spreetail-demo

Overview

This .Net solution comprises a demo of a console application fronting a memory backed multi-value dictionary. The solution's primary purpose is to demonstrate coding techniques I use when implementing an application.

Approach

• I'm not treating this as a throw away code application. Even though the sole purpose is to demo a simple application, I'm still implementing it using best practice software design principles.

• Even though the specifications state that the application need only support string keys and values, I designed it with extensibility in mind so that other data types can be employed.

• I kept scalability in mind while designing the various repository methods. Even though this implementation renders a simple console application, I decided to make all operations on the backing in-memory dictionary thread safe.

• Throughout the code base, you will find SOLID principles implemented.

  • Single Responsibility - each project, class/interface, and method are cohesive and focused on a single responsibility.
  • Open Closed - Each project contains classes that are open for extension and closed for modifications. Examples include the Spreetail.Demo.ConsoleCommands.IConsoleCommand interface which allows adding additional commands to extend functionality.
  • Liskov Substitution - the Spreetail.Demo.ConsoleCommands.ConsoleCommand abstract class contains common logic that all commands use and delegates specific implementation to each command subclass through abstract methods.
  • Interface Segregation - each interface is focused on a particular intention and includes a set of cohesive operations
  • Dependency Inversion - all dependencies are represented through interfaces and concreate implementations are injected within the console project at startup. This provides a seam for extending the various components at runtime.

Structure

The solution is structured into 3 projects.

Spreetail.Demo

This is a console project that handles user input. There are 10 commands available for the user to maintain and display the current state of the multi-value dictionary. The console accepts the various user commands and orchestrates the processing with the Spreetail.Demo.Repository assembly.

Spreetail.Demo.Repository

This is a class libarary that provides repository services for the consuming console application. It is a stand alone library meaning it doesn't have any knowledge of the consuming application. It could conceivably be hosted behind a REST service using HTTP requests as commands. Although the specifications call for the multi-value repository to handle only string keys and values, this repository is set up to be extensible and is not tied to any particular data type.

Spreetail.Demo.Test.Unit

This is a test harness utilizing the XUnit testing framework. Since a vast majority of the work is done in the Spreetail.Demo.Repository, I focused code coverage in that project. It employs the FluentAssertions unit testing assertion framework to provide a more readable testing suite.