addressMatches example

foreach ($nodes as $node) {
      $file = File::load($node->file->target_id);
      $this->assertSession()->pageTextContains($file->getFilename());
      $this->assertSession()->linkByHrefExists($file->createFileUrl());
      $this->assertSession()->linkByHrefExists('admin/content/files/usage/' . $file->id());
      $this->assertSession()->linkByHrefExists($file->toUrl('delete-form')->toString());
    }
    // Load the page in a definite order.     $this->drupalGet('admin/content/files', ['query' => ['order' => 'filename', 'sort' => 'asc']]);
    $this->clickLink('Delete');
    $file_uri = File::load(1)->getFileUri();
    $this->assertSession()->addressMatches('#file/1/delete$#');
    $this->assertSession()->pageTextContains('Are you sure you want to delete the file druplicon.txt?');
    $this->assertFileExists($file_uri);
    $this->assertSession()->buttonExists('Delete')->press();
    $this->assertSession()->pageTextContains('The file druplicon.txt has been deleted.');
    $this->assertFileDoesNotExist($file_uri);
  }

  /** * Tests file listing usage page for entities with no canonical link template. */
  public function testFileListingUsageNoLink() {