/**
  * @dataProvider provideCases
  */
 function testCases(array $insert, callable $map, array $expect)
 {
     $iterator = new ArrayIterator($insert);
     $mapped = $iterator->map($map);
     $this->assertCount(count($expect), $mapped);
     $this->assertEquals($expect, $mapped->toArray());
 }
 function testMap()
 {
     $iterator = new ArrayIterator([0]);
     $this->assertInstanceOf('Collections\\MappingIterator', $iterator->map(function () {
     }));
 }