public function testNormalizersClearing()
 {
     $collection = new Collection(['X' => 'a', 'y' => 'b', 'Z' => 'C']);
     $collection->addNormalizer(function (&$value) {
         $value = strtolower($value);
     });
     $this->assertCount(1, $collection->getNormalizers());
     $collection->clearNormalizers();
     $this->assertEmpty($collection->getNormalizers());
 }