Question

How do I make my stub act like an ArrayIterator, for example? I mean, I want to iterate over this stub. It’s an exercise from Practical PHP Testing.

7.2
Write a EvenIterator which takes a FibonacciIterator an iterates only
on the even-indexed values (returning 0, 1, 3, 8, 21...).
7.3
Write tests for the EvenIterator class, stubbing out the
FibonacciIterator using an ArrayIterator in substitution, which is provided
by the Spl (otherwise it will never terminate!)

Thanks.

Answer 1

If I understand correctly the task here is to test EvenIterator by using ArrayIterator as a stub for FibonacciIterator.
So for example load ArrayIterator with array of even values, pass it to EvenIterator and you should get same values. Then do the same with array of odd values, and you should get empty resultset.

---

class EvenIteratorTest extends \PHPUnit_Framework_TestCase {

  public function testDoesNotRemoveEvens() {

    $data = array(2,4,6,8);
    $arrayIterator = new \ArrayIterator($data);
    $object = new EvenIterator($arrayIterator);

    $expected = $data;
    $actual = array();
    foreach($object as $v) {
      $actual[] = $v;
    }
    $this->assertEquals($expected,$actual);
  }

  public function testFiltersOutOdds() {

    $data = array(1,3,5,7);
    $arrayIterator = new \ArrayIterator($data);
    $object = new EvenIterator($arrayIterator);

    $actual = array();
    foreach($object as $v) {
      $actual[] = $v;
    }
    $this->assertEmpty($actual);
  }

}

As you can see, there’s a lot of duplicated code, so some refactoring would be in place.