[PHP] A Primer On Reflection in PHP (And How It Plays Into Unit Testing)

00-apiClient.php

<?php

namespace Acme\Plugin;

class APIClient
{
  private $username;

  // Other functions for class implementation...
}

01-APIClientTest.php

<?php

namespace Acme\Plugin\Tests;

use Acme\Plugin\API\APIClient;

class APIClientTest
{
  public function setUsername()
  {
   
    // Instantiate the class.
    $client = new APIClient();
    $username = 'tommcfarlin';
    $client->setUsername($username);


    // Now get a reflected instance of the class.
    $reflectedClient = new ReflectionClass('Acme\Plugin\API\APIClient');
    
    // More to come...
  }
}
  

01-setUsername.php

<?php

namespace Acme\Plugin;

class APIClient
{
  private $username;

  public function setUsername($username)
  {
    $this->username = $username;
  }
  
  // Other functions for class implementation...
}
  

02-setAccessibleProperty.php

<?php

namespace Acme\Plugin\Tests;

use Acme\Plugin\API\APIClient;

class APIClientTest
{
  public function setUsername()
  {
   
    // Instantiate the class.
    $client = new APIClient();
    $username = 'tommcfarlin';
    $client->setUsername($username);


    // Now get a reflected instance of the class.
    $reflectedClient = new ReflectionClass('Acme\Plugin\API\APIClient');
    $usernameProperty = new ReflectionObject($client);
    $usernameProperty->setAccessible(true);
    
    // More to come...
  }
}
  

03-readPropertyValue.php

<?php

namespace Acme\Plugin\Tests;

use Acme\Plugin\API\APIClient;

class APIClientTest
{
  public function setUsername()
  {
   
    // Instantiate the class.
    $client = new APIClient();
    $username = 'tommcfarlin';
    $client->setUsername($username);


    // Now get a reflected instance of the class.
    $reflectedClient = new ReflectionClass('Acme\Plugin\API\APIClient');
    
    // Grab a reference to the private property by making it accessible.
    $usernameProperty = new ReflectionObject($client);
    $usernameProperty->setAccessible(true);
    
    // And finally, read it's value.
    $usernameValue = $usernameProperty->getValue($client);
  }
}