BigPipeStrategy example

$session_configuration = $this->prophesize(SessionConfigurationInterface::class);
    $session_configuration->hasSession(Argument::type(Request::class))
      ->willReturn($request_has_session);

    $route = $this->prophesize(Route::class);
    $route->getOption('_no_big_pipe')
      ->willReturn($route_match_has_no_big_pipe_option);
    $route_match = $this->prophesize(RouteMatchInterface::class);
    $route_match->getRouteObject()
      ->willReturn($route);

    $big_pipe_strategy = new BigPipeStrategy($session_configuration->reveal(), $request_stack->reveal(), $route_match->reveal());
    $processed_placeholders = $big_pipe_strategy->processPlaceholders($placeholders);

    if ($request->isMethodCacheable() && !$route_match_has_no_big_pipe_option && $request_has_session) {
      $this->assertSameSize($expected_big_pipe_placeholders, $processed_placeholders, 'BigPipe is able to deliver all placeholders.');
      foreach (array_keys($placeholders) as $placeholder) {
        $this->assertSame($expected_big_pipe_placeholders[$placeholder], $processed_placeholders[$placeholder], "Verifying how BigPipeStrategy handles the placeholder '$placeholder'");
      }
    }
    else {
      $this->assertCount(0, $processed_placeholders);
    }
  }