PHPUnit mock interface extending Countable

AbstractTest.php

<?php

namespace Ormigo\Tests;

abstract class AbstractTest extends \PHPUnit_Framework_TestCase
{
    /**
     * Apply expectations for a \Countable on a mock object.
     *
     * @see http://php.net/Countable
     *
     * @param object $mock    A mock object to apply expectations to.
     * @param int    $count   The count to return.
     * @param int    $counter The method invocation start counter.
     *                        This parameter should be altered when using additional
     *                        expectations before the actual count.
     *
     * @return int            The next method invocation counter to add further expectations.
     */
    public function expectCountable($mock, $count, $counter = 0)
    {
        $mock
            ->expects($this->at($counter))
            ->method('count')
            ->will($this->returnValue($count))
        ;

        return ++$counter;
    }
}

ExampleTest.php

<?php

// The usage is fairly simple.
$vouchers = $this->getVoucherCollectionMock();
$this->expectCountable($vouchers, 0);

// see https://gist.github.com/2852498#file_example_test.php for explanations on the $counter parameter.

it would be great if you explain it into a blog post

Yeah, I'm writing on it for both expectations. Should be up by tomorrow evening.