--TEST--
SPL: SplObserver and SplSubject (empty notify)
--FILE--
<?php

class ObserverImpl implements SplObserver
{
    protected $name = '';

    function __construct($name = 'obj')
    {
        $this->name = '$' . $name;
    }

    function update(SplSubject $subject): void
    {
        echo $this->name . '->' . __METHOD__ . '(' . $subject->getName() . ");\n";
    }

    function getName()
    {
        return $this->name;
    }
}

class SubjectImpl implements SplSubject
{
    protected $name = '';
    protected $observers = array();

    function __construct($name = 'sub')
    {
        $this->name = '$' . $name;
    }

    function attach(SplObserver $observer): void
    {
        echo '$sub->' . __METHOD__ . '(' . $observer->getName() . ");\n";
        if (!in_array($observer, $this->observers))
        {
            $this->observers[] = $observer;
        }
    }

    function detach(SplObserver $observer): void
    {
        echo '$sub->' . __METHOD__ . '(' . $observer->getName() . ");\n";
        $idx = array_search($observer, $this->observers);
        if ($idx !== false)
        {
            unset($this->observers[$idx]);
        }
    }

    function notify(): void
    {
        echo '$sub->' . __METHOD__ . "();\n";
        foreach($this->observers as $observer)
        {
            $observer->update($this);
        }
    }

    function getName()
    {
        return $this->name;
    }
}

$sub = new SubjectImpl;

$ob1 = new ObserverImpl("ob1");
$ob2 = new ObserverImpl("ob2");
$ob3 = new ObserverImpl("ob3");

$sub->attach($ob1);
$sub->attach($ob1);
$sub->attach($ob2);
$sub->attach($ob3);

$sub->notify();

$sub->detach($ob3);

$sub->notify();

$sub->detach($ob2);
$sub->detach($ob1);

$sub->notify();

$sub->attach($ob3);

$sub->notify();
?>
--EXPECT--
$sub->SubjectImpl::attach($ob1);
$sub->SubjectImpl::attach($ob1);
$sub->SubjectImpl::attach($ob2);
$sub->SubjectImpl::attach($ob3);
$sub->SubjectImpl::notify();
$ob1->ObserverImpl::update($sub);
$ob2->ObserverImpl::update($sub);
$ob3->ObserverImpl::update($sub);
$sub->SubjectImpl::detach($ob3);
$sub->SubjectImpl::notify();
$ob1->ObserverImpl::update($sub);
$ob2->ObserverImpl::update($sub);
$sub->SubjectImpl::detach($ob2);
$sub->SubjectImpl::detach($ob1);
$sub->SubjectImpl::notify();
$sub->SubjectImpl::attach($ob3);
$sub->SubjectImpl::notify();
$ob3->ObserverImpl::update($sub);