Behat context for working with files in Drupal 8.

File Context

<?php

use Behat\Gherkin\Node\PyStringNode;
use Behat\Mink\Element\NodeElement;
use Behat\Mink\Mink;
use Behat\MinkExtension\Context\MinkAwareContext;

/**
 * Class FileContext.
 */
class FileContext implements MinkAwareContext {

  /**
   * Files created by this context.
   *
   * @var \Drupal\file\Entity\File[]
   */
  protected $files = [];

  /**
   * Mink parameters.
   *
   * @var \Behat\Mink\Mink
   */
  protected $mink;

  /**
   * Mink instance.
   *
   * @var array
   */
  protected $minkParameters = [];

  /**
   * Working dir for the Behat process.
   *
   * @var string
   */
  protected $workingDir;

  /**
   * Prepares test folders in the temporary directory.
   *
   * @BeforeScenario
   */
  public function prepare() {
    $this->workingDir = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'behat' . DIRECTORY_SEPARATOR . md5(microtime() * rand(0, 10000));
  }

  /**
   * Prepares test folders in the temporary directory.
   *
   * @AfterScenario
   */
  public function cleanup() {
    foreach ($this->files as $file) {
      $file->delete();
    }
    $this->files = [];
  }

  /**
   * {@inheritdoc}
   */
  public function setMink(Mink $mink) {
    $this->mink = $mink;
  }

  /**
   * {@inheritdoc}
   */
  public function setMinkParameters(array $parameters) {
    $this->minkParameters = $parameters;
  }

  /**
   * Creates a file with specified name and context in current workdir.
   *
   * @Given /^(?:there is )?a file named "([^"]*)" with:$/
   *
   * @param string $filename
   *   Name of the file (relative path)
   * @param PyStringNode $content
   *   File content.
   */
  public function assertFileNamed($filename, PyStringNode $content) {
    $content = strtr((string) $content, array("'''" => '"""'));
    $this->createFile($this->workingDir . '/' . $filename, $content);
  }

  /**
   * Create a file.
   *
   * @param string $filename
   *   Name of the file.
   * @param string $content
   *   File content.
   */
  private function createFile($filename, $content) {
    $path = dirname($filename);
    if (!is_dir($path)) {
      mkdir($path, 0777, true);
    }

    file_put_contents($filename, $content);
  }

  /**
   * Selects files for entity browser.
   *
   * @When I select :file entity for :field
   * @When I select :file entity for :field with alt :alt
   * @When I select :file entity for :field with description :desc
   */
  public function assertEntityFromFile($file, $field, $alt = NULL, $desc = NULL) {
    // Unfortunately ::findField does not seem to work on hidden inputs, so
    // we'll look for the input by name.
    $name = $field . '[target_id]';
    $fieldEl = $this->mink->getSession()->getPage()->find('css', 'input[name="' . $name . '"]');
    if (!$fieldEl) {
      throw new \Exception(sprintf('Unable to find field "%s".', $field));
    }

    // Create an entity for the file.
    $source = $this->workingDir . '/' . $file;
    $dest = "public://behat/$file";
    $dir = dirname($dest);
    file_prepare_directory($dir, FILE_CREATE_DIRECTORY);
    $file = file_save_data(file_get_contents($source), $dest, FILE_EXISTS_RENAME);
    if (!$file) {
      throw new \Exception(sprintf('Unable to save file "%s".', $dest));
    }
    $this->files[] = $file;
    $file->save();

    // Add the entity to the field value.
    $value = array_filter(array_map('trim', explode(' ', $fieldEl->getValue())));
    $value[] = "file:{$file->id()}";
    $fieldEl->setValue(implode(' ', $value));

    $weightName = $field . '[current][' . $file->id() .'][_weight]';
    $weightEl = $this->mink->getSession()->getPage()->find('css', 'input[name="' . $weightName . '"]');

    if ($weightEl) {
      $weightEl->setValue(0);
    }
    else {
      $this->createEntityBrowserInputNode($fieldEl, $weightName, 0);
    }

    // Create the "alt" input if specified.
    if ($alt) {
      $altName = $field . '[current][' . $file->id() .'][meta][alt]';
      $altEl = $this->mink->getSession()->getPage()->find('css', 'input[name="' . $altName . '"]');
      if ($altEl) {
        $altEl->setValue($alt);
      }
      else {
        $this->createEntityBrowserInputNode($fieldEl, $altName, $alt);
      }
    }

    // Create the "desc" input if specified.
    if ($desc) {
      $descName = $field . '[current][' . $file->id() .'][meta][description]';
      $descEl = $this->mink->getSession()->getPage()->find('css', 'input[name="' . $descName . '"]');
      if ($descEl) {
        $descEl->setValue($desc);
      }
      else {
        $this->createEntityBrowserInputNode($fieldEl, $descName, $desc);
      }
    }
  }

  /**
   * Inserts a DOMNode into the form to mimic entity browser input.
   *
   * Likely only works when utilizing the GoutteDriver.
   *
   * @param \Behat\Mink\Element\NodeElement $fieldEl
   *   The entity browser field element.
   * @param string $inputName
   *   The name of the node.
   * @param string $value
   *   The value to set on the node.
   */
  protected function createEntityBrowserInputNode(NodeElement $fieldEl, $inputName, $value) {
    /** @var \Behat\Mink\Driver\GoutteDriver $driver */
    $driver = $this->mink->getSession()->getDriver();
    $client = $driver->getClient();
    $crawler = $client->getCrawler();
    /** @var \DOMDocument $doc */
    $doc = $crawler->getNode(0)->ownerDocument;
    $node = $doc->createElement('input');
    $node->setAttribute('type', 'hidden');
    $node->setAttribute('name', $inputName);
    $node->setAttribute('value', $value);
    $query = new \DOMXPath($doc);
    $result = $query->query($fieldEl->getXpath())->item(0);
    $result->insertBefore($node);
  }

  /**
   * Produces a Fill Murray placeholder image.
   *
   * @param string $size
   *   Size of the image in pixels, ie. "800 , 600".
   *
   * @Given there is a Fill Murray image :size
   */
  public function assertFillMurray($size) {
    $dimensions = array_map('trim', explode(',', $size));
    $fileName = 'fm_' . implode('_', $dimensions) . '.jpg';

    // Check temp space, to avoid re-downloading on subsequent scenarios.
    $temp = '/tmp/behat/fm/' . $fileName;
    if (!file_exists($temp)) {
      $dir = dirname($temp);
      if (!is_dir($dir)) {
        @mkdir($dir, 0777, TRUE);
      }
      $url = 'https://www.fillmurray.com/' . implode('/', $dimensions);
      $contents = file_get_contents($url);
      file_put_contents($temp, $contents);
    }

    $contents = file_get_contents($temp);
    $this->createFile($this->workingDir . '/' . $fileName, $contents);
  }

}