public function testExtract()
 {
     $transform = function ($value) {
         return $value . ' extracted';
     };
     $this->type->expects($this->atLeastOnce())->method('extract')->will($this->returnCallback($transform));
     $tab = range(1, 10);
     $expected = array_map($transform, $tab);
     $this->assertEquals($expected, $this->object->extract($tab));
     $value = new \ArrayIterator($tab);
     $this->assertEquals($expected, $this->object->extract($value));
 }