Mocking Iterator using PHPUnit via a helper method

<?php

include_once dirname(__FILE__) . '/../lib/exampleList.php';

/**
 * Tests for _mock_ Iterator
 *
 * Here we have added a helper method (which you could add to your own abstract
 * base test class) that will help us mock iterators quickly and easily.
 *
 * @author Dave Gardner <dave@davegardner.me.uk>
 */
class mockedIteratorTest extends PHPUnit_Framework_TestCase
{
    private function buildSystemUnderTest()
    {
        return $this->getMock('exampleList');
    }

    /**
     * Mock iterator
     *
     * This attaches all the required expectations in the right order so that
     * our iterator will act like an iterator!
     *
     * @param Iterator $iterator The iterator object; this is what we attach
     *      all the expectations to
     * @param array An array of items that we will mock up, we will use the
     *      keys (if needed) and values of this array to return
     * @param boolean $includeCallsToKey Whether we want to mock up the calls
     *      to "key"; only needed if you are doing foreach ($foo as $k => $v)
     *      as opposed to foreach ($foo as $v)
     */
    private function mockIterator(
            Iterator $iterator,
            array $items,
            $includeCallsToKey = FALSE
            )
    {
        $iterator->expects($this->at(0))
                 ->method('rewind');
        $counter = 1;
        foreach ($items as $k => $v)
        {
            $iterator->expects($this->at($counter++))
                     ->method('valid')
                     ->will($this->returnValue(TRUE));
            $iterator->expects($this->at($counter++))
                     ->method('current')
                     ->will($this->returnValue($v));
            if ($includeCallsToKey)
            {
                $iterator->expects($this->at($counter++))
                         ->method('key')
                         ->will($this->returnValue($k));
            }
            $iterator->expects($this->at($counter++))
                     ->method('next');
        }
        $iterator->expects($this->at($counter))
                 ->method('valid')
                 ->will($this->returnValue(FALSE));
    }

    public function testConstructs()
    {
        $list = $this->buildSystemUnderTest();
        $this->assertInstanceOf('exampleList', $list);
        $this->assertInstanceOf('Iterator', $list);
    }

    public function testHasZeroItemsWhenWeHaventMockedMethods()
    {
        $list = $this->buildSystemUnderTest();
        $counter = 0;
        foreach ($list as $item)
        {
            $counter++;
        }
        $this->assertEquals(0, $counter);
    }

    public function testWhenMockOneIterationWithNoKey()
    {
        $list = $this->buildSystemUnderTest();

        $this->mockIterator($list, array('This is the first item'));

        $counter = 0;
        foreach ($list as $value)
        {
            $counter++;
        }
        $this->assertEquals(1, $counter);
        $this->assertEquals('This is the first item', $value);
    }

    public function testWhenMockOneIterationWithKey()
    {
        $list = $this->buildSystemUnderTest();

        $this->mockIterator($list, array('key1' => 'This is the first item'), TRUE);

        $counter = 0;
        foreach ($list as $key => $value)
        {
            $counter++;
        }
        $this->assertEquals(1, $counter);
        $this->assertEquals('key1', $key);
        $this->assertEquals('This is the first item', $value);
    }

    public function testWhenMockThreeIterationWithNoKey()
    {
        $list = $this->buildSystemUnderTest();

        $expectedValues = array(
            'This is the first item',
            'This is the second item',
            'And the final item'
        );
        $this->mockIterator($list, $expectedValues);

        $counter = 0;
        $values = array();
        foreach ($list as $value)
        {
            $values[] = $value;
            $counter++;
        }
        $this->assertEquals(3, $counter);

        $this->assertEquals($expectedValues, $values);
    }

    public function testWhenMockThreeIterationWithKey()
    {
        $list = $this->buildSystemUnderTest();

        $expectedValues = array(
            'item1' => 'This is the first item',
            'foo'   => 'This is the second item!!',
            'bar'   => 'And the final item'
        );
        $this->mockIterator($list, $expectedValues, TRUE);

        $counter = 0;
        $values = array();
        foreach ($list as $key => $value)
        {
            $values[$key] = $value;
            $counter++;
        }
        $this->assertEquals(3, $counter);

        $this->assertEquals($expectedValues, $values);
    }
}