--- /dev/null
+<?php
+
+namespace Drupal\Tests\layout_builder\Unit;
+
+use Drupal\Core\Block\BlockManagerInterface;
+use Drupal\Core\Block\BlockPluginInterface;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\Layout\LayoutInterface;
+use Drupal\Core\Layout\LayoutPluginManagerInterface;
+use Drupal\layout_builder\Event\SectionComponentBuildRenderArrayEvent;
+use Drupal\layout_builder\LayoutBuilderEvents;
+use Drupal\layout_builder\SectionComponent;
+use Drupal\Tests\UnitTestCase;
+use Prophecy\Argument;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+
+/**
+ * @coversDefaultClass \Drupal\layout_builder\SectionComponent
+ * @group layout_builder
+ */
+class SectionComponentTest extends UnitTestCase {
+
+ /**
+ * @covers ::toRenderArray
+ */
+ public function testToRenderArray() {
+ $existing_block = $this->prophesize(BlockPluginInterface::class);
+ $existing_block->getPluginId()->willReturn('block_plugin_id');
+
+ $block_manager = $this->prophesize(BlockManagerInterface::class);
+ $block_manager->createInstance('some_block_id', ['id' => 'some_block_id'])->willReturn($existing_block->reveal());
+
+ // Imitate an event subscriber by setting a resulting build on the event.
+ $event_dispatcher = $this->prophesize(EventDispatcherInterface::class);
+ $event_dispatcher
+ ->dispatch(LayoutBuilderEvents::SECTION_COMPONENT_BUILD_RENDER_ARRAY, Argument::type(SectionComponentBuildRenderArrayEvent::class))
+ ->shouldBeCalled()
+ ->will(function ($args) {
+ /** @var \Drupal\layout_builder\Event\SectionComponentBuildRenderArrayEvent $event */
+ $event = $args[1];
+ $event->setBuild(['#markup' => $event->getPlugin()->getPluginId()]);
+ return;
+ });
+
+ $layout_plugin = $this->prophesize(LayoutInterface::class);
+ $layout_plugin->build(Argument::type('array'))->willReturnArgument(0);
+
+ $layout_manager = $this->prophesize(LayoutPluginManagerInterface::class);
+ $layout_manager->createInstance('layout_onecol', [])->willReturn($layout_plugin->reveal());
+
+ $container = new ContainerBuilder();
+ $container->set('plugin.manager.block', $block_manager->reveal());
+ $container->set('event_dispatcher', $event_dispatcher->reveal());
+ $container->set('plugin.manager.core.layout', $layout_manager->reveal());
+ \Drupal::setContainer($container);
+
+ $expected = [
+ '#cache' => [
+ 'contexts' => [],
+ 'tags' => [],
+ 'max-age' => -1,
+ ],
+ '#markup' => 'block_plugin_id',
+ ];
+
+ $component = new SectionComponent('some-uuid', 'some-region', ['id' => 'some_block_id']);
+ $result = $component->toRenderArray();
+ $this->assertEquals($expected, $result);
+ }
+
+}