public function testRegister()
 {
     $this->assertFalse($this->_sut->has('ABC'));
     $this->_sut->register('ABC', 'some clazz');
     $this->assertTrue($this->_sut->has('ABC'));
     $result = $this->_sut->getDefinition('ABC');
     $this->assertEquals($result->getClass(), 'some clazz');
 }