class ResourceTestBase

abstract class ResourceTestBase extends BrowserTestBase {
    
    /**
     * The format to use in this test.
     *
     * A format is the combination of a certain normalizer and a certain
     * serializer.
     *
     * @see https://www.drupal.org/developing/api/8/serialization
     *
     * (The default is 'json' because that doesn't depend on any module.)
     *
     * @var string
     */
    protected static $format = 'json';
    
    /**
     * The MIME type that corresponds to $format.
     *
     * (Sadly this cannot be computed automatically yet.)
     *
     * @var string
     */
    protected static $mimeType = 'application/json';
    
    /**
     * The authentication mechanism to use in this test.
     *
     * (The default is 'cookie' because that doesn't depend on any module.)
     *
     * @var string
     */
    protected static $auth = FALSE;
    
    /**
     * The REST Resource Config entity ID under test (i.e. a resource type).
     *
     * The REST Resource plugin ID can be calculated from this.
     *
     * @var string
     *
     * @see \Drupal\rest\Entity\RestResourceConfig::__construct()
     */
    protected static $resourceConfigId = NULL;
    
    /**
     * The account to use for authentication, if any.
     *
     * @var null|\Drupal\Core\Session\AccountInterface
     */
    protected $account = NULL;
    
    /**
     * The REST resource config entity storage.
     *
     * @var \Drupal\Core\Entity\EntityStorageInterface
     */
    protected $resourceConfigStorage;
    
    /**
     * The serializer service.
     *
     * @var \Symfony\Component\Serializer\Serializer
     */
    protected $serializer;
    
    /**
     * Modules to install.
     *
     * @var array
     */
    protected static $modules = [
        'rest',
    ];
    
    /**
     * {@inheritdoc}
     */
    public function setUp() {
        parent::setUp();
        $this->serializer = $this->container
            ->get('serializer');
        // Ensure the anonymous user role has no permissions at all.
        $user_role = Role::load(RoleInterface::ANONYMOUS_ID);
        foreach ($user_role->getPermissions() as $permission) {
            $user_role->revokePermission($permission);
        }
        $user_role->save();
        assert([] === $user_role->getPermissions(), 'The anonymous user role has no permissions at all.');
        if (static::$auth !== FALSE) {
            // Ensure the authenticated user role has no permissions at all.
            $user_role = Role::load(RoleInterface::AUTHENTICATED_ID);
            foreach ($user_role->getPermissions() as $permission) {
                $user_role->revokePermission($permission);
            }
            $user_role->save();
            assert([] === $user_role->getPermissions(), 'The authenticated user role has no permissions at all.');
            // Create an account.
            $this->account = $this->createUser();
        }
        else {
            // Otherwise, also create an account, so that any test involving User
            // entities will have the same user IDs regardless of authentication.
            $this->createUser();
        }
        $this->resourceConfigStorage = $this->container
            ->get('entity_type.manager')
            ->getStorage('rest_resource_config');
        // Ensure there's a clean slate: delete all REST resource config entities.
        $this->resourceConfigStorage
            ->delete($this->resourceConfigStorage
            ->loadMultiple());
        $this->refreshTestStateAfterRestConfigChange();
    }
    
    /**
     * Provisions the REST resource under test.
     *
     * @param string[] $formats
     *   The allowed formats for this resource.
     * @param string[] $authentication
     *   The allowed authentication providers for this resource.
     * @param string[] $methods
     *   The allowed methods for this resource.
     */
    protected function provisionResource($formats = [], $authentication = [], array $methods = [
        'GET',
        'POST',
        'PATCH',
        'DELETE',
    ]) {
        $this->resourceConfigStorage
            ->create([
            'id' => static::$resourceConfigId,
            'granularity' => RestResourceConfigInterface::RESOURCE_GRANULARITY,
            'configuration' => [
                'methods' => $methods,
                'formats' => $formats,
                'authentication' => $authentication,
            ],
            'status' => TRUE,
        ])
            ->save();
        $this->refreshTestStateAfterRestConfigChange();
    }
    
    /**
     * Refreshes the state of the tester to be in sync with the testee.
     *
     * Should be called after every change made to:
     * - RestResourceConfig entities
     */
    protected function refreshTestStateAfterRestConfigChange() {
        // Ensure that the cache tags invalidator has its internal values reset.
        // Otherwise the http_response cache tag invalidation won't work.
        $this->refreshVariables();
        // Tests using this base class may trigger route rebuilds due to changes to
        // RestResourceConfig entities. Ensure the test generates routes using an
        // up-to-date router.
        \Drupal::service('router.builder')->rebuildIfNeeded();
    }
    
    /**
     * Return the expected error message.
     *
     * @param string $method
     *   The HTTP method (GET, POST, PATCH, DELETE).
     *
     * @return string
     *   The error string.
     */
    protected function getExpectedUnauthorizedAccessMessage($method) {
        $resource_plugin_id = str_replace('.', ':', static::$resourceConfigId);
        $permission = 'restful ' . strtolower($method) . ' ' . $resource_plugin_id;
        return "The '{$permission}' permission is required.";
    }
    
    /**
     * Sets up the necessary authorization.
     *
     * In case of a test verifying publicly accessible REST resources: grant
     * permissions to the anonymous user role.
     *
     * In case of a test verifying behavior when using a particular authentication
     * provider: create a user with a particular set of permissions.
     *
     * Because of the $method parameter, it's possible to first set up
     * authentication for only GET, then add POST, et cetera. This then also
     * allows for verifying a 403 in case of missing authorization.
     *
     * @param string $method
     *   The HTTP method for which to set up authentication.
     *
     * @see ::grantPermissionsToAnonymousRole()
     * @see ::grantPermissionsToAuthenticatedRole()
     */
    protected abstract function setUpAuthorization($method);
    
    /**
     * Verifies the error response in case of missing authentication.
     *
     * @param string $method
     *   HTTP method.
     * @param \Psr\Http\Message\ResponseInterface $response
     *   The response to assert.
     */
    protected abstract function assertResponseWhenMissingAuthentication($method, ResponseInterface $response);
    
    /**
     * Asserts normalization-specific edge cases.
     *
     * (Should be called before sending a well-formed request.)
     *
     * @see \GuzzleHttp\ClientInterface::request()
     *
     * @param string $method
     *   HTTP method.
     * @param \Drupal\Core\Url $url
     *   URL to request.
     * @param array $request_options
     *   Request options to apply.
     */
    protected abstract function assertNormalizationEdgeCases($method, Url $url, array $request_options);
    
    /**
     * Asserts authentication provider-specific edge cases.
     *
     * (Should be called before sending a well-formed request.)
     *
     * @see \GuzzleHttp\ClientInterface::request()
     *
     * @param string $method
     *   HTTP method.
     * @param \Drupal\Core\Url $url
     *   URL to request.
     * @param array $request_options
     *   Request options to apply.
     */
    protected abstract function assertAuthenticationEdgeCases($method, Url $url, array $request_options);
    
    /**
     * Returns the expected cacheability of an unauthorized access response.
     *
     * @return \Drupal\Core\Cache\RefinableCacheableDependencyInterface
     *   The expected cacheability.
     */
    protected abstract function getExpectedUnauthorizedAccessCacheability();
    
    /**
     * Initializes authentication.
     *
     * E.g. for cookie authentication, we first need to get a cookie.
     */
    protected function initAuthentication() {
    }
    
    /**
     * Returns Guzzle request options for authentication.
     *
     * @param string $method
     *   The HTTP method for this authenticated request.
     *
     * @return array
     *   Guzzle request options to use for authentication.
     *
     * @see \GuzzleHttp\ClientInterface::request()
     */
    protected function getAuthenticationRequestOptions($method) {
        return [];
    }
    
    /**
     * Grants permissions to the anonymous role.
     *
     * @param string[] $permissions
     *   Permissions to grant.
     */
    protected function grantPermissionsToAnonymousRole(array $permissions) {
        $this->grantPermissions(Role::load(RoleInterface::ANONYMOUS_ID), $permissions);
    }
    
    /**
     * Grants permissions to the authenticated role.
     *
     * @param string[] $permissions
     *   Permissions to grant.
     */
    protected function grantPermissionsToAuthenticatedRole(array $permissions) {
        $this->grantPermissions(Role::load(RoleInterface::AUTHENTICATED_ID), $permissions);
    }
    
    /**
     * Grants permissions to the tested role: anonymous or authenticated.
     *
     * @param string[] $permissions
     *   Permissions to grant.
     *
     * @see ::grantPermissionsToAuthenticatedRole()
     * @see ::grantPermissionsToAnonymousRole()
     */
    protected function grantPermissionsToTestedRole(array $permissions) {
        if (static::$auth) {
            $this->grantPermissionsToAuthenticatedRole($permissions);
        }
        else {
            $this->grantPermissionsToAnonymousRole($permissions);
        }
    }
    
    /**
     * Performs a HTTP request. Wraps the Guzzle HTTP client.
     *
     * Why wrap the Guzzle HTTP client? Because we want to keep the actual test
     * code as simple as possible, and hence not require them to specify the
     * 'http_errors = FALSE' request option, nor do we want them to have to
     * convert Drupal Url objects to strings.
     *
     * We also don't want to follow redirects automatically, to ensure these tests
     * are able to detect when redirects are added or removed.
     *
     * @see \GuzzleHttp\ClientInterface::request()
     *
     * @param string $method
     *   HTTP method.
     * @param \Drupal\Core\Url $url
     *   URL to request.
     * @param array $request_options
     *   Request options to apply.
     *
     * @return \Psr\Http\Message\ResponseInterface
     */
    protected function request($method, Url $url, array $request_options) {
        $request_options[RequestOptions::HTTP_ERRORS] = FALSE;
        $request_options[RequestOptions::ALLOW_REDIRECTS] = FALSE;
        $request_options = $this->decorateWithXdebugCookie($request_options);
        $client = $this->getHttpClient();
        return $client->request($method, $url->setAbsolute(TRUE)
            ->toString(), $request_options);
    }
    
    /**
     * Asserts that a resource response has the given status code and body.
     *
     * @param int $expected_status_code
     *   The expected response status.
     * @param string|false $expected_body
     *   The expected response body. FALSE in case this should not be asserted.
     * @param \Psr\Http\Message\ResponseInterface $response
     *   The response to assert.
     * @param string[]|false $expected_cache_tags
     *   (optional) The expected cache tags in the X-Drupal-Cache-Tags response
     *   header, or FALSE if that header should be absent. Defaults to FALSE.
     * @param string[]|false $expected_cache_contexts
     *   (optional) The expected cache contexts in the X-Drupal-Cache-Contexts
     *   response header, or FALSE if that header should be absent. Defaults to
     *   FALSE.
     * @param string|false $expected_page_cache_header_value
     *   (optional) The expected X-Drupal-Cache response header value, or FALSE if
     *   that header should be absent. Possible strings: 'MISS', 'HIT'. Defaults
     *   to FALSE.
     * @param string|false $expected_dynamic_page_cache_header_value
     *   (optional) The expected X-Drupal-Dynamic-Cache response header value, or
     *   FALSE if that header should be absent. Possible strings: 'MISS', 'HIT'.
     *   Defaults to FALSE.
     */
    protected function assertResourceResponse($expected_status_code, $expected_body, ResponseInterface $response, $expected_cache_tags = FALSE, $expected_cache_contexts = FALSE, $expected_page_cache_header_value = FALSE, $expected_dynamic_page_cache_header_value = FALSE) {
        $this->assertSame($expected_status_code, $response->getStatusCode());
        if ($expected_status_code === 204) {
            // DELETE responses should not include a Content-Type header. But Apache
            // sets it to 'text/html' by default. We also cannot detect the presence
            // of Apache either here in the CLI. For now having this documented here
            // is all we can do.
            // $this->assertFalse($response->hasHeader('Content-Type'));
            $this->assertSame('', (string) $response->getBody());
        }
        else {
            $this->assertSame([
                static::$mimeType,
            ], $response->getHeader('Content-Type'));
            if ($expected_body !== FALSE) {
                $this->assertSame($expected_body, (string) $response->getBody());
            }
        }
        // Expected cache tags: X-Drupal-Cache-Tags header.
        $this->assertSame($expected_cache_tags !== FALSE, $response->hasHeader('X-Drupal-Cache-Tags'));
        if (is_array($expected_cache_tags)) {
            $this->assertEqualsCanonicalizing($expected_cache_tags, explode(' ', $response->getHeader('X-Drupal-Cache-Tags')[0]));
        }
        // Expected cache contexts: X-Drupal-Cache-Contexts header.
        $this->assertSame($expected_cache_contexts !== FALSE, $response->hasHeader('X-Drupal-Cache-Contexts'));
        if (is_array($expected_cache_contexts)) {
            $this->assertEqualsCanonicalizing($expected_cache_contexts, explode(' ', $response->getHeader('X-Drupal-Cache-Contexts')[0]));
        }
        // Expected Page Cache header value: X-Drupal-Cache header.
        if ($expected_page_cache_header_value !== FALSE) {
            $this->assertTrue($response->hasHeader('X-Drupal-Cache'));
            $this->assertSame($expected_page_cache_header_value, $response->getHeader('X-Drupal-Cache')[0]);
        }
        else {
            $this->assertFalse($response->hasHeader('X-Drupal-Cache'));
        }
        // Expected Dynamic Page Cache header value: X-Drupal-Dynamic-Cache header.
        if ($expected_dynamic_page_cache_header_value !== FALSE) {
            $this->assertTrue($response->hasHeader('X-Drupal-Dynamic-Cache'));
            $this->assertSame($expected_dynamic_page_cache_header_value, $response->getHeader('X-Drupal-Dynamic-Cache')[0]);
        }
        else {
            $this->assertFalse($response->hasHeader('X-Drupal-Dynamic-Cache'));
        }
    }
    
    /**
     * Asserts that a resource error response has the given message.
     *
     * @param int $expected_status_code
     *   The expected response status.
     * @param string $expected_message
     *   The expected error message.
     * @param \Psr\Http\Message\ResponseInterface $response
     *   The error response to assert.
     * @param string[]|false $expected_cache_tags
     *   (optional) The expected cache tags in the X-Drupal-Cache-Tags response
     *   header, or FALSE if that header should be absent. Defaults to FALSE.
     * @param string[]|false $expected_cache_contexts
     *   (optional) The expected cache contexts in the X-Drupal-Cache-Contexts
     *   response header, or FALSE if that header should be absent. Defaults to
     *   FALSE.
     * @param string|false $expected_page_cache_header_value
     *   (optional) The expected X-Drupal-Cache response header value, or FALSE if
     *   that header should be absent. Possible strings: 'MISS', 'HIT'. Defaults
     *   to FALSE.
     * @param string|false $expected_dynamic_page_cache_header_value
     *   (optional) The expected X-Drupal-Dynamic-Cache response header value, or
     *   FALSE if that header should be absent. Possible strings: 'MISS', 'HIT'.
     *   Defaults to FALSE.
     */
    protected function assertResourceErrorResponse($expected_status_code, $expected_message, ResponseInterface $response, $expected_cache_tags = FALSE, $expected_cache_contexts = FALSE, $expected_page_cache_header_value = FALSE, $expected_dynamic_page_cache_header_value = FALSE) {
        $expected_body = $expected_message !== FALSE ? $this->serializer
            ->encode([
            'message' => $expected_message,
        ], static::$format) : FALSE;
        $this->assertResourceResponse($expected_status_code, $expected_body, $response, $expected_cache_tags, $expected_cache_contexts, $expected_page_cache_header_value, $expected_dynamic_page_cache_header_value);
    }
    
    /**
     * Adds the Xdebug cookie to the request options.
     *
     * @param array $request_options
     *   The request options.
     *
     * @return array
     *   Request options updated with the Xdebug cookie if present.
     */
    protected function decorateWithXdebugCookie(array $request_options) {
        $session = $this->getSession();
        $driver = $session->getDriver();
        if ($driver instanceof BrowserKitDriver) {
            $client = $driver->getClient();
            foreach ($client->getCookieJar()
                ->all() as $cookie) {
                if (isset($request_options[RequestOptions::HEADERS]['Cookie'])) {
                    $request_options[RequestOptions::HEADERS]['Cookie'] .= '; ' . $cookie->getName() . '=' . $cookie->getValue();
                }
                else {
                    $request_options[RequestOptions::HEADERS]['Cookie'] = $cookie->getName() . '=' . $cookie->getValue();
                }
            }
        }
        return $request_options;
    }
    
    /**
     * Recursively sorts an array by key.
     *
     * @param array $array
     *   An array to sort.
     *
     * @return array
     *   The sorted array.
     */
    protected static function recursiveKSort(array &$array) {
        // First, sort the main array.
        ksort($array);
        // Then check for child arrays.
        foreach ($array as $key => &$value) {
            if (is_array($value)) {
                static::recursiveKSort($value);
            }
        }
        return $array;
    }

}