Develop a solution that simulate the delivery of notes when a client does a withdraw in a cash machine.
The basic requirements are the follow:
Always deliver the lowest number of possible notes;
It’s possible to get the amount requested with available notes;
The client balance is infinite;
Amount of notes is infinite;
Available notes $ 100,00; $ 50,00; $ 20,00 e $ 10,00
Example:
Entry: 30.00
Result: [20.00, 10.00]
Entry: 80.00
Result: [50.00, 20.00, 10.00]
Entry: 125.00
Result: throw NoteUnavailableException
Entry: -130.00
Result: throw InvalidArgumentException
Entry: NULL
Result: [Empty Set]
We just have one endpoints to receive the value.
GET /{value}?
The {value} not required
./vendor/bin/simple-phpunit
There a unit and integration tests.
The project is very simple, not required webservice e.g nginx
Just run the command bellow
./bin/console server:start
The problem is very simple and definitely not need the framework to solve it.
But to show more skills I decided to use a framework, and the choice for Symfony was very easy for me for reasons below:
- very extensible;
- huge community;
- robust
- fast when you use the proper settings for cache
- dependency injector/ service container more easy to use, define service in files (yml, xml, php)
The decision for version 3.4 was because is LTS.
Regarding the CashMachine I split for 3 services to respect the SOLID:
- ValidatorService
- BankNotes
- CashMachine
The responsible to validate input and if the value is able to business logic
BankNotes to provide the notes and the logic for server notes,
The CashMachineService not need have knowledge of provider, just only trusty in their Interface.
CashMachineService is responsible to call notes from BankNoteService and delivery notes.
For the controller I use the ParamConverter for get the value and validate it on layer of controller,
but totally decouple of controller.
- Use DTO to response,
- Provider the Listener to catch the DTO and transform to json (avoid to use JMS) maybe the JsonSerializable
- Provide the possible errors code with a good description
- Use the HATEOAS (Hypermedia As The Engine Of Application State)
- Docker