public function test_size()
 {
     $coll = new Collection();
     $coll->addItem('Test Item', 1);
     $actual = $coll->length();
     $expected = 1;
     $this->assertEquals($expected, $actual);
 }
 /**
  * Validate pointer's position (non-PHPdoc)
  * 
  * @see Iterator::valid()
  */
 public function valid()
 {
     return $this->_currIndex < $this->_collection->length();
 }