Smart Home Refactoring C++ Kata

Overview

This kata complements Clean Code: SOLID, Ep. 13 - Dependency Inversion Principle.

In this exercise, you'll practice refactoring code to adhere to the Dependency Inversion Principle (DIP). You'll be working with a smart home system that controls different types of lights and an air conditioner.

Instructions

Exercise 1

The initial code consists of several device classes and the SmartHomeController class, which is responsible for controlling all the devices (lights and air conditioner).

However, the initial code violates the Dependency Inversion Principle, as the SmartHomeController class directly depends on concrete classes. In the tests, we also directly manipulate the dimmable_light and networkable_light instances to check their unique behaviors.

Your goal is to refactor the code to adhere to the Dependency Inversion Principle and make it easier to implement new devices.

Here are some guidelines to follow:

1. Introduce an interface or several interfaces (or abstract base classes) for the devices that the SmartHomeController interacts with.

2. Update the SmartHomeController class to depend on this interface, instead of the concrete device classes.

3. Update the devices to implement these interfaces.

4. Modify any constructors or method calls as necessary to accommodate the refactoring.

Note

Remember that in this exercise, we assume all devices are in an ideal state and don't account for error cases such as a network connection failure or an attempt to dim a light below 0% or above 100% brightness.

Make sure the program still behaves the same way after your refactoring. There's a unit test in place that checks that on a very rudimentary level by just looking at the output of the program.

Exercise 2

When you're done with refactoring, test the quality of your refactoring by implementing two additional scenarios (methods) in SmartHomeController:

1. Add the make_quick_breakfast scenario to open the blinds and make a predefined coffee type.

   1. Add Blinds device class with open and close methods (blinds are always powered and does not have on/off function).
   2. Add make_quick_breakfast method to SmartHomeController.

2. Add automatic vacuum cleaner and the schedule_night_cleaning scenario, which should start the cleaning once everything else is turned off.

   1. Add VacuumCleaner device class with start_cleaning and stop_cleaning methods.
   2. Add schedule_night_cleaning method to SmartHomeController. After calling this method, the vacuum cleaner should start cleaning once all other devices are turned off.

Evaluate whether or not your refactoring made life easier for you, or not.

Usage

You can import this project into Replit, and it will handle all dependencies automatically.

Prerequisites

• CMake 3.19+
• Ninja
• GTest

Build

make

Run main

make run

Run tests

make test