ObjectComparator does not check for Object Hash but internally knows that objects are different.

ObjectTest.php

<?php
/**
 * @author Domenico Lupinetti ostico@gmail.com
 * Date: 11/04/16
 * Time: 19.52
 * 
 * The try block is executed but the comparison are made on Exporter::toArray() 
 * and if the object has no properties $expected and $actual are equals but refers to two different instances
 * ( tried with PDO as example )
 *
 * @see https://github.com/sebastianbergmann/comparator/blob/master/src/ObjectComparator.php#L74
 * @see https://github.com/sebastianbergmann/exporter/blob/master/src/Exporter.php#L152
 *
 */
class ObjectTest extends PHPUnit_Framework_TestCase
{
    public function testObjectEquality(){

        $x = new PDO(
            "mysql:host=mysql;dbname=mydb;charset=UTF8",
            'user',
            'user1',
            array(
                    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION // Raise exceptions on errors
        ) );

        $y = new PDO(
            "mysql:host=mysql;dbname=mydb;charset=UTF8",
            'user',
            'user1',
            array(
                    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION // Raise exceptions on errors
        ) );

        echo("\n");
        var_dump( spl_object_hash( $x ) );
        var_dump( spl_object_hash( $y ) );

        //this is expected to fail
        $this->assertEquals( $x, $y ); // <--- PASS but is WRONG
        
        //this is expected to fail
        $this->assertTrue( $x === $y ); // <--- NOT PASS ( RIGHT )

    }
}