function RendererTest::testExecuteInRenderContext

@covers ::executeInRenderContext

File

core/tests/Drupal/Tests/Core/Render/RendererTest.php, line 1132

Class

RendererTest

@coversDefaultClass \Drupal\Core\Render\Renderer[[api-linebreak]] @group Render

Namespace

Code

public function testExecuteInRenderContext() : void {
  $return = $this->renderer
    ->executeInRenderContext(new RenderContext(), function () {
    $fiber_callback = function () {
      // Create a #pre_render callback that renders a render array in
      // isolation. This has its own #pre_render callback that calls
      // Fiber::suspend(). This ensures that suspending a Fiber within
      // multiple nested calls to ::executeInRenderContext() doesn't
      // allow render context to get out of sync. This simulates similar
      // conditions to BigPipe placeholder rendering.
      $fiber_suspend_pre_render = function ($elements) {
        $fiber_suspend = function ($elements) {
          \Fiber::suspend();
          return $elements;
        };
        $build = [
          'foo' => [
            '#markup' => 'foo',
            '#pre_render' => [
              $fiber_suspend,
            ],
          ],
        ];
        $markup = $this->renderer
          ->renderInIsolation($build);
        $elements['#markup'] = $markup;
        return $elements;
      };
      $build = [
        'foo' => [
          '#pre_render' => [
            $fiber_suspend_pre_render,
          ],
        ],
      ];
      return $this->renderer
        ->render($build);
    };
    // Build an array of two fibers that executes the code defined above. This
    // ensures that Fiber::suspend() is called from within two
    // ::renderInIsolation() calls without either having been completed.
    $fibers = [];
    foreach ([
      0,
      1,
    ] as $key) {
      $fibers[] = new \Fiber(static fn() => $fiber_callback());
    }
    while ($fibers) {
      foreach ($fibers as $key => $fiber) {
        if ($fiber->isTerminated()) {
          unset($fibers[$key]);
          continue;
        }
        if ($fiber->isSuspended()) {
          $fiber->resume();
        }
        else {
          $fiber->start();
        }
      }
    }
    return $fiber->getReturn();
  });
  $this->assertEquals(Markup::create('foo'), $return);
}