class RendererTestBase

abstract class RendererTestBase extends UnitTestCase {
    
    /**
     * The tested renderer.
     *
     * @var \Drupal\Core\Render\Renderer
     */
    protected $renderer;
    
    /**
     * The tested render cache.
     *
     * @var \Drupal\Core\Render\PlaceholderingRenderCache
     */
    protected $renderCache;
    
    /**
     * The tested placeholder generator.
     *
     * @var \Drupal\Core\Render\PlaceholderGenerator
     */
    protected $placeholderGenerator;
    
    /**
     * @var \Symfony\Component\HttpFoundation\RequestStack
     */
    protected $requestStack;
    
    /**
     * @var \Drupal\Core\Cache\CacheFactoryInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $cacheFactory;
    
    /**
     * @var \Drupal\Core\Cache\Context\CacheContextsManager|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $cacheContexts;
    
    /**
     * The mocked controller resolver.
     *
     * @var \Drupal\Core\Controller\ControllerResolverInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $controllerResolver;
    
    /**
     * The mocked theme manager.
     *
     * @var \Drupal\Core\Theme\ThemeManagerInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $themeManager;
    
    /**
     * The mocked element info.
     *
     * @var \Drupal\Core\Render\ElementInfoManagerInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $elementInfo;
    
    /**
     * @var \Drupal\Core\Cache\CacheBackendInterface
     */
    protected $memoryCache;
    
    /**
     * The simulated "current" user role, for use in tests with cache contexts.
     *
     * @var string
     */
    protected $currentUserRole;
    
    /**
     * The mocked renderer configuration.
     *
     * @var array
     */
    protected $rendererConfig = [
        'required_cache_contexts' => [
            'languages:language_interface',
            'theme',
        ],
        'auto_placeholder_conditions' => [
            'max-age' => 0,
            'contexts' => [
                'session',
                'user',
            ],
            'tags' => [
                'current-temperature',
            ],
        ],
    ];
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() {
        parent::setUp();
        $this->controllerResolver = $this->createMock('Drupal\\Core\\Controller\\ControllerResolverInterface');
        $this->themeManager = $this->createMock('Drupal\\Core\\Theme\\ThemeManagerInterface');
        $this->elementInfo = $this->createMock('Drupal\\Core\\Render\\ElementInfoManagerInterface');
        $this->elementInfo
            ->expects($this->any())
            ->method('getInfo')
            ->willReturnCallback(function ($type) {
            switch ($type) {
                case 'details':
                    $info = [
                        '#theme_wrappers' => [
                            'details',
                        ],
                    ];
                    break;
                case 'link':
                    $info = [
                        '#theme' => 'link',
                    ];
                    break;
                default:
                    $info = [];
            }
            $info['#defaults_loaded'] = TRUE;
            return $info;
        });
        $this->requestStack = new RequestStack();
        $request = new Request();
        $request->server
            ->set('REQUEST_TIME', $_SERVER['REQUEST_TIME']);
        $this->requestStack
            ->push($request);
        $this->cacheFactory = $this->createMock('Drupal\\Core\\Cache\\CacheFactoryInterface');
        $this->cacheContextsManager = $this->getMockBuilder('Drupal\\Core\\Cache\\Context\\CacheContextsManager')
            ->disableOriginalConstructor()
            ->getMock();
        $this->cacheContextsManager
            ->method('assertValidTokens')
            ->willReturn(TRUE);
        $current_user_role =& $this->currentUserRole;
        $this->cacheContextsManager
            ->expects($this->any())
            ->method('convertTokensToKeys')
            ->willReturnCallback(function ($context_tokens) use (&$current_user_role) {
            $keys = [];
            foreach ($context_tokens as $context_id) {
                switch ($context_id) {
                    case 'user.roles':
                        $keys[] = 'r.' . $current_user_role;
                        break;
                    case 'languages:language_interface':
                        $keys[] = 'en';
                        break;
                    case 'theme':
                        $keys[] = 'stark';
                        break;
                    default:
                        $keys[] = $context_id;
                }
            }
            return new ContextCacheKeys($keys, new CacheableMetadata());
        });
        $this->placeholderGenerator = new PlaceholderGenerator($this->rendererConfig);
        $this->renderCache = new PlaceholderingRenderCache($this->requestStack, $this->cacheFactory, $this->cacheContextsManager, $this->placeholderGenerator);
        $this->renderer = new Renderer($this->controllerResolver, $this->themeManager, $this->elementInfo, $this->placeholderGenerator, $this->renderCache, $this->requestStack, $this->rendererConfig);
        $container = new ContainerBuilder();
        $container->set('cache_contexts_manager', $this->cacheContextsManager);
        $container->set('render_cache', $this->renderCache);
        $container->set('renderer', $this->renderer);
        \Drupal::setContainer($container);
    }
    
    /**
     * Generates a random context value for the placeholder tests.
     *
     * The #context array used by the placeholder #lazy_builder callback will
     * generally be used to provide metadata like entity IDs, field machine names,
     * paths, etc. for JavaScript replacement of content or assets. In this test,
     * the #lazy_builder callback PlaceholdersTest::callback() renders the context
     * inside test HTML, so using any random string would sometimes cause random
     * test failures because the test output would be unparseable. Instead, we
     * provide random tokens for replacement.
     *
     * @see PlaceholdersTest::callback()
     * @see https://www.drupal.org/node/2151609
     */
    protected function randomContextValue() {
        $tokens = [
            'llama',
            'alpaca',
            'camel',
            'moose',
            'elk',
        ];
        return $tokens[mt_rand(0, 4)];
    }
    
    /**
     * Sets up a render cache back-end that is asserted to be never used.
     */
    protected function setUpUnusedCache() {
        $this->cacheFactory
            ->expects($this->never())
            ->method('get');
    }
    
    /**
     * Sets up a memory-based render cache back-end.
     */
    protected function setupMemoryCache() {
        $this->memoryCache = $this->memoryCache ?: new MemoryBackend();
        $this->cacheFactory
            ->expects($this->atLeastOnce())
            ->method('get')
            ->with('render')
            ->willReturn($this->memoryCache);
    }
    
    /**
     * Sets up a request object on the request stack.
     *
     * @param string $method
     *   The HTTP method to use for the request. Defaults to 'GET'.
     */
    protected function setUpRequest($method = 'GET') {
        $request = Request::create('/', $method);
        // Ensure that the request time is set as expected.
        $request->server
            ->set('REQUEST_TIME', (int) $_SERVER['REQUEST_TIME']);
        $this->requestStack
            ->push($request);
    }
    
    /**
     * Asserts a render cache item.
     *
     * @param string $cid
     *   The expected cache ID.
     * @param mixed $data
     *   The expected data for that cache ID.
     * @param string $bin
     *   The expected cache bin.
     */
    protected function assertRenderCacheItem($cid, $data, $bin = 'render') {
        $cache_backend = $this->cacheFactory
            ->get($bin);
        $cached = $cache_backend->get($cid);
        $this->assertNotFalse($cached, sprintf('Expected cache item "%s" exists.', $cid));
        if ($cached !== FALSE) {
            $this->assertEquals($data, $cached->data, sprintf('Cache item "%s" has the expected data.', $cid));
            $this->assertSame(Cache::mergeTags($data['#cache']['tags'], [
                'rendered',
            ]), $cached->tags, "The cache item's cache tags also has the 'rendered' cache tag.");
        }
    }

}