrations and seeders:

   php artisan migrate --seed

Configuration

The pricing rules are configured in config/pricing_rules.php:

return [
    'rules' => [
        [
            'class' => \App\Services\PricingRules\BuyOneGetOneFreeRule::class,
            'params' => [
                ['FR1'] // array of product_codes on which discount is to be applied on
            ],
        ],
        [
            'class' => \App\Services\PricingRules\BulkDiscountRule::class,
            'params' => [
                ['SR1'], // array of product_codes on which discount is to be applied on
                3, // units
                4.50], //discount
        ],
    ],
];

Usage using cURL

curl -X POST http://yourdomain.com/api/checkout \
     -H "Content-Type: application/json" \
     -d '{"products":[{"code":"FR1"},{"code":"SR1"}]}'

Success Response

{
    "total": 10.50
}

Error Response:

{
    "error": "Failed to process product: FR1"
}

Testing

After setting up the PHPUnit.xml file run the following command

php artisan test --filter Feature or --filter Unit

Currently, the coverage is 100%!

License

This project is open-sourced software licensed under the MIT license.

Author

Osmar Rodrigues (https://github.com/Reaper1994)