Order Processing Backend Kata

This Kata is adapted from the More Business Rules Kata from http://codekata.com/.

For this Kata, you will create a REST API using Node.js and Express.js for a business that processes orders and payments over the web. The business produces products A, B, C, D, and E. Assume that the business starts with a stock of 100 units of each product.

Once an order is placed, the business will have to wait for the payment to arrive. Once the payment has arrived, the business will ship the goods if they are in stock, otherwise, they will wait until the goods are in stock before shipping.

If the order was a credit-card order, the business would not have to wait for the payment to arrive and would instead ship the goods as soon as they are in stock.

The customer is able to cancel the order at any time unless the order has already been shipped.

You are provided with the storage-utility, product-utility, and order-utility modules for storing and handling product and order information.

The mock-response module can, but does not have to, be used in writing tests.

Setup

• Download and run the Node.js Installer
• Install Git and follow the Setup Guide
• Create a new branch from main on this repository and name it in the format "Firstname-Lastname"
• Clone your branch of this repository to your device (tutorial)
• Open the terminal in the root directory of this Kata
• Run the command, npm install

Requirements

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Each order should have:

• A unique ID (assigned by the server)
• A customer name
• The date it was placed
• The product that was ordered
• The quantity of the product ordered
• The payment method (either Physical or Credit)
• Its current status (assigned AwaitingPayment, AwaitingStock, or Shipped by the server)

Create tests using Jest as needed. The testing file for "program.ts" would be named "program.spec.ts"

Endpoints

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The API should handle the following order operations:

Endpoint	Method	Description
/orders	GET	Get a list of all orders. This should handle filtering using query parameters.
/orders	POST	Place a new order.
/orders/:orderId	GET	Get an order of a specific ID.
/orders/:orderId	DELETE	Attempt to cancel an order (The order can only be canceled if it hasn't been shipped)
/orders/:orderId/pay	PUT	Notify the system that the payment for an order with a specific ID has arrived.

The API should handle the following stock operations:

Endpoint	Method	Description
/stock/:product	GET	Get the current stock of a product.
/stock/:product	PUT	Update the stock of a product.