class GetRdfNamespacesTest

class GetRdfNamespacesTest extends BrowserTestBase {
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'rdf',
    'rdf_test_namespaces',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * Tests getting RDF namespaces.
   */
  public function testGetRdfNamespaces() {
    // Fetches the front page and extracts RDFa 1.1 prefixes.
    $this->drupalGet('');
    // We have to use the find() method on the driver directly because //html is
    // prepended to all xpath queries otherwise.
    $driver = $this->getSession()
      ->getDriver();
    $element = $driver->find('//html[contains(@prefix, "rdfs: http://www.w3.org/2000/01/rdf-schema#")]');
    $this->assertCount(1, $element, 'A prefix declared once is displayed.');
    $element = $driver->find('//html[contains(@prefix, "foaf: http://xmlns.com/foaf/0.1/")]');
    $this->assertCount(1, $element, 'The same prefix declared in several implementations of hook_rdf_namespaces() is valid as long as all the namespaces are the same.');
    $element = $driver->find('//html[contains(@prefix, "foaf1: http://xmlns.com/foaf/0.1/")]');
    $this->assertCount(1, $element, 'Two prefixes can be assigned the same namespace.');
    $element = $driver->find('//html[contains(@prefix, "dc: http://purl.org/dc/terms/")]');
    $this->assertCount(1, $element, 'When a prefix has conflicting namespaces, the first declared one is used.');
    // Get all RDF namespaces.
    $ns = rdf_get_namespaces();
    $this->assertEquals('http://www.w3.org/2000/01/rdf-schema#', $ns['rdfs'], 'A prefix declared once is included.');
    $this->assertEquals('http://xmlns.com/foaf/0.1/', $ns['foaf'], 'The same prefix declared in several implementations of hook_rdf_namespaces() is valid as long as all the namespaces are the same.');
    $this->assertEquals('http://xmlns.com/foaf/0.1/', $ns['foaf1'], 'Two prefixes can be assigned the same namespace.');
    // Enable rdf_conflicting_namespaces to ensure that an exception is thrown
    // when RDF namespaces are conflicting.
    \Drupal::service('module_installer')->install([
      'rdf_conflicting_namespaces',
    ], TRUE);
    try {
      $ns = rdf_get_namespaces();
      $this->fail('Expected exception not thrown for conflicting namespace declaration.');
    } catch (\Exception $e) {
      // Expected exception; just continue testing.
    }
  }

}