SaasTeamBackendTest

SAAS Team takehome backend test

Required software

Install the following dependencies:

Docker and Docker Compose
Make or equivalent make processor

System Setup

Run make build before you begin, to build the docker images.

Run make dev to stand up the service.

If it is working, running

curl 'http://0.0.0.0:8000/health'

should return OK and running

curl 'http://0.0.0.0:8000/products'

should return a JSON object containing the 4 products in the system.

Run make test_before and all tests should pass.

Tasks

1) Tests

Fix any bugs that prevent make test_after from passing successfully. Note this will cause make test_before to fail, this is expected.
Note that in order to do all of this, the following tasks will need to be completed.

2) ProductType

Implement a new field on products in the system called ProductType.
Product 1 and 2 are a "food", Product 3 and 4 are "sporting_good".

3) Hidden Fields

The Product model contains hidden fields that we don't want to expose through the GET endpoints, but want to keep internally.
Both product_discount_price and coupon_code should be hidden fields and should not be exposed through the GET /products or GET /products/{product_id} endpoint.
Fix the system such that product_discount_price and coupon_code are still fields that can be set with POST /products, but are not returned to the user through the GET endpoints.

4) Calculate Price

Implement the /calculate-price API endpoint.
This API should take a JSON payload containing an array (cart) of objects containing a product_id, quantity, and an optional field coupon_code. Eg:

{
  "cart": [
    {
      "product_id": 1,
      "quantity": 2,
      "coupon_code": "food50"
    },
    {
      "product_id": 2,
      "quantity": 4      
    },
  ]
}

/calculate-price should return a JSON consisting of the total_objects and total_cost for the entire cart. The response should be in the form:

{
	total_objects: int,
	total_cost: int
}

It is up to you to define the request payload and implement it. Add any code at any level to return the correct responses.
If the cart consists of some valid items and some invalid items (product_id does not exist), only tally the valid items.
If a product in the cart has a valid coupon code, the new price of the product should be the product discount price.
If the cart is empty or consists of only invalid items, return an HTTP 200 OK with the following body:

{
	total_objects: 0,
	total_cost: 0
}

5) Error Handling

Currently any and all errors in the system will throw a HTTP 500 Internal Server Error, we don't want this. Fix the handler responses with the following rules:
- 400 Bad Request
  - If the request payload is malformed.
  - This applies to the POST /products and POST /calculate-price endpoints.
- 404 Not Found
  - If the request's ID is not found.
  - This applies to the GET /products/{product_id} endpoint.

6) Add a store

Right now the GET products endpoint returns an hardcoded list of products and the POST to create a new product only returns a payload, but no new product is actually created. Define an interface to store and retrieve products from storage and add at least one implementation backed by any storage method you prefer (database, JSON file, in-memory data structure). It doesn't matter if the stored data won't survive a reboot of the Docker container, as long as products can be added and fetched while the process lives. The tests should be fixed accordingly to take into account the new changes. Everything needs to keep working out of the box with make dev, so make sure that new dependencies (if any) are added to the docker-compose file.

omegagussan / go