valid() публичный Метод

Checks if current position is valid
public valid ( ) : boolean
Результат boolean
 /**
  * @test
  */
 public function it_iterator_in_correct_order()
 {
     $a1 = [1, 2, 3];
     $a2 = [4, 7, 10];
     $a3 = [5, 6, 8, 9];
     $it1 = new ArrayIterator($a1);
     $it2 = new ArrayIterator($a2);
     $it3 = new ArrayIterator($a3);
     $compositeIterator = new CompositeIterator([$it1, $it2, $it3], function ($v1, $v2) {
         if (null === $v1) {
             return true;
         }
         return $v1 > $v2;
     });
     $result = [];
     while ($compositeIterator->valid()) {
         $result[] = $compositeIterator->current();
         $compositeIterator->next();
     }
     $compositeIterator->key();
     $compositeIterator->rewind();
     while ($compositeIterator->valid()) {
         $result[] = $compositeIterator->current();
         $compositeIterator->next();
     }
     $this->assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], $result);
 }