add observer pattern and related test

Author: basherr

app/Controller/BehavioralController.php

@@ -24,7 +24,11 @@ public function command()
 
   public function iterator()
   {
-    // (new \App\Factory\Behavioral\Iterator\UserRoles\Application)->run();
     (new \App\Factory\Behavioral\Iterator\HotelSuppliers\Application)->run();
   }
+
+  public function observer()
+  {
+    (new \App\Factory\Behavioral\Observer\NewUserSignedup\Application)->run();
+  }
 }

app/Factory/Behavioral/Observer/NewUserSignedup/Application.php

@@ -0,0 +1,20 @@
+<?php namespace App\Factory\Behavioral\Observer\NewUserSignedup;
+
+class Application
+{
+  public function run()
+  {
+    $observer1 = new ConfirmWhatsapp();
+    $observer2 = new SendConfirmationEmail();
+
+    $observable = new NewUserSignedup(new User('[email protected]', '123123123'));
+    $observable->attach($observer1);
+    $observable->attach($observer2);
+    $observable->notify();
+    echo '<pre>Whatsapp observer detached';
+    $observable->detach($observer1);
+
+    $observable->setUser(new User('[email protected]', '123123123'));
+    $observable->notify();
+  }
+}

app/Factory/Behavioral/Observer/NewUserSignedup/ConfirmWhatsapp.php

@@ -0,0 +1,9 @@
+<?php namespace App\Factory\Behavioral\Observer\NewUserSignedup;
+
+class ConfirmWhatsapp implements \SplObserver
+{
+  public function update(\SplSubject $subject)
+  {
+    echo '<pre>Sending text to: ' . $subject->getUser()->getPhoneNo();
+  }
+}

app/Factory/Behavioral/Observer/NewUserSignedup/NewUserSignedup.php

@@ -0,0 +1,44 @@
+<?php namespace App\Factory\Behavioral\Observer\NewUserSignedup;
+
+class NewUserSignedup implements \SplSubject
+{
+  private $observers = [];
+  private $_user;
+
+  public function __construct(User $user)
+  {
+    $this->_user = $user;
+  }
+
+  public function attach(\SplObserver $observer)
+  {
+    $this->observers[] = $observer;
+  }
+
+  public function detach(\SplObserver $observer)
+  {
+    foreach($this->observers as $k => $obs) {
+      if($observer === $obs) {
+        unset($this->observers[$k]);
+        break;
+      }
+    }
+  }
+
+  public function notify(): void
+  {
+    foreach($this->observers as $observer) {
+      $observer->update($this);
+    }
+  }
+
+  public function setUser(User $user)
+  {
+    $this->_user = $user;
+  }
+
+  public function getUser()
+  {
+    return $this->_user;
+  }
+}

app/Factory/Behavioral/Observer/NewUserSignedup/SendConfirmationEmail.php

@@ -0,0 +1,9 @@
+<?php namespace App\Factory\Behavioral\Observer\NewUserSignedup;
+
+class SendConfirmationEmail implements \SplObserver
+{
+  public function update(\SplSubject $subject)
+  {
+    echo '<pre>Sending email to: ' . $subject->getUser()->getEmail();
+  }
+}

app/Factory/Behavioral/Observer/NewUserSignedup/User.php

@@ -0,0 +1,23 @@
+<?php namespace App\Factory\Behavioral\Observer\NewUserSignedup;
+
+class User
+{
+  private $_email;
+  private $_phoneNum;
+
+  public function __construct(string $email, string $phoneNum)
+  {
+    $this->_email = $email;
+    $this->_phoneNum = $phoneNum;
+  }
+
+  public function getPhoneNo()
+  {
+    return $this->_phoneNum;
+  }
+
+  public function getEmail()
+  {
+    return $this->_email;
+  }
+}

bootstraps/routes.php

@@ -21,5 +21,6 @@
     ['GET', '/behavioral', ['App\Controller\BehavioralController', 'chainOfResponsibility']],
     ['GET', '/behavioral/command', ['App\Controller\BehavioralController', 'command']],
     ['GET', '/behavioral/iterator', ['App\Controller\BehavioralController', 'iterator']],
+    ['GET', '/behavioral/observer', ['App\Controller\BehavioralController', 'observer']],
     // ['GET', '/{slug}', ['App\Controller\CreationalController', 'show']],
 ];

tests/ObserverPatternTest.php

@@ -0,0 +1,31 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use App\Factory\Behavioral\Observer\NewUserSignedup\{
+  User,
+  NewUserSignedup,
+  ConfirmWhatsapp,
+  SendConfirmationEmail
+};
+
+class ObserverPatternTest extends TestCase {
+  public function testUserCanNotifyWhatsappObserver()
+  {
+    $user = new User('[email protected]', '123123123');
+    $observable = new NewUserSignedup($user);
+    $observable->attach(new ConfirmWhatsapp);
+
+    $this->expectOutputString('Sending text to: ' . $user->getPhoneNo());
+    $observable->notify();
+  }
+
+  public function testUserCanNotifyEmailObserver()
+  {
+    $user = new User('[email protected]', '123123123');
+    $observable = new NewUserSignedup($user);
+    $observable->attach(new SendConfirmationEmail);
+
+    $this->expectOutputString('Sending email to: ' . $user->getEmail());
+    $observable->notify();
+  }
+}