private function initializeBook($fixtureClass)
 {
     $container = new Container('php://memory', 'php://memory', 'Bookdown\\Bookdown\\FakeFsio');
     $this->fsio = $container->getFsio();
     $this->fsio->setFiles(array('/path/to/chapter/img/test4.jpg' => '', '/path/to/chapter/../img/test5.jpg' => ''));
     $this->fixture = new $fixtureClass($this->fsio);
     $builder = $container->newProcessorBuilder();
     $conversion = $builder->newProcess($this->fixture->rootConfig, 'Conversion');
     $conversion->__invoke($this->fixture->rootPage);
     $conversion->__invoke($this->fixture->indexPage);
     $conversion->__invoke($this->fixture->page);
     $this->process = $builder->newProcess($this->fixture->rootConfig, 'CopyImage');
 }