itemAt() public method

This overrides the parent implementation by converting the key to lower case first if CaseSensitive is false.
public itemAt ( $key ) : mixed
return mixed the element at the offset, null if no element is found at the offset
 public function testAdd()
 {
     $collection = new TAttributeCollection();
     $collection->add('Property', 'value');
     self::assertEquals('value', $collection->itemAt('Property'));
 }