• Kotlin
• Jetpack
• XML Layouts
• Ktor
• Picasso
• Hilt
• JUnit4
• Mockk

This project is based on concepts of Clean Architecture, and the layers were divided as below:

The most INNER part of the circle, it contains Entities, Use cases, Services Interfaces and Repositories Interfaces.

• Entity: A data class that represents a Business Model and all its attributes Ex: (A Group, User or Message)
• Use Case: Defines the application behavior; It is responsible for executing every application rule and return data, throw errors, all the application logic resides in use cases; A use case have an Input and/or Output data class.
  1. Use Case Interface: Protocol mainly used for Mocking Test behavior.
  2. Use Case Implementation: Implementation itself of all the logic.
• Services protocols: Protocols that defines the behavior of an API service.
• Repository protocols: Protocols that defines the behavior of a Database repository.

Contains Services and Repository implementations.

• Services Implementations: Services Implementations implements Services Protocols from Domain Layer, in here that you will implement your HTTP, WebSocket code, etc ...
• Repository Implementations: Repository Implementations implements Repository Protocols from Domain Layer; In here that you will implement your Room, SharedPreferences, FileManager code, etc...

🔃 DataSource Layer depends on Domain Layer.

Contains UI of every screen, View, Controllers, ViewModels.
Every screen is structured in MVVM (model, view, and view model).

• ViewModels: A class that is responsible for call actions that can be made on a screen and holds the view state and receive data from UseCases to format it to present in the View.
• Model: A data class that represents all possible states that a screen can have Ex: (List, Errors, Loading Status)
• View: A Fragment view itself, that observe a ViewModel state and calls ViewModel actions.

🔃 Presentation Layer depends on Domain.

Contains SETUP of the entire app, Injections, Application, Core Activity.

All classes of all layers are testable,

• Domain layer has Use Cases unit tests that validate its behaviour.
• Data source layer has Services and Repositories tests that validate mapping, data error, service specific errors, unexpected results...
• Presentation layer has View Models tests that validates entry data, formatting data, actions calls...

In this assignment the features were driven by tests. (TDD)
With this discipline we can prevent unexpected behaviours and develop faster with shorter cycles.

I started the development testing and trying to predict the possible errors and behaviours, but I didn't have time to finish all the tests. You can see the TODOs in the code and the notes in the README.md file. I had started this assignment on the FetchImageLinks, so in there you can see the tests that I had done. Also in the DataSource layer BreedsHttpService you can see the tests that I had done.

My main focus in this assignment was to show my knowledge in the architecture and the tests, so I didn't have time to finish the UI and the tests. It lacks a lot of improvements in the UI, but I think that the architecture and the tests are the most important things in this assignment.

Thank you for reviewing my code, I hope that you like it. 😄