class BlockViewBuilderTest

class BlockViewBuilderTest extends KernelTestBase {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'block',
    'block_test',
    'system',
    'user',
  ];
  
  /**
   * The block being tested.
   *
   * @var \Drupal\block\BlockInterface
   */
  protected $block;
  
  /**
   * The block storage.
   *
   * @var \Drupal\Core\Config\Entity\ConfigEntityStorageInterface
   */
  protected $controller;
  
  /**
   * The renderer.
   *
   * @var \Drupal\Core\Render\RendererInterface
   */
  protected $renderer;
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->container
      ->get('theme_installer')
      ->install([
      'stark',
    ]);
    $this->controller = $this->container
      ->get('entity_type.manager')
      ->getStorage('block');
    \Drupal::keyValue('block_test')->set('content', 'Llamas > unicorns!');
    // Create a block with only required values.
    $this->block = $this->controller
      ->create([
      'id' => 'test_block',
      'theme' => 'stark',
      'plugin' => 'test_cache',
    ]);
    $this->block
      ->save();
    $this->container
      ->get('cache.render')
      ->deleteAll();
    $this->renderer = $this->container
      ->get('renderer');
  }
  
  /**
   * Tests the rendering of blocks.
   */
  public function testBasicRendering() : void {
    \Drupal::keyValue('block_test')->set('content', '');
    $entity = $this->controller
      ->create([
      'id' => 'test_block1',
      'theme' => 'stark',
      'plugin' => 'test_html',
    ]);
    $entity->save();
    // Test the rendering of a block.
    $entity = Block::load('test_block1');
    $builder = \Drupal::entityTypeManager()->getViewBuilder('block');
    $output = $builder->view($entity, 'block');
    $expected = [];
    $expected[] = '<div id="block-test-block1">';
    $expected[] = '  ';
    $expected[] = '    ';
    $expected[] = '      ';
    $expected[] = '  </div>';
    $expected[] = '';
    $expected_output = implode("\n", $expected);
    $this->assertSame($expected_output, (string) $this->renderer
      ->renderRoot($output));
    // Reset the HTML IDs so that the next render is not affected.
    Html::resetSeenIds();
    // Test the rendering of a block with a given title.
    $entity = $this->controller
      ->create([
      'id' => 'test_block2',
      'theme' => 'stark',
      'plugin' => 'test_html',
      'settings' => [
        'label' => 'Powered by Bananas',
      ],
    ]);
    $entity->save();
    $output = $builder->view($entity, 'block');
    $expected = [];
    $expected[] = '<div id="block-test-block2">';
    $expected[] = '  ';
    $expected[] = '      <h2>Powered by Bananas</h2>';
    $expected[] = '    ';
    $expected[] = '      ';
    $expected[] = '  </div>';
    $expected[] = '';
    $expected_output = implode("\n", $expected);
    $this->assertSame($expected_output, (string) $this->renderer
      ->renderRoot($output));
  }
  
  /**
   * Tests block render cache handling.
   */
  public function testBlockViewBuilderCache() : void {
    // Verify cache handling for a non-empty block.
    $this->verifyRenderCacheHandling();
    // Create an empty block.
    $this->block = $this->controller
      ->create([
      'id' => 'test_block',
      'theme' => 'stark',
      'plugin' => 'test_cache',
    ]);
    $this->block
      ->save();
    \Drupal::keyValue('block_test')->set('content', NULL);
    // Verify cache handling for an empty block.
    $this->verifyRenderCacheHandling();
  }
  
  /**
   * Verifies render cache handling of the block being tested.
   *
   * @see ::testBlockViewBuilderCache()
   */
  protected function verifyRenderCacheHandling() {
    /** @var \Drupal\Core\Cache\VariationCacheFactoryInterface $variation_cache_factory */
    $variation_cache_factory = $this->container
      ->get('variation_cache_factory');
    $cache_bin = $variation_cache_factory->get('render');
    // Force a request via GET so we can test the render cache.
    $request = \Drupal::request();
    $request_method = $request->server
      ->get('REQUEST_METHOD');
    $request->setMethod('GET');
    // Test that a cache entry is created.
    $build = $this->getBlockRenderArray();
    $cache_keys = [
      'entity_view',
      'block',
      'test_block',
    ];
    $this->renderer
      ->renderRoot($build);
    $this->assertNotEmpty($cache_bin->get($cache_keys, CacheableMetadata::createFromRenderArray($build)), 'The block render element has been cached.');
    // Re-save the block and check that the cache entry has been deleted.
    $this->block
      ->save();
    $this->assertFalse($cache_bin->get($cache_keys, CacheableMetadata::createFromRenderArray($build)), 'The block render cache entry has been cleared when the block was saved.');
    // Rebuild the render array (creating a new cache entry in the process) and
    // delete the block to check the cache entry is deleted.
    unset($build['#printed']);
    // Re-add the block because \Drupal\block\BlockViewBuilder::buildBlock()
    // removes it.
    $build['#block'] = $this->block;
    $this->renderer
      ->renderRoot($build);
    $this->assertNotEmpty($cache_bin->get($cache_keys, CacheableMetadata::createFromRenderArray($build)), 'The block render element has been cached.');
    $this->block
      ->delete();
    $this->assertFalse($cache_bin->get($cache_keys, CacheableMetadata::createFromRenderArray($build)), 'The block render cache entry has been cleared when the block was deleted.');
    // Restore the previous request method.
    $request->setMethod($request_method);
  }
  
  /**
   * Tests block view altering.
   *
   * @see hook_block_view_alter()
   * @see hook_block_view_BASE_BLOCK_ID_alter()
   */
  public function testBlockViewBuilderViewAlter() : void {
    // Establish baseline.
    $build = $this->getBlockRenderArray();
    $this->setRawContent((string) $this->renderer
      ->renderRoot($build));
    $this->assertSame('Llamas > unicorns!', trim((string) $this->cssSelect('div')[0]));
    // Enable the block view alter hook that adds a foo=bar attribute.
    \Drupal::state()->set('block_test_view_alter_suffix', TRUE);
    Cache::invalidateTags($this->block
      ->getCacheTagsToInvalidate());
    $build = $this->getBlockRenderArray();
    $this->setRawContent((string) $this->renderer
      ->renderRoot($build));
    $this->assertSame('Llamas > unicorns!', trim((string) $this->cssSelect('[foo=bar]')[0]));
    \Drupal::state()->set('block_test_view_alter_suffix', FALSE);
    \Drupal::keyValue('block_test')->set('content', NULL);
    Cache::invalidateTags($this->block
      ->getCacheTagsToInvalidate());
    // Advanced: cached block, but an alter hook adds a #pre_render callback to
    // alter the eventual content.
    \Drupal::state()->set('block_test_view_alter_append_pre_render_prefix', TRUE);
    $build = $this->getBlockRenderArray();
    $this->assertFalse(isset($build['#prefix']), 'The appended #pre_render callback has not yet run before rendering.');
    $this->assertSame('Hiya!<br>', (string) $this->renderer
      ->renderRoot($build));
    // Check that a cached block without content is altered.
    $this->assertArrayHasKey('#prefix', $build);
    $this->assertSame('Hiya!<br>', $build['#prefix']);
  }
  
  /**
   * Tests block build altering.
   *
   * @see hook_block_build_alter()
   * @see hook_block_build_BASE_BLOCK_ID_alter()
   */
  public function testBlockViewBuilderBuildAlter() : void {
    // Force a request via GET so we can test the render cache.
    $request = \Drupal::request();
    $request_method = $request->server
      ->get('REQUEST_METHOD');
    $request->setMethod('GET');
    $default_keys = [
      'entity_view',
      'block',
      'test_block',
    ];
    $default_contexts = [];
    $default_tags = [
      'block_view',
      'config:block.block.test_block',
    ];
    $default_max_age = Cache::PERMANENT;
    // hook_block_build_alter() adds an additional cache key.
    $alter_add_key = $this->randomMachineName();
    \Drupal::state()->set('block_test_block_alter_cache_key', $alter_add_key);
    $this->assertBlockRenderedWithExpectedCacheability(array_merge($default_keys, [
      $alter_add_key,
    ]), $default_contexts, $default_tags, $default_max_age);
    \Drupal::state()->set('block_test_block_alter_cache_key', NULL);
    // hook_block_build_alter() adds an additional cache context.
    $alter_add_context = 'url.query_args:' . $this->randomMachineName();
    \Drupal::state()->set('block_test_block_alter_cache_context', $alter_add_context);
    $this->assertBlockRenderedWithExpectedCacheability($default_keys, Cache::mergeContexts($default_contexts, [
      $alter_add_context,
    ]), $default_tags, $default_max_age);
    \Drupal::state()->set('block_test_block_alter_cache_context', NULL);
    // hook_block_build_alter() adds an additional cache tag.
    $alter_add_tag = $this->randomMachineName();
    \Drupal::state()->set('block_test_block_alter_cache_tag', $alter_add_tag);
    $this->assertBlockRenderedWithExpectedCacheability($default_keys, $default_contexts, Cache::mergeTags($default_tags, [
      $alter_add_tag,
    ]), $default_max_age);
    \Drupal::state()->set('block_test_block_alter_cache_tag', NULL);
    // hook_block_build_alter() alters the max-age.
    $alter_max_age = 300;
    \Drupal::state()->set('block_test_block_alter_cache_max_age', $alter_max_age);
    $this->assertBlockRenderedWithExpectedCacheability($default_keys, $default_contexts, $default_tags, $alter_max_age);
    \Drupal::state()->set('block_test_block_alter_cache_max_age', NULL);
    // hook_block_build_alter() alters cache keys, contexts, tags and max-age.
    \Drupal::state()->set('block_test_block_alter_cache_key', $alter_add_key);
    \Drupal::state()->set('block_test_block_alter_cache_context', $alter_add_context);
    \Drupal::state()->set('block_test_block_alter_cache_tag', $alter_add_tag);
    \Drupal::state()->set('block_test_block_alter_cache_max_age', $alter_max_age);
    $this->assertBlockRenderedWithExpectedCacheability(array_merge($default_keys, [
      $alter_add_key,
    ]), Cache::mergeContexts($default_contexts, [
      $alter_add_context,
    ]), Cache::mergeTags($default_tags, [
      $alter_add_tag,
    ]), $alter_max_age);
    \Drupal::state()->set('block_test_block_alter_cache_key', NULL);
    \Drupal::state()->set('block_test_block_alter_cache_context', NULL);
    \Drupal::state()->set('block_test_block_alter_cache_tag', NULL);
    \Drupal::state()->set('block_test_block_alter_cache_max_age', NULL);
    // hook_block_build_alter() sets #create_placeholder.
    foreach ([
      TRUE,
      FALSE,
    ] as $value) {
      \Drupal::state()->set('block_test_block_alter_create_placeholder', $value);
      $build = $this->getBlockRenderArray();
      $this->assertTrue(isset($build['#create_placeholder']));
      $this->assertSame($value, $build['#create_placeholder']);
    }
    \Drupal::state()->set('block_test_block_alter_create_placeholder', NULL);
    // Restore the previous request method.
    $request->setMethod($request_method);
  }
  
  /**
   * Asserts that a block is built/rendered/cached with expected cacheability.
   *
   * @param string[] $expected_keys
   *   The expected cache keys.
   * @param string[] $expected_contexts
   *   The expected cache contexts.
   * @param string[] $expected_tags
   *   The expected cache tags.
   * @param int $expected_max_age
   *   The expected max-age.
   *
   * @internal
   */
  protected function assertBlockRenderedWithExpectedCacheability(array $expected_keys, array $expected_contexts, array $expected_tags, int $expected_max_age) : void {
    /** @var \Drupal\Core\Cache\VariationCacheFactoryInterface $variation_cache_factory */
    $variation_cache_factory = $this->container
      ->get('variation_cache_factory');
    $cache_bin = $variation_cache_factory->get('render');
    $required_cache_contexts = [
      'languages:' . LanguageInterface::TYPE_INTERFACE,
      'theme',
      'user.permissions',
    ];
    // Check that the expected cacheability metadata is present in:
    // - the built render array;
    $build = $this->getBlockRenderArray();
    $this->assertSame($expected_keys, $build['#cache']['keys']);
    $this->assertEqualsCanonicalizing($expected_contexts, $build['#cache']['contexts']);
    $this->assertEqualsCanonicalizing($expected_tags, $build['#cache']['tags']);
    $this->assertSame($expected_max_age, $build['#cache']['max-age']);
    $this->assertFalse(isset($build['#create_placeholder']));
    // - the rendered render array;
    $this->renderer
      ->renderRoot($build);
    // - the render cache item.
    $final_cache_contexts = Cache::mergeContexts($expected_contexts, $required_cache_contexts);
    $cache_item = $cache_bin->get($expected_keys, CacheableMetadata::createFromRenderArray($build));
    $this->assertNotEmpty($cache_item, 'The block render element has been cached with the expected cache keys.');
    $this->assertEqualsCanonicalizing(Cache::mergeTags($expected_tags, [
      'rendered',
    ]), $cache_item->tags);
    $this->assertEqualsCanonicalizing($final_cache_contexts, $cache_item->data['#cache']['contexts']);
    $this->assertEqualsCanonicalizing($expected_tags, $cache_item->data['#cache']['tags']);
    $this->assertSame($expected_max_age, $cache_item->data['#cache']['max-age']);
    $cache_bin->delete($expected_keys, CacheableMetadata::createFromRenderArray($build));
  }
  
  /**
   * Get a fully built render array for a block.
   *
   * @return array
   *   The render array.
   */
  protected function getBlockRenderArray() {
    return $this->container
      ->get('entity_type.manager')
      ->getViewBuilder('block')
      ->view($this->block, 'block');
  }

}