Testing Closures

closure-test.php

<?php

interface Item
{
    public function runAction();
}

interface SomeCollection
{
    public function foreachItem(callable $fn);
}

class CollectionUseSpec extends ObjectBehavior
{
    function it_iterates_collection(SomeCollection $collection, Item $item)
    {
        $collection->foreachItem(Argument::that(
            function ($fn) use ($item) {
                $fn($item);
                
                return true;
            }
        ))->willReturn();
        
        $this->run($collection);
        
        $item->runAction()->shouldHaveBeenCalled();
    }
}

class CollectionUse
{
    public function run(SomeCollection $collection)
    {
        $collection->foreachItem(function (Item $item) {
            $item->runAction();
        })
    }
}