/**
* @param Enumerator $collection
* @param callable $add This callable will add an item to $collection.
*/
function doMapTests(Enumerator $collection, callable $add)
{
$add(0);
$add(1);
$add(2);
$add(3);
$a = $collection->map(function ($value, $key) {
return [$value * 2, $key];
});
$this->assertCount(4, $a);
$expect = [0, 2, 4, 6];
foreach ($a as $key => $value) {
$this->assertEquals($expect[$key], $value[0]);
}
}
