class BlockViewBuilderTest

class BlockViewBuilderTest extends KernelTestBase {
    
    /**
     * Modules to install.
     *
     * @var array
     */
    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::state()->set('block_test.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::state()->set('block_test.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::state()->set('block_test.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) $this->cssSelect('[foo=bar]')[0]));
        \Drupal::state()->set('block_test_view_alter_suffix', FALSE);
        \Drupal::state()->set('block_test.content', NULL);
        Cache::invalidateTags($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');
    }

}