1.8. Singleton

To have only one instance of this object in the application that willhandle all calls.

• DB Connector
• Logger (may also be a Multiton if there are many log files forseveral purposes)
• Lock file for the application (there is only one in the filesystem…)

You can also find this code on GitHub

Tests/SingletonTest.php

 
namespace DesignPatterns\Creational\Singleton\Tests;
 
use DesignPatterns\Creational\Singleton\Singleton;
use PHPUnit\Framework\TestCase;
 
class SingletonTest extends TestCase
{
    {
        $firstCall = Singleton::getInstance();
        $secondCall = Singleton::getInstance();
 
        $this->assertInstanceOf(Singleton::class, $firstCall);
        $this->assertSame($firstCall, $secondCall);
    }
}