TASK: Refactor code

Do not include output logic into services.
Also do not couple comparison with crawling.

Use Symfony Events to connect features.

comparison

@@ -5,9 +5,31 @@ require __DIR__ . '/vendor/autoload.php';
 
 use Codappix\WebsiteComparison\Command\CompareCommand;
 use Codappix\WebsiteComparison\Command\CreateBaseCommand;
+use Facebook\WebDriver\Chrome\ChromeDriver;
+use Facebook\WebDriver\Chrome\ChromeDriverService;
 use Symfony\Component\Console\Application;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+
+$eventDispatcher = new EventDispatcher();
+
+$chromeDriver = (function () {
+    $chromeDriverService = new ChromeDriverService(
+        '/usr/lib/chromium-browser/chromedriver',
+        9515,
+        [
+            '--port=9515',
+            '--headless',
+        ]
+    );
+
+    return ChromeDriver::start(null, $chromeDriverService);
+})();
 
 $application = new Application();
-$application->add(new CreateBaseCommand());
+$application->setDispatcher($eventDispatcher);
-$application->add(new CompareCommand());
+
+// TODO: Use factory for commands, which injects event dispatcher and chrome driver?
+$application->add(new CreateBaseCommand($eventDispatcher, $chromeDriver));
+$application->add(new CompareCommand($eventDispatcher, $chromeDriver));
+
 $application->run();

composer.json

@@ -16,10 +16,11 @@
     },
     "require": {
         "php": "^7.2",
-        "php-imagick": "*",
+        "ext-imagick": "*",
         "facebook/webdriver": "^1.6",
         "symfony/console": "^4.1",
         "symfony/process": "^4.1",
-        "guzzlehttp/psr7": "^1.4"
+        "guzzlehttp/psr7": "^1.4",
+        "symfony/event-dispatcher": "^4.1"
     }
 }

src/Command/CompareCommand.php

@@ -21,23 +21,39 @@ namespace Codappix\WebsiteComparison\Command;
  * 02110-1301, USA.
  */
 
-use Codappix\WebsiteComparison\Service\ScreenshotCrawlerService;
+use Codappix\WebsiteComparison\Service\Screenshot\CompareService;
-use Facebook\WebDriver\Chrome\ChromeDriver;
+use Codappix\WebsiteComparison\Service\Screenshot\CrawlerService;
-use Facebook\WebDriver\Chrome\ChromeDriverService;
+use Codappix\WebsiteComparison\Service\Screenshot\Service;
+use Facebook\WebDriver\Remote\RemoteWebDriver;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
-use Symfony\Component\Process\Exception\ProcessFailedException;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
-use Symfony\Component\Process\Process;
+use Symfony\Component\EventDispatcher\GenericEvent;
 
 class CompareCommand extends Command
 {
     /**
-     * @var Process
+     * @var EventDispatcherInterface
      */
-    protected $chromeProcess;
+    protected $eventDispatcher;
+
+    /**
+     * @var RemoteWebDriver
+     */
+    protected $webDriver;
+
+    public function __construct(
+        EventDispatcherInterface $eventDispatcher,
+        RemoteWebDriver $webDriver
+    ) {
+        parent::__construct(null);
+
+        $this->eventDispatcher = $eventDispatcher;
+        $this->webDriver = $webDriver;
+    }
 
     protected function configure()
     {
@@ -85,35 +101,80 @@ class CompareCommand extends Command
 
     protected function execute(InputInterface $input, OutputInterface $output)
     {
-        $screenshotCrawler = new ScreenshotCrawlerService(
+
-            $output,
+        $screenshotService = new Service(
-            $this->getDriver(),
+            $this->eventDispatcher,
-            $input->getArgument('baseUrl'),
             $input->getOption('compareDir'),
             $input->getOption('screenshotWidth')
         );
-        $hasDifferences = $screenshotCrawler->compare(
+
+        $screenshotCrawler = new CrawlerService(
+            $this->webDriver,
+            $screenshotService,
+            $input->getArgument('baseUrl')
+        );
+
+        $compareService = new CompareService(
+            $this->eventDispatcher,
+            $screenshotService,
             $input->getOption('screenshotDir'),
             $input->getOption('diffResultDir')
         );
+        $this->registerEvents($output, $compareService);
 
-        if ($hasDifferences) {
+        $screenshotCrawler->crawl();
+
+        if ($compareService->hasDifferences()) {
             return 255;
         }
     }
 
-    protected function getDriver(): ChromeDriver
+    protected function registerEvents(OutputInterface $output, CompareService $compareService)
     {
-        $chromeDriverService = new ChromeDriverService(
+        $this->eventDispatcher->addListener(
-            '/usr/lib/chromium-browser/chromedriver',
+            'service.screenshot.created',
-            9515,
+            function (GenericEvent $event) use ($output, $compareService) {
-            [
+                $output->writeln(sprintf(
-                '--port=9515',
+                    '<info>Comparing Screenshot for url "%s".</info>',
-                '--headless',
+                    $event->getArgument('url')
-            ]
+                ));
+                $compareService->compareScreenshot(
+                    $event->getArgument('screenshot')
+                );
+            }
         );
-        $driver = ChromeDriver::start(null, $chromeDriverService);
 
-        return $driver;
+        if ($output->isVerbose()) {
+            $this->eventDispatcher->addListener(
+                'service.screenshot.isSame',
+                function (GenericEvent $event) use ($output) {
+                    $output->writeln(sprintf(
+                        '<info>Screenshot "%s" is as expected.</info>',
+                        $event->getArgument('screenshot')
+                    ));
+                }
+            );
+        }
+
+        $this->eventDispatcher->addListener(
+            'service.screenshot.isDifferent',
+            function (GenericEvent $event) use ($output) {
+                $output->writeln(sprintf(
+                    '<error>Screenshot "%s" is different, created diff at "%s".</error>',
+                    $event->getArgument('screenshot'),
+                    $event->getArgument('diff')
+                ));
+            }
+        );
+
+        $this->eventDispatcher->addListener(
+            'service.screenshot.error',
+            function (GenericEvent $event) use ($output) {
+                $output->writeln(sprintf(
+                    '<error>"%s"</error>',
+                    $event->getArgument('e')->getMessage()
+                ));
+            }
+        );
     }
 }

src/Command/CreateBaseCommand.php

@@ -21,23 +21,38 @@ namespace Codappix\WebsiteComparison\Command;
  * 02110-1301, USA.
  */
 
-use Codappix\WebsiteComparison\Service\ScreenshotCrawlerService;
+use Codappix\WebsiteComparison\Service\Screenshot\CrawlerService;
-use Facebook\WebDriver\Chrome\ChromeDriver;
+use Codappix\WebsiteComparison\Service\Screenshot\Service;
-use Facebook\WebDriver\Chrome\ChromeDriverService;
+use Facebook\WebDriver\Remote\RemoteWebDriver;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
-use Symfony\Component\Process\Exception\ProcessFailedException;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
-use Symfony\Component\Process\Process;
+use Symfony\Component\EventDispatcher\GenericEvent;
 
 class CreateBaseCommand extends Command
 {
     /**
-     * @var Process
+     * @var EventDispatcherInterface
      */
-    protected $chromeProcess;
+    protected $eventDispatcher;
+
+    /**
+     * @var RemoteWebDriver
+     */
+    protected $webDriver;
+
+    public function __construct(
+        EventDispatcherInterface $eventDispatcher,
+        RemoteWebDriver $webDriver
+    ) {
+        parent::__construct(null);
+
+        $this->eventDispatcher = $eventDispatcher;
+        $this->webDriver = $webDriver;
+    }
 
     protected function configure()
     {
@@ -71,28 +86,45 @@ class CreateBaseCommand extends Command
 
     protected function execute(InputInterface $input, OutputInterface $output)
     {
-        $screenshotCrawler = new ScreenshotCrawlerService(
+        $this->registerEvents($output);
-            $output,
+
-            $this->getDriver(),
+        $screenshotService = new Service(
-            $input->getArgument('baseUrl'),
+            $this->eventDispatcher,
             $input->getOption('screenshotDir'),
             $input->getOption('screenshotWidth')
         );
+
+        $screenshotCrawler = new CrawlerService(
+            $this->webDriver,
+            $screenshotService,
+            $input->getArgument('baseUrl')
+        );
         $screenshotCrawler->crawl();
     }
 
-    protected function getDriver(): ChromeDriver
+    protected function registerEvents(OutputInterface $output)
     {
-        $chromeDriverService = new ChromeDriverService(
+        if ($output->isVerbose()) {
-            '/usr/lib/chromium-browser/chromedriver',
+            $this->eventDispatcher->addListener(
-            9515,
+                'service.screenshot.created',
-            [
+                function (GenericEvent $event) use ($output) {
-                '--port=9515',
+                    $output->writeln(sprintf(
-                '--headless',
+                        '<info>Created screenshot "%s" for url "%s".</info>',
-            ]
+                        $event->getArgument('screenshot'),
+                        $event->getArgument('url')
+                    ));
+                }
             );
-        $driver = ChromeDriver::start(null, $chromeDriverService);
+        }
 
-        return $driver;
+        $this->eventDispatcher->addListener(
+            'screenshot.service.error',
+            function (GenericEvent $event) use ($output) {
+                $output->writeln(sprintf(
+                    '<error>"%s"</error>',
+                    $event->getArgument('e')->getMessage()
+                ));
+            }
+        );
     }
 }

src/Service/Screenshot/CompareService.php

@@ -0,0 +1,152 @@
+<?php
+
+namespace Codappix\WebsiteComparison\Service\Screenshot;
+
+/*
+ * Copyright (C) 2018 Daniel Siepmann <coding@daniel-siepmann.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\GenericEvent;
+
+class CompareService
+{
+    /**
+     * @var EventDispatcherInterface
+     */
+    protected $eventDispatcher;
+
+    /**
+     * @var Service
+     */
+    protected $screenshotService;
+
+    /**
+     * @var string
+     */
+    protected $compareDirectory = '';
+
+    /**
+     * @var string
+     */
+    protected $diffResultDir = '';
+
+    /**
+     * @var bool
+     */
+    protected $hasDifferences = false;
+
+    public function __construct(
+        EventDispatcherInterface $eventDispatcher,
+        Service $screenshotService,
+        string $compareDirectory,
+        string $diffResultDir
+    ) {
+        $this->eventDispatcher = $eventDispatcher;
+        $this->screenshotService = $screenshotService;
+        $this->compareDirectory = $this->screenshotService->convertReltiveFolder($compareDirectory);
+        $this->diffResultDir = $this->screenshotService->convertReltiveFolder($diffResultDir);
+    }
+
+    public function hasDifferences(): bool
+    {
+        return $this->hasDifferences;
+    }
+
+    public function compareScreenshot(string $screenshot)
+    {
+        try {
+            if ($this->doScreenshotsDiffer($screenshot)) {
+                $this->eventDispatcher->dispatch(
+                    'service.screenshot.isDifferent',
+                    new GenericEvent('New Screenshot is different then base version.', [
+                        'screenshot' => $screenshot,
+                        'diff' => $this->getDiffFileName($screenshot)
+                    ])
+                );
+                return;
+            }
+        } catch (\ImagickException $e) {
+            $this->eventDispatcher->dispatch(
+                'service.screenshot.error',
+                new GenericEvent($e->getMessage(), [$e])
+            );
+            return;
+        }
+
+        $this->eventDispatcher->dispatch(
+            'service.screenshot.isSame',
+            new GenericEvent('New Screenshot is the same as base version.', [
+                'screenshot' => $screenshot,
+            ])
+        );
+    }
+
+    protected function doScreenshotsDiffer(string $screenshot): bool
+    {
+        $actualScreenshot = new \Imagick($screenshot);
+        $actualGeometry = $actualScreenshot->getImageGeometry();
+        $compareScreenshot = new \Imagick($this->getBaseScreenshot($screenshot));
+        $compareGeometry = $compareScreenshot->getImageGeometry();
+
+        if ($actualGeometry !== $compareGeometry) {
+            throw new \ImagickException(sprintf(
+                "Screenshots don't have an equal geometry. Should be %sx%s but is %sx%s",
+                $compareGeometry['width'],
+                $compareGeometry['height'],
+                $actualGeometry['width'],
+                $actualGeometry['height']
+            ));
+        }
+
+        $result = $actualScreenshot->compareImages(
+            $compareScreenshot,
+            \Imagick::METRIC_ROOTMEANSQUAREDERROR
+        );
+        if ($result[1] > 0) {
+            /** @var \Imagick $diffScreenshot */
+            $diffScreenshot = $result[0];
+            $diffScreenshot->setImageFormat('png');
+            $fileName = $this->getDiffFileName($screenshot);
+            $this->screenshotService->createDir(dirname($fileName));
+            file_put_contents($fileName, $diffScreenshot);
+
+            return true;
+        }
+
+        return false;
+    }
+
+    protected function getBaseScreenshot(string $compareScreenshot): string
+    {
+        return str_replace(
+            $this->screenshotService->getScreenshotDir(),
+            $this->compareDirectory,
+            $compareScreenshot
+        );
+    }
+
+    protected function getDiffFileName(string $screenshot): string
+    {
+        return str_replace(
+            $this->screenshotService->getScreenshotDir(),
+            $this->diffResultDir,
+            $screenshot
+        );
+    }
+}

src/Service/Screenshot/CrawlerService.php

@@ -0,0 +1,123 @@
+<?php
+
+namespace Codappix\WebsiteComparison\Service\Screenshot;
+
+/*
+ * Copyright (C) 2018 Daniel Siepmann <coding@daniel-siepmann.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use Codappix\WebsiteComparison\Model\UrlListDto;
+use Facebook\WebDriver\Remote\RemoteWebDriver;
+use Facebook\WebDriver\Remote\RemoteWebElement;
+use Facebook\WebDriver\WebDriverBy;
+use GuzzleHttp\Psr7\Uri;
+
+class CrawlerService
+{
+    /**
+     * @var RemoteWebDriver
+     */
+    protected $driver;
+
+    /**
+     * @var Service
+     */
+    protected $screenshotService;
+
+    /**
+     * @var string
+     */
+    protected $baseUrl = '';
+
+    public function __construct(
+        RemoteWebDriver $driver,
+        Service $screenshotService,
+        string $baseUrl
+    ) {
+        $this->driver = $driver;
+        $this->screenshotService = $screenshotService;
+        $this->baseUrl = rtrim($baseUrl, '/') . '/';
+    }
+
+    public function crawl()
+    {
+        $linkList = new UrlListDto();
+        $linkList->addUrl($this->baseUrl);
+
+        while ($url = $linkList->getNextUrl()) {
+            $this->driver->get($url);
+            $screenshotHeight = $this->driver->findElement(WebDriverBy::cssSelector('body'))
+                ->getSize()
+                ->getHeight();
+            $this->screenshotService->createScreenshot(
+                $this->driver->getCurrentURL(),
+                $screenshotHeight
+            );
+
+            $linkList->markUrlAsFinished($url);
+            array_map([$linkList, 'addUrl'], $this->fetchFurtherLinks(
+                $this->driver->findElements(WebDriverBy::cssSelector('a'))
+            ));
+        }
+    }
+
+    protected function fetchFurtherLinks(array $webElements): array
+    {
+        $links = [];
+        foreach ($webElements as $webElement) {
+            try {
+                $link = $this->fetchLinkFromElement($webElement);
+            } catch (\Exception $e) {
+                continue;
+            }
+
+            $links[] = $link;
+        }
+
+        return $links;
+    }
+
+    protected function fetchLinkFromElement(RemoteWebElement $element): string
+    {
+        $uri = null;
+        $href = $element->getAttribute('href');
+        if (is_string($href)) {
+            $uri = new Uri($href);
+        }
+
+        if ($uri === null) {
+            throw new \Exception('Did not get a Uri for element.', 1535530859);
+        }
+
+        if ($this->isInternalLink($uri)) {
+            return (string) $uri;
+        }
+
+        throw new \Exception('Was external link.', 1535639056);
+    }
+
+    protected function isInternalLink(Uri $uri): bool
+    {
+        $validHosts = [
+            '',
+            (new Uri($this->baseUrl))->getHost(),
+        ];
+
+        return in_array($uri->getHost(), $validHosts);
+    }
+}

src/Service/Screenshot/Service.php

@@ -0,0 +1,132 @@
+<?php
+
+namespace Codappix\WebsiteComparison\Service\Screenshot;
+
+/*
+ * Copyright (C) 2018 Daniel Siepmann <coding@daniel-siepmann.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use GuzzleHttp\Psr7\Uri;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\EventDispatcher\GenericEvent;
+use Symfony\Component\Process\Process;
+
+class Service
+{
+    /**
+     * @var EventDispatcherInterface
+     */
+    protected $eventDispatcher;
+
+    /**
+     * @var string
+     */
+    protected $screenshotDir = '';
+
+    /**
+     * @var int
+     */
+    protected $screenshotWidth = 3840;
+
+    public function __construct(
+        EventDispatcherInterface $eventDispatcher,
+        string $screenshotDir,
+        int $screenshotWidth
+    ) {
+        $this->eventDispatcher = $eventDispatcher;
+        $this->screenshotDir = $this->convertReltiveFolder($screenshotDir);
+        $this->screenshotWidth = $screenshotWidth;
+    }
+
+    public function createScreenshot(string $url, int $height): string
+    {
+        // TODO: Include width in screenshot dir.
+        // This enables to compare different resolutions
+        $screenshotTarget = $this->getScreenshotTarget($url);
+        $this->createDir($this->screenshotDir . dirname($screenshotTarget));
+        $completeScreenshotTarget = $this->screenshotDir . $screenshotTarget;
+
+        $screenshotProcess = new Process([
+            'chromium-browser',
+            '--headless',
+            '--disable-gpu',
+            '--window-size=' . $this->screenshotWidth . ',' . $height,
+            '--screenshot=' . $completeScreenshotTarget,
+            $url
+        ]);
+        // TODO: Check for success
+        $screenshotProcess->run();
+
+        $this->eventDispatcher->dispatch(
+            'service.screenshot.created',
+            new GenericEvent('Created Screenshot', [
+                'screenshot' => $completeScreenshotTarget,
+                'url' => $url,
+            ])
+        );
+
+        return $completeScreenshotTarget;
+    }
+
+    protected function getScreenshotTarget(string $url): string
+    {
+        $uri = new Uri($url);
+
+        return implode(
+            DIRECTORY_SEPARATOR,
+            array_filter(
+                [
+                    $uri->getScheme(),
+                    $uri->getHost(),
+                    trim($uri->getPath(), '/'),
+                    $uri->getQuery(),
+                ],
+                function (string $string) {
+                    return trim($string, ' /') !== '';
+                }
+            )
+        ) . '.png';
+    }
+
+    public function getScreenshotDir(): string
+    {
+        return $this->screenshotDir;
+    }
+
+    /**
+     * @throws \Exception If folder could not be created.
+     */
+    public function createDir(string $dir)
+    {
+        if (!is_dir($dir)) {
+            mkdir($dir, 0777, true);
+        }
+
+        if (!is_dir($dir)) {
+            throw new \Exception('Could not create directory: "' . $dir . '".', 1535528875);
+        }
+    }
+
+    public function convertReltiveFolder(string $folder): string
+    {
+        return implode(DIRECTORY_SEPARATOR, [
+            dirname(dirname(dirname(dirname(__FILE__)))),
+            rtrim($folder, '/'),
+        ]) . DIRECTORY_SEPARATOR;
+    }
+}

src/Service/ScreenshotCrawlerService.php

@@ -1,311 +0,0 @@
-<?php
-
-namespace Codappix\WebsiteComparison\Service;
-
-/*
- * Copyright (C) 2018 Daniel Siepmann <coding@daniel-siepmann.de>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- */
-
-use Codappix\WebsiteComparison\Model\UrlListDto;
-use Facebook\WebDriver\Remote\RemoteWebDriver;
-use Facebook\WebDriver\Remote\RemoteWebElement;
-use Facebook\WebDriver\WebDriverBy;
-use GuzzleHttp\Psr7\Uri;
-use Symfony\Component\Console\Output\OutputInterface;
-use Symfony\Component\Process\Process;
-
-/**
- *
- */
-class ScreenshotCrawlerService
-{
-    /**
-     * @var OutputInterface
-     */
-    protected $output;
-
-    /**
-     * @var RemoteWebDriver
-     */
-    protected $driver;
-
-    /**
-     * @var string
-     */
-    protected $baseUrl = '';
-
-    /**
-     * @var string
-     */
-    protected $screenshotDir = '';
-
-    /**
-     * @var int
-     */
-    protected $screenshotWidth = 3840;
-
-    /**
-     * @var string
-     */
-    protected $compareDirectory = '';
-
-    /**
-     * @var string
-     */
-    protected $diffResultDir = '';
-
-    /**
-     * @var bool
-     */
-    protected $hasDifferences = false;
-
-    public function __construct(
-        OutputInterface $output,
-        RemoteWebDriver $driver,
-        string $baseUrl,
-        string $screenshotDir = 'output/',
-        int $screenshotWidth = 3840
-    ) {
-        $this->output = $output;
-        $this->driver = $driver;
-        $this->baseUrl = rtrim($baseUrl, '/') . '/';
-        $this->screenshotDir = $this->convertReltiveFolder($screenshotDir);
-        $this->screenshotWidth = $screenshotWidth;
-    }
-
-    public function crawl()
-    {
-        $this->createDir($this->screenshotDir);
-
-        $linkList = new UrlListDto();
-        $linkList->addUrl($this->baseUrl);
-
-        while ($url = $linkList->getNextUrl()) {
-            $this->driver->get($url);
-            $screenshotHeight = $this->driver->findElement(WebDriverBy::cssSelector('body'))
-                ->getSize()
-                ->getHeight();
-            $createdScreenshot = $this->createScreenshot($this->driver->getCurrentURL(), $screenshotHeight);
-
-            if ($this->compareDirectory !== '') {
-                $this->compareScreenshot($createdScreenshot);
-            }
-
-            $linkList->markUrlAsFinished($url);
-            array_map([$linkList, 'addUrl'], $this->fetchFurtherLinks(
-                $this->driver->findElements(WebDriverBy::cssSelector('a'))
-            ));
-        }
-    }
-
-    public function compare(string $compareDirectory, string $diffResultDir): bool
-    {
-        // TODO: Check for existence of directory
-        $this->compareDirectory = $this->convertReltiveFolder($compareDirectory);
-        $this->diffResultDir = $this->convertReltiveFolder($diffResultDir);
-        $this->crawl();
-
-        return $this->hasDifferences;
-    }
-
-    /**
-     * @throws \Exception If folder could not be created.
-     */
-    protected function createDir(string $dir)
-    {
-        if (!is_dir($dir)) {
-            mkdir($dir, 0777, true);
-        }
-
-        if (!is_dir($dir)) {
-            throw new \Exception('Could not create directory: "' . $dir . '".', 1535528875);
-        }
-    }
-
-    protected function createScreenshot(string $url, int $height): string
-    {
-        // TODO: Include width in screenshot dir.
-        // This enables to compare different resolutions
-        $screenshotTarget = $this->getScreenshotTarget($url);
-        $this->createDir($this->screenshotDir . dirname($screenshotTarget));
-        $completeScreenshotTarget = $this->screenshotDir . $screenshotTarget;
-
-        $screenshotProcess = new Process([
-            'chromium-browser',
-            '--headless',
-            '--disable-gpu',
-            '--window-size=' . $this->screenshotWidth . ',' . $height,
-            '--screenshot=' . $completeScreenshotTarget,
-            $url
-        ]);
-        // TODO: Check for success
-        $screenshotProcess->run();
-
-        if ($this->output->isVerbose()) {
-            $this->output->writeln(sprintf(
-                '<info>Created screenshot "%s" for url "%s".</info>',
-                $completeScreenshotTarget,
-                $url
-            ));
-        }
-
-        return $completeScreenshotTarget;
-    }
-
-    protected function compareScreenshot(string $screenshot)
-    {
-        try {
-            if ($this->doScreenshotsDiffer($screenshot)) {
-                $this->hasDifferences = true;
-                $this->output->writeln(sprintf(
-                    '<error>Screenshot "%s" is different then "%s". Diff was written to "%s".</error>',
-                    $screenshot,
-                    $this->getBaseScreenshot($screenshot),
-                    $this->getDiffFileName($screenshot)
-                ));
-                return;
-            }
-        } catch (\ImagickException $e) {
-            $this->output->writeln('<error>' . $e->getMessage() . '</error>');
-            return;
-        }
-
-        if ($this->output->isVerbose()) {
-            $this->output->writeln('<info>Screenshot is same.</info>');
-        }
-    }
-
-    protected function doScreenshotsDiffer(string $screenshot): bool
-    {
-        $actualScreenshot = new \Imagick($screenshot);
-        $actualGeometry = $actualScreenshot->getImageGeometry();
-        $compareScreenshot = new \Imagick($this->getBaseScreenshot($screenshot));
-        $compareGeometry = $compareScreenshot->getImageGeometry();
-
-        if ($actualGeometry !== $compareGeometry) {
-            throw new \ImagickException(sprintf(
-                "Screenshots don't have an equal geometry. Should be %sx%s but is %sx%s",
-                $compareGeometry['width'],
-                $compareGeometry['height'],
-                $actualGeometry['width'],
-                $actualGeometry['height']
-            ));
-        }
-
-        $result = $actualScreenshot->compareImages($compareScreenshot, \Imagick::METRIC_ROOTMEANSQUAREDERROR);
-        if ($result[1] > 0) {
-            /** @var \Imagick $diffScreenshot */
-            $diffScreenshot = $result[0];
-            $diffScreenshot->setImageFormat('png');
-            $fileName = $this->getDiffFileName($screenshot);
-            $this->createDir(dirname($fileName));
-            file_put_contents($fileName, $diffScreenshot);
-
-            return true;
-        }
-
-        return false;
-    }
-
-    protected function getBaseScreenshot(string $compareScreenshot): string
-    {
-        return str_replace(
-            $this->screenshotDir,
-            $this->compareDirectory,
-            $compareScreenshot
-        );
-    }
-
-    protected function getScreenshotTarget(string $url)
-    {
-        $uri = new Uri($url);
-
-        return implode(
-            DIRECTORY_SEPARATOR,
-            array_filter(
-                [
-                    $uri->getScheme(),
-                    $uri->getHost(),
-                    trim($uri->getPath(), '/'),
-                    $uri->getQuery(),
-                ],
-                function (string $string) {
-                    return trim($string, ' /') !== '';
-                }
-            )
-        ) . '.png';
-    }
-
-    protected function fetchFurtherLinks(array $webElements): array
-    {
-        $links = [];
-        foreach ($webElements as $webElement) {
-            try {
-                $link = $this->fetchLinkFromElement($webElement);
-            } catch (\Exception $e) {
-                continue;
-            }
-
-            $links[] = $link;
-        }
-
-        return $links;
-    }
-
-    protected function fetchLinkFromElement(RemoteWebElement $element): string
-    {
-        $uri = null;
-        $href = $element->getAttribute('href');
-        if (is_string($href)) {
-            $uri = new Uri($href);
-        }
-
-        if ($uri === null) {
-            throw new \Exception('Did not get a Uri for element.', 1535530859);
-        }
-
-        if ($this->isInternalLink($uri)) {
-            return (string) $uri;
-        }
-
-        throw new \Exception('Was external link.', 1535639056);
-    }
-
-    protected function isInternalLink(Uri $uri): bool
-    {
-        $validHosts = [
-            '',
-            (new Uri($this->baseUrl))->getHost(),
-        ];
-
-        return in_array($uri->getHost(), $validHosts);
-    }
-
-    protected function convertReltiveFolder(string $folder): string
-    {
-        return implode(DIRECTORY_SEPARATOR, [
-            dirname(dirname(dirname(__FILE__))),
-            rtrim($folder, '/'),
-        ]) . DIRECTORY_SEPARATOR;
-    }
-
-    protected function getDiffFileName(string $screenshot): string
-    {
-        return str_replace($this->screenshotDir, $this->diffResultDir, $screenshot);
-    }
-}