public function testSort()
{
$array = [1, 2, 3, 4, 5];
$seq = new Sequence($array);
$this->assertEquals([1, 2, 3, 4, 5], $seq->sort()->toArray());
$this->assertEquals($array, $seq->toArray());
//check that original colection is unaltered
$this->assertEquals([5, 4, 3, 2, 1], $seq->sort(function ($a, $b) {
return $a === $b ? 0 : $a > $b ? -1 : 1;
})->toArray());
}
