Learning SOLID With PHP

Whats is this project?

This is a very simple project created during a course at Alura Platform to study SOLID principles with PHP. The objective is to refactor an existing project using these principles.

What are SOLID principles?

SOLID is a mnemonic acronym for five design principles intended to make object-oriented designs more understandable, flexible, and maintainable. They are:

1. Single Responsibility Principle
2. Open / Closed Principle
3. Liskov Substitution Principle
4. Interface Segregation Principle
5. Dependency Inversion Principle

1. Single Responsibility Principle

Every class/method SHOULD have only one reason to change.

2. Open / Closed Principle

Software entities (classes, modules, functions, etc.) SHOULD be open for extension, but closed for modification.

3. Liskov Segregation Principle

Subclasses should be substitutable for their base classes. Child classes must never violate the type definitions of the parent class.

4. Dependency Inversion Principle

High-level modules should not depend on low-level modules; both should depend on abstractions.

5. Interface Segregation Principle

Clients should not be forced to depend upon interfaces that they do not use.

Project initialization

This project requires Composer to install its dependencies. If you don't have it installed, go to Composer for more information.

After installing Composer, you can use the command to install dependencies:

composer install

Getting a report on relation between instability x abstraction

Pdepend

Pdepend is a package used to generate reports on dependencies in PHP.

Installation

If you already have used the command composer install to this project, you can skip this step.

To install pdepend

composer require "pdepend/pdepend:2.10.3"

List all commands

vendor\bin\pdepend.bat

Generate chart

vendor\bin\pdepend.bat --jdepend-chart=C:\wamp64\www\learning-solid-with-php\grafico2 C:\wamp64\www\learning-solid-with-php\src

Conclusion

The first image was generated in the begging of the project and shows that the project is far from ideal.

The second image shows that the work in progress is coming up with a good result.

And finally, this project reaches a more ideal state when concrete class depends more on abstract classes than the opposite.

Tests

To make tests i used PHPUnit.

Installation

If you already have used the command composer install to this project, you can skip this step.

composer require --dev phpunit/phpunit ^9

Checking version

vendor\bin\phpunit --version

Generating tests

vendor\bin\phpunit

A file report 'testes-executados.txt' will be created with the results of all tests.