--TEST--
Test Collection::copyOf();
--FILE--
<?php
$array = ['a' => 2, 3 => 'd', 'e' => 'f'];
$collection = Collection::init($array);
$collection1 = $collection->copyOf(2);
$collection2 = $collection->copyOf();
if ($collection1->toArray() != array_slice($array, 0, 2, true) || $collection2->toArray() != $array)
    echo 'Collection::copyOf() failed.', PHP_EOL;
?>
--EXPECT--