diff --git a/.travis.yml b/.travis.yml
index eda7549c..13962424 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,7 @@ php:
   - 5.5
   - 5.6
   - 7.0
+  - 7.1
   - hhvm
 
 install:
@@ -21,4 +22,4 @@ script:
 
 branches:
   only:
-    - master
\ No newline at end of file
+    - master
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f5b5bf68..2ae31e9d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,35 @@
 # Changelog
 
+## 5.1.3 (released 2016-10-12)
+
+* Fixed WWW-Authenticate header (Issue #669)
+* Increase the recommended RSA key length from 1024 to 2048 bits (Issue #668)
+
+## 5.1.2 (released 2016-09-19)
+
+* Fixed `finalizeScopes` call (Issue #650)
+
+## 5.1.1 (released 2016-07-26)
+
+* Improved test suite (Issue #614)
+* Updated docblocks (Issue #616)
+* Replace `array_shift` with `foreach` loop (Issue #621)
+* Allow easy addition of custom fields to Bearer token response (Issue #624)
+* Key file auto-generation from string (Issue #625)
+
+## 5.1.0 (released 2016-06-28)
+
+* Implemented RFC7636 (Issue #574)
+* Unify middleware exception responses (Issue #578)
+* Updated examples (Issue #589)
+* Ensure state is in access denied redirect (Issue #597)
+* Remove redundant `isExpired()` method from entity interfaces and traits (Issue #600)
+* Added a check for unique access token constraint violation (Issue #601)
+* Look at Authorization header directly for HTTP Basic auth checks (Issue #604)
+* Added catch Runtime exception when parsing JWT string (Issue #605)
+* Allow `paragonie/random_compat` 2.x (Issue #606)
+* Added `indigophp/hash-compat` to Composer suggestions and `require-dev` for PHP 5.5 support
+
 ## 5.0.3 (released 2016-05-04)
 
 * Fix hints in PasswordGrant (Issue #560)
diff --git a/README.md b/README.md
index 2cb8349d..8da0cf44 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@
 [![Quality Score](https://img.shields.io/scrutinizer/g/thephpleague/oauth2-server.svg?style=flat-square)](https://scrutinizer-ci.com/g/thephpleague/oauth2-server)
 [![Total Downloads](https://img.shields.io/packagist/dt/league/oauth2-server.svg?style=flat-square)](https://packagist.org/packages/league/oauth2-server)
 
-`league/oauth2-server` is a a standards compliant implementation of an [OAuth 2.0](https://tools.ietf.org/html/rfc6749) authorization server written in PHP which makes working with OAuth 2.0 trivial. You can easily configure an OAuth 2.0 server to protect your API with access tokens, or allow clients to request new access tokens and refresh them.
+`league/oauth2-server` is a standards compliant implementation of an [OAuth 2.0](https://tools.ietf.org/html/rfc6749) authorization server written in PHP which makes working with OAuth 2.0 trivial. You can easily configure an OAuth 2.0 server to protect your API with access tokens, or allow clients to request new access tokens and refresh them.
 
 It supports out of the box the following grants:
 
@@ -33,6 +33,7 @@ The following versions of PHP are supported:
 * PHP 5.5 (>=5.5.9)
 * PHP 5.6
 * PHP 7.0
+* PHP 7.1
 * HHVM
 
 The `openssl` extension is also required.
@@ -58,8 +59,7 @@ If you have any questions about OAuth _please_ open a ticket here; please **don'
 
 ## Commercial Support
 
-If you would like help implementing this library into your existing platform, or would like to 
- some advice or training for you and your team please email Alex Bilbie at `hello@glyndelabs.com`.
+If you would like help implementing this library into your existing platform, or would be interested in OAuth advice or training for you and your team please get in touch with [Glynde Labs](https://glyndelabs.com).
 
 ## Security
 
diff --git a/composer.json b/composer.json
index 5b506f12..64df3ccb 100644
--- a/composer.json
+++ b/composer.json
@@ -8,7 +8,7 @@
         "ext-openssl": "*",
         "league/event": "^2.1",
         "lcobucci/jwt": "^3.1",
-        "paragonie/random_compat": "^1.1",
+        "paragonie/random_compat": "^1.1 || ^2.0",
         "psr/http-message": "^1.0"
     },
     "require-dev": {
diff --git a/examples/README.md b/examples/README.md
index bc785ee6..d8898b46 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -3,7 +3,7 @@
 ## Installation
 
 0. Run `composer install` in this directory to install dependencies
-0. Create a private key `openssl genrsa -out private.key 1024`
+0. Create a private key `openssl genrsa -out private.key 2048`
 0. Create a public key `openssl rsa -in private.key -pubout > public.key`
 0. `cd` into the public directory
 0. Start a PHP server `php -S localhost:4444`
diff --git a/examples/public/api.php b/examples/public/api.php
index c386363c..3032ffed 100644
--- a/examples/public/api.php
+++ b/examples/public/api.php
@@ -31,7 +31,6 @@ $app->add(
 $app->get(
     '/users',
     function (ServerRequestInterface $request, ResponseInterface $response) use ($app) {
-
         $users = [
             [
                 'id'    => 123,
@@ -70,4 +69,4 @@ $app->get(
     }
 );
 
-$app->run();
\ No newline at end of file
+$app->run();
diff --git a/examples/public/client_credentials.php b/examples/public/client_credentials.php
index e4b8ddff..c982f275 100644
--- a/examples/public/client_credentials.php
+++ b/examples/public/client_credentials.php
@@ -30,9 +30,9 @@ $app = new App([
         $accessTokenRepository = new AccessTokenRepository(); // instance of AccessTokenRepositoryInterface
 
         // Path to public and private keys
-        $privateKey = 'file://'.__DIR__.'/../private.key';
+        $privateKey = 'file://' . __DIR__ . '/../private.key';
         //$privateKey = new CryptKey('file://path/to/private.key', 'passphrase'); // if private key has a pass phrase
-        $publicKey = 'file://'.__DIR__.'/../public.key';
+        $publicKey = 'file://' . __DIR__ . '/../public.key';
 
         // Setup the authorization server
         $server = new AuthorizationServer(
diff --git a/examples/public/middleware_use.php b/examples/public/middleware_use.php
index 2dfe1834..21f6bc23 100644
--- a/examples/public/middleware_use.php
+++ b/examples/public/middleware_use.php
@@ -8,6 +8,7 @@
  */
 
 use League\OAuth2\Server\AuthorizationServer;
+use League\OAuth2\Server\ResourceServer;
 use League\OAuth2\Server\Grant\AuthCodeGrant;
 use League\OAuth2\Server\Grant\RefreshTokenGrant;
 use League\OAuth2\Server\Middleware\AuthorizationServerMiddleware;
@@ -61,11 +62,20 @@ $app = new App([
         // Enable the refresh token grant on the server with a token TTL of 1 month
         $server->enableGrantType(
             new RefreshTokenGrant($refreshTokenRepository),
-            new \DateInterval('PT1M')
+            new \DateInterval('P1M')
         );
 
         return $server;
     },
+    ResourceServer::class => function () {
+        $publicKeyPath = 'file://' . __DIR__ . '/../public.key';
+
+        $server = new ResourceServer(
+            new AccessTokenRepository(),
+            $publicKeyPath
+        );
+        return $server;
+    },
 ]);
 
 // Access token issuer
@@ -94,6 +104,6 @@ $app->group('/api', function () {
 
         return $response->withBody($body);
     });
-})->add(new ResourceServerMiddleware($app->getContainer()->get(AuthorizationServer::class)));
+})->add(new ResourceServerMiddleware($app->getContainer()->get(ResourceServer::class)));
 
 $app->run();
diff --git a/examples/public/password.php b/examples/public/password.php
index 75766477..02a85a56 100644
--- a/examples/public/password.php
+++ b/examples/public/password.php
@@ -23,8 +23,8 @@ $app = new App([
             new ClientRepository(),                 // instance of ClientRepositoryInterface
             new AccessTokenRepository(),            // instance of AccessTokenRepositoryInterface
             new ScopeRepository(),                  // instance of ScopeRepositoryInterface
-            'file://'.__DIR__.'/../private.key',    // path to private key
-            'file://'.__DIR__.'/../public.key'      // path to public key
+            'file://' . __DIR__ . '/../private.key',    // path to private key
+            'file://' . __DIR__ . '/../public.key'      // path to public key
         );
 
         $grant = new PasswordGrant(
@@ -54,19 +54,17 @@ $app->post(
 
             // Try to respond to the access token request
             return $server->respondToAccessTokenRequest($request, $response);
-
         } catch (OAuthServerException $exception) {
 
             // All instances of OAuthServerException can be converted to a PSR-7 response
             return $exception->generateHttpResponse($response);
-
         } catch (\Exception $exception) {
 
             // Catch unexpected exceptions
             $body = $response->getBody();
             $body->write($exception->getMessage());
-            return $response->withStatus(500)->withBody($body);
 
+            return $response->withStatus(500)->withBody($body);
         }
     }
 );
diff --git a/examples/src/Repositories/ScopeRepository.php b/examples/src/Repositories/ScopeRepository.php
index fbd64b3e..d050d55f 100644
--- a/examples/src/Repositories/ScopeRepository.php
+++ b/examples/src/Repositories/ScopeRepository.php
@@ -48,6 +48,13 @@ class ScopeRepository implements ScopeRepositoryInterface
         ClientEntityInterface $clientEntity,
         $userIdentifier = null
     ) {
+        // Example of programatically modifying the final scope of the access token
+        if ((int) $userIdentifier === 1) {
+            $scope = new ScopeEntity();
+            $scope->setIdentifier('email');
+            $scopes[] = $scope;
+        }
+
         return $scopes;
     }
 }
diff --git a/examples/src/Repositories/UserRepository.php b/examples/src/Repositories/UserRepository.php
index 86f99970..88836cd6 100644
--- a/examples/src/Repositories/UserRepository.php
+++ b/examples/src/Repositories/UserRepository.php
@@ -11,7 +11,6 @@ namespace OAuth2ServerExamples\Repositories;
 
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Repositories\UserRepositoryInterface;
-use OAuth2ServerExamples\Entities\ScopeEntity;
 use OAuth2ServerExamples\Entities\UserEntity;
 
 class UserRepository implements UserRepositoryInterface
@@ -26,10 +25,6 @@ class UserRepository implements UserRepositoryInterface
         ClientEntityInterface $clientEntity
     ) {
         if ($username === 'alex' && $password === 'whisky') {
-            $scope = new ScopeEntity();
-            $scope->setIdentifier('email');
-            $scopes[] = $scope;
-
             return new UserEntity();
         }
 
diff --git a/src/AuthorizationServer.php b/src/AuthorizationServer.php
index 6b7a972b..0517124a 100644
--- a/src/AuthorizationServer.php
+++ b/src/AuthorizationServer.php
@@ -9,7 +9,6 @@
 
 namespace League\OAuth2\Server;
 
-use DateInterval;
 use League\Event\EmitterAwareInterface;
 use League\Event\EmitterAwareTrait;
 use League\OAuth2\Server\Exception\OAuthServerException;
@@ -28,7 +27,7 @@ class AuthorizationServer implements EmitterAwareInterface
     use EmitterAwareTrait;
 
     /**
-     * @var \League\OAuth2\Server\Grant\GrantTypeInterface[]
+     * @var GrantTypeInterface[]
      */
     protected $enabledGrantTypes = [];
 
@@ -38,44 +37,44 @@ class AuthorizationServer implements EmitterAwareInterface
     protected $grantTypeAccessTokenTTL = [];
 
     /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
      */
     protected $privateKey;
 
     /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
      */
     protected $publicKey;
 
     /**
-     * @var ResponseTypeInterface
+     * @var null|ResponseTypeInterface
      */
     protected $responseType;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\ClientRepositoryInterface
+     * @var ClientRepositoryInterface
      */
     private $clientRepository;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
      */
     private $accessTokenRepository;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\ScopeRepositoryInterface
+     * @var ScopeRepositoryInterface
      */
     private $scopeRepository;
 
     /**
      * New server instance.
      *
-     * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface      $clientRepository
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
-     * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface       $scopeRepository
-     * @param \League\OAuth2\Server\CryptKey|string                             $privateKey
-     * @param \League\OAuth2\Server\CryptKey|string                             $publicKey
-     * @param null|\League\OAuth2\Server\ResponseTypes\ResponseTypeInterface    $responseType
+     * @param ClientRepositoryInterface      $clientRepository
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
+     * @param ScopeRepositoryInterface       $scopeRepository
+     * @param CryptKey|string                $privateKey
+     * @param CryptKey|string                $publicKey
+     * @param null|ResponseTypeInterface     $responseType
      */
     public function __construct(
         ClientRepositoryInterface $clientRepository,
@@ -89,12 +88,12 @@ class AuthorizationServer implements EmitterAwareInterface
         $this->accessTokenRepository = $accessTokenRepository;
         $this->scopeRepository = $scopeRepository;
 
-        if (!$privateKey instanceof CryptKey) {
+        if ($privateKey instanceof CryptKey === false) {
             $privateKey = new CryptKey($privateKey);
         }
         $this->privateKey = $privateKey;
 
-        if (!$publicKey instanceof CryptKey) {
+        if ($publicKey instanceof CryptKey === false) {
             $publicKey = new CryptKey($publicKey);
         }
         $this->publicKey = $publicKey;
@@ -105,12 +104,12 @@ class AuthorizationServer implements EmitterAwareInterface
     /**
      * Enable a grant type on the server.
      *
-     * @param \League\OAuth2\Server\Grant\GrantTypeInterface $grantType
-     * @param \DateInterval                                  $accessTokenTTL
+     * @param GrantTypeInterface $grantType
+     * @param null|\DateInterval $accessTokenTTL
      */
-    public function enableGrantType(GrantTypeInterface $grantType, DateInterval $accessTokenTTL = null)
+    public function enableGrantType(GrantTypeInterface $grantType, \DateInterval $accessTokenTTL = null)
     {
-        if ($accessTokenTTL instanceof DateInterval === false) {
+        if ($accessTokenTTL instanceof \DateInterval === false) {
             $accessTokenTTL = new \DateInterval('PT1H');
         }
 
@@ -128,22 +127,17 @@ class AuthorizationServer implements EmitterAwareInterface
     /**
      * Validate an authorization request
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \League\OAuth2\Server\RequestTypes\AuthorizationRequest|null
+     * @return AuthorizationRequest
      */
     public function validateAuthorizationRequest(ServerRequestInterface $request)
     {
-        $authRequest = null;
-        $enabledGrantTypes = $this->enabledGrantTypes;
-        while ($authRequest === null && $grantType = array_shift($enabledGrantTypes)) {
-            /** @var \League\OAuth2\Server\Grant\GrantTypeInterface $grantType */
+        foreach ($this->enabledGrantTypes as $grantType) {
             if ($grantType->canRespondToAuthorizationRequest($request)) {
-                $authRequest = $grantType->validateAuthorizationRequest($request);
-
-                return $authRequest;
+                return $grantType->validateAuthorizationRequest($request);
             }
         }
 
@@ -153,10 +147,10 @@ class AuthorizationServer implements EmitterAwareInterface
     /**
      * Complete an authorization request
      *
-     * @param \League\OAuth2\Server\RequestTypes\AuthorizationRequest $authRequest
-     * @param \Psr\Http\Message\ResponseInterface                     $response
+     * @param AuthorizationRequest $authRequest
+     * @param ResponseInterface    $response
      *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
      */
     public function completeAuthorizationRequest(AuthorizationRequest $authRequest, ResponseInterface $response)
     {
@@ -168,29 +162,27 @@ class AuthorizationServer implements EmitterAwareInterface
     /**
      * Return an access token response.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
      */
     public function respondToAccessTokenRequest(ServerRequestInterface $request, ResponseInterface $response)
     {
-        $tokenResponse = null;
-        while ($tokenResponse === null && $grantType = array_shift($this->enabledGrantTypes)) {
-            /** @var \League\OAuth2\Server\Grant\GrantTypeInterface $grantType */
+        foreach ($this->enabledGrantTypes as $grantType) {
             if ($grantType->canRespondToAccessTokenRequest($request)) {
                 $tokenResponse = $grantType->respondToAccessTokenRequest(
                     $request,
                     $this->getResponseType(),
                     $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()]
                 );
-            }
-        }
 
-        if ($tokenResponse instanceof ResponseTypeInterface) {
-            return $tokenResponse->generateHttpResponse($response);
+                if ($tokenResponse instanceof ResponseTypeInterface) {
+                    return $tokenResponse->generateHttpResponse($response);
+                }
+            }
         }
 
         throw OAuthServerException::unsupportedGrantType();
@@ -203,7 +195,7 @@ class AuthorizationServer implements EmitterAwareInterface
      */
     protected function getResponseType()
     {
-        if (!$this->responseType instanceof ResponseTypeInterface) {
+        if ($this->responseType instanceof ResponseTypeInterface === false) {
             $this->responseType = new BearerTokenResponse();
         }
 
diff --git a/src/AuthorizationValidators/BearerTokenValidator.php b/src/AuthorizationValidators/BearerTokenValidator.php
index 88034750..2bab4cb5 100644
--- a/src/AuthorizationValidators/BearerTokenValidator.php
+++ b/src/AuthorizationValidators/BearerTokenValidator.php
@@ -22,14 +22,12 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
     use CryptTrait;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
      */
     private $accessTokenRepository;
 
     /**
-     * BearerTokenValidator constructor.
-     *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
      */
     public function __construct(AccessTokenRepositoryInterface $accessTokenRepository)
     {
@@ -77,6 +75,9 @@ class BearerTokenValidator implements AuthorizationValidatorInterface
         } catch (\InvalidArgumentException $exception) {
             // JWT couldn't be parsed so return the request as is
             throw OAuthServerException::accessDenied($exception->getMessage());
+        } catch (\RuntimeException $exception) {
+            //JWR couldn't be parsed so return the request as is
+            throw OAuthServerException::accessDenied('Error while decoding to JSON');
         }
     }
 }
diff --git a/src/CryptKey.php b/src/CryptKey.php
index 4ea05264..aedeafb0 100644
--- a/src/CryptKey.php
+++ b/src/CryptKey.php
@@ -8,17 +8,21 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server;
 
 class CryptKey
 {
+    const RSA_KEY_PATTERN =
+        '/^(-----BEGIN (RSA )?(PUBLIC|PRIVATE) KEY-----\n)(.|\n)+(-----END (RSA )?(PUBLIC|PRIVATE) KEY-----)$/';
+
     /**
      * @var string
      */
     protected $keyPath;
 
     /**
-     * @var string
+     * @var null|string
      */
     protected $passPhrase;
 
@@ -28,6 +32,10 @@ class CryptKey
      */
     public function __construct($keyPath, $passPhrase = null)
     {
+        if (preg_match(self::RSA_KEY_PATTERN, $keyPath)) {
+            $keyPath = $this->saveKeyToFile($keyPath);
+        }
+
         if (strpos($keyPath, 'file://') !== 0) {
             $keyPath = 'file://' . $keyPath;
         }
@@ -40,6 +48,28 @@ class CryptKey
         $this->passPhrase = $passPhrase;
     }
 
+    /**
+     * @param string $key
+     *
+     * @throws \RuntimeException
+     *
+     * @return string
+     */
+    private function saveKeyToFile($key)
+    {
+        $keyPath = sys_get_temp_dir() . '/' . sha1($key) . '.key';
+
+        if (!file_exists($keyPath) && !touch($keyPath)) {
+            // @codeCoverageIgnoreStart
+            throw new \RuntimeException('"%s" key file could not be created', $keyPath);
+            // @codeCoverageIgnoreEnd
+        }
+
+        file_put_contents($keyPath, $key);
+
+        return 'file://' . $keyPath;
+    }
+
     /**
      * Retrieve key path.
      *
diff --git a/src/CryptTrait.php b/src/CryptTrait.php
index 1075ea12..d417e115 100644
--- a/src/CryptTrait.php
+++ b/src/CryptTrait.php
@@ -8,24 +8,25 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server;
 
 trait CryptTrait
 {
     /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
      */
     protected $privateKey;
 
     /**
-     * @var \League\OAuth2\Server\CryptKey
+     * @var CryptKey
      */
     protected $publicKey;
 
     /**
      * Set path to private key.
      *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
      */
     public function setPrivateKey(CryptKey $privateKey)
     {
@@ -35,7 +36,7 @@ trait CryptTrait
     /**
      * Set path to public key.
      *
-     * @param \League\OAuth2\Server\CryptKey $publicKey
+     * @param CryptKey $publicKey
      */
     public function setPublicKey(CryptKey $publicKey)
     {
@@ -47,6 +48,8 @@ trait CryptTrait
      *
      * @param string $unencryptedData
      *
+     * @throws \LogicException
+     *
      * @return string
      */
     protected function encrypt($unencryptedData)
diff --git a/src/Entities/AccessTokenEntityInterface.php b/src/Entities/AccessTokenEntityInterface.php
index 642cc99f..c297e267 100644
--- a/src/Entities/AccessTokenEntityInterface.php
+++ b/src/Entities/AccessTokenEntityInterface.php
@@ -16,7 +16,7 @@ interface AccessTokenEntityInterface extends TokenInterface
     /**
      * Generate a JWT from the access token
      *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
      *
      * @return string
      */
diff --git a/src/Entities/RefreshTokenEntityInterface.php b/src/Entities/RefreshTokenEntityInterface.php
index 8b7d587d..05e86e00 100644
--- a/src/Entities/RefreshTokenEntityInterface.php
+++ b/src/Entities/RefreshTokenEntityInterface.php
@@ -42,21 +42,14 @@ interface RefreshTokenEntityInterface
     /**
      * Set the access token that the refresh token was associated with.
      *
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
      */
     public function setAccessToken(AccessTokenEntityInterface $accessToken);
 
     /**
      * Get the access token that the refresh token was originally associated with.
      *
-     * @return \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @return AccessTokenEntityInterface
      */
     public function getAccessToken();
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired();
 }
diff --git a/src/Entities/TokenInterface.php b/src/Entities/TokenInterface.php
index 7d7c6d33..c842b09a 100644
--- a/src/Entities/TokenInterface.php
+++ b/src/Entities/TokenInterface.php
@@ -63,14 +63,14 @@ interface TokenInterface
     /**
      * Set the client that the token was issued to.
      *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ClientEntityInterface $client
      */
     public function setClient(ClientEntityInterface $client);
 
     /**
      * Associate a scope with the token.
      *
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface $scope
+     * @param ScopeEntityInterface $scope
      */
     public function addScope(ScopeEntityInterface $scope);
 
@@ -80,11 +80,4 @@ interface TokenInterface
      * @return ScopeEntityInterface[]
      */
     public function getScopes();
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired();
 }
diff --git a/src/Entities/Traits/AccessTokenTrait.php b/src/Entities/Traits/AccessTokenTrait.php
index 31a8eb48..741d6c19 100644
--- a/src/Entities/Traits/AccessTokenTrait.php
+++ b/src/Entities/Traits/AccessTokenTrait.php
@@ -21,7 +21,7 @@ trait AccessTokenTrait
     /**
      * Generate a JWT from the access token
      *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
      *
      * @return string
      */
diff --git a/src/Entities/Traits/ClientTrait.php b/src/Entities/Traits/ClientTrait.php
index 8e44ce09..fec76a6f 100644
--- a/src/Entities/Traits/ClientTrait.php
+++ b/src/Entities/Traits/ClientTrait.php
@@ -11,8 +11,14 @@ namespace League\OAuth2\Server\Entities\Traits;
 
 trait ClientTrait
 {
+    /**
+     * @var string
+     */
     protected $name;
 
+    /**
+     * @var string|string[]
+     */
     protected $redirectUri;
 
     /**
diff --git a/src/Entities/Traits/RefreshTokenTrait.php b/src/Entities/Traits/RefreshTokenTrait.php
index 28d31a02..fb9dbc68 100644
--- a/src/Entities/Traits/RefreshTokenTrait.php
+++ b/src/Entities/Traits/RefreshTokenTrait.php
@@ -9,7 +9,6 @@
 
 namespace League\OAuth2\Server\Entities\Traits;
 
-use DateTime;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 
 trait RefreshTokenTrait
@@ -20,7 +19,7 @@ trait RefreshTokenTrait
     protected $accessToken;
 
     /**
-     * @var DateTime
+     * @var \DateTime
      */
     protected $expiryDateTime;
 
@@ -43,7 +42,7 @@ trait RefreshTokenTrait
     /**
      * Get the token's expiry date time.
      *
-     * @return DateTime
+     * @return \DateTime
      */
     public function getExpiryDateTime()
     {
@@ -53,20 +52,10 @@ trait RefreshTokenTrait
     /**
      * Set the date time when the token expires.
      *
-     * @param DateTime $dateTime
+     * @param \DateTime $dateTime
      */
-    public function setExpiryDateTime(DateTime $dateTime)
+    public function setExpiryDateTime(\DateTime $dateTime)
     {
         $this->expiryDateTime = $dateTime;
     }
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired()
-    {
-        return (new DateTime()) > $this->getExpiryDateTime();
-    }
 }
diff --git a/src/Entities/Traits/TokenEntityTrait.php b/src/Entities/Traits/TokenEntityTrait.php
index 87fdd2f4..0b5608cd 100644
--- a/src/Entities/Traits/TokenEntityTrait.php
+++ b/src/Entities/Traits/TokenEntityTrait.php
@@ -9,7 +9,6 @@
 
 namespace League\OAuth2\Server\Entities\Traits;
 
-use DateTime;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
 
@@ -21,7 +20,7 @@ trait TokenEntityTrait
     protected $scopes = [];
 
     /**
-     * @var DateTime
+     * @var \DateTime
      */
     protected $expiryDateTime;
 
@@ -38,7 +37,7 @@ trait TokenEntityTrait
     /**
      * Associate a scope with the token.
      *
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface $scope
+     * @param ScopeEntityInterface $scope
      */
     public function addScope(ScopeEntityInterface $scope)
     {
@@ -58,7 +57,7 @@ trait TokenEntityTrait
     /**
      * Get the token's expiry date time.
      *
-     * @return DateTime
+     * @return \DateTime
      */
     public function getExpiryDateTime()
     {
@@ -68,9 +67,9 @@ trait TokenEntityTrait
     /**
      * Set the date time when the token expires.
      *
-     * @param DateTime $dateTime
+     * @param \DateTime $dateTime
      */
-    public function setExpiryDateTime(DateTime $dateTime)
+    public function setExpiryDateTime(\DateTime $dateTime)
     {
         $this->expiryDateTime = $dateTime;
     }
@@ -108,20 +107,10 @@ trait TokenEntityTrait
     /**
      * Set the client that the token was issued to.
      *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ClientEntityInterface $client
      */
     public function setClient(ClientEntityInterface $client)
     {
         $this->client = $client;
     }
-
-    /**
-     * Has the token expired?
-     *
-     * @return bool
-     */
-    public function isExpired()
-    {
-        return (new DateTime()) > $this->getExpiryDateTime();
-    }
 }
diff --git a/src/Exception/OAuthServerException.php b/src/Exception/OAuthServerException.php
index 4a6e1832..6ffa0fb1 100644
--- a/src/Exception/OAuthServerException.php
+++ b/src/Exception/OAuthServerException.php
@@ -69,7 +69,7 @@ class OAuthServerException extends \Exception
      * Invalid request error.
      *
      * @param string      $parameter The invalid parameter
-     * @param string|null $hint
+     * @param null|string $hint
      *
      * @return static
      */
@@ -143,7 +143,7 @@ class OAuthServerException extends \Exception
     /**
      * Invalid refresh token.
      *
-     * @param string|null $hint
+     * @param null|string $hint
      *
      * @return static
      */
@@ -155,8 +155,8 @@ class OAuthServerException extends \Exception
     /**
      * Access denied.
      *
-     * @param string|null $hint
-     * @param string|null $redirectUri
+     * @param null|string $hint
+     * @param null|string $redirectUri
      *
      * @return static
      */
@@ -203,11 +203,10 @@ class OAuthServerException extends \Exception
     /**
      * Generate a HTTP response.
      *
-     * @param \Psr\Http\Message\ResponseInterface $response
-     * @param bool                                $useFragment True if errors should be in the URI fragment instead of
-     *                                                         query string
+     * @param ResponseInterface $response
+     * @param bool              $useFragment True if errors should be in the URI fragment instead of query string
      *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
      */
     public function generateHttpResponse(ResponseInterface $response, $useFragment = false)
     {
@@ -268,7 +267,7 @@ class OAuthServerException extends \Exception
             ) {
                 $authScheme = 'Bearer';
             }
-            $headers[] = 'WWW-Authenticate: ' . $authScheme . ' realm="OAuth"';
+            $headers['WWW-Authenticate'] = $authScheme . ' realm="OAuth"';
         }
         // @codeCoverageIgnoreEnd
         return $headers;
diff --git a/src/Exception/UniqueTokenIdentifierConstraintViolationException.php b/src/Exception/UniqueTokenIdentifierConstraintViolationException.php
new file mode 100644
index 00000000..a67855b2
--- /dev/null
+++ b/src/Exception/UniqueTokenIdentifierConstraintViolationException.php
@@ -0,0 +1,20 @@
+<?php
+/**
+ * @author      Ivan Kurnosov <zerkms@zerkms.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */
+
+namespace League\OAuth2\Server\Exception;
+
+class UniqueTokenIdentifierConstraintViolationException extends OAuthServerException
+{
+    public static function create()
+    {
+        $errorMessage = 'Could not create unique access token identifier';
+
+        return new static($errorMessage, 100, 'access_token_duplicate', 500);
+    }
+}
diff --git a/src/Grant/AbstractGrant.php b/src/Grant/AbstractGrant.php
index 9c72a9a1..d916e3f1 100644
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -13,9 +13,12 @@ namespace League\OAuth2\Server\Grant;
 use League\Event\EmitterAwareTrait;
 use League\OAuth2\Server\CryptTrait;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
+use League\OAuth2\Server\Entities\AuthCodeEntityInterface;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
@@ -35,6 +38,8 @@ abstract class AbstractGrant implements GrantTypeInterface
 
     const SCOPE_DELIMITER_STRING = ' ';
 
+    const MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS = 10;
+
     /**
      * @var ClientRepositoryInterface
      */
@@ -51,17 +56,17 @@ abstract class AbstractGrant implements GrantTypeInterface
     protected $scopeRepository;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface
+     * @var AuthCodeRepositoryInterface
      */
     protected $authCodeRepository;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface
+     * @var RefreshTokenRepositoryInterface
      */
     protected $refreshTokenRepository;
 
     /**
-     * @var \League\OAuth2\Server\Repositories\UserRepositoryInterface
+     * @var UserRepositoryInterface
      */
     protected $userRepository;
 
@@ -95,7 +100,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     }
 
     /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
      */
     public function setRefreshTokenRepository(RefreshTokenRepositoryInterface $refreshTokenRepository)
     {
@@ -103,7 +108,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     }
 
     /**
-     * @param \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface $authCodeRepository
+     * @param AuthCodeRepositoryInterface $authCodeRepository
      */
     public function setAuthCodeRepository(AuthCodeRepositoryInterface $authCodeRepository)
     {
@@ -111,7 +116,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     }
 
     /**
-     * @param \League\OAuth2\Server\Repositories\UserRepositoryInterface $userRepository
+     * @param UserRepositoryInterface $userRepository
      */
     public function setUserRepository(UserRepositoryInterface $userRepository)
     {
@@ -129,29 +134,23 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * Validate the client.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \League\OAuth2\Server\Entities\ClientEntityInterface
+     * @return ClientEntityInterface
      */
     protected function validateClient(ServerRequestInterface $request)
     {
-        $clientId = $this->getRequestParameter(
-            'client_id',
-            $request,
-            $this->getServerParameter('PHP_AUTH_USER', $request)
-        );
+        list($basicAuthUser, $basicAuthPassword) = $this->getBasicAuthCredentials($request);
+
+        $clientId = $this->getRequestParameter('client_id', $request, $basicAuthUser);
         if (is_null($clientId)) {
             throw OAuthServerException::invalidRequest('client_id');
         }
 
         // If the client is confidential require the client secret
-        $clientSecret = $this->getRequestParameter(
-            'client_secret',
-            $request,
-            $this->getServerParameter('PHP_AUTH_PW', $request)
-        );
+        $clientSecret = $this->getRequestParameter('client_secret', $request, $basicAuthPassword);
 
         $client = $this->clientRepository->getClientEntity(
             $clientId,
@@ -160,7 +159,7 @@ abstract class AbstractGrant implements GrantTypeInterface
             true
         );
 
-        if (!$client instanceof ClientEntityInterface) {
+        if ($client instanceof ClientEntityInterface === false) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
             throw OAuthServerException::invalidClient();
         }
@@ -192,9 +191,9 @@ abstract class AbstractGrant implements GrantTypeInterface
      * @param string $scopes
      * @param string $redirectUri
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
      */
     public function validateScopes(
         $scopes,
@@ -211,7 +210,7 @@ abstract class AbstractGrant implements GrantTypeInterface
         foreach ($scopesList as $scopeItem) {
             $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeItem);
 
-            if (!$scope instanceof ScopeEntityInterface) {
+            if ($scope instanceof ScopeEntityInterface === false) {
                 throw OAuthServerException::invalidScope($scopeItem, $redirectUri);
             }
 
@@ -224,9 +223,9 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * Retrieve request parameter.
      *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
      *
      * @return null|string
      */
@@ -237,12 +236,45 @@ abstract class AbstractGrant implements GrantTypeInterface
         return isset($requestParameters[$parameter]) ? $requestParameters[$parameter] : $default;
     }
 
+    /**
+     * Retrieve HTTP Basic Auth credentials with the Authorization header
+     * of a request. First index of the returned array is the username,
+     * second is the password (so list() will work). If the header does
+     * not exist, or is otherwise an invalid HTTP Basic header, return
+     * [null, null].
+     *
+     * @param ServerRequestInterface $request
+     *
+     * @return string[]|null[]
+     */
+    protected function getBasicAuthCredentials(ServerRequestInterface $request)
+    {
+        if (!$request->hasHeader('Authorization')) {
+            return [null, null];
+        }
+
+        $header = $request->getHeader('Authorization')[0];
+        if (strpos($header, 'Basic ') !== 0) {
+            return [null, null];
+        }
+
+        if (!($decoded = base64_decode(substr($header, 6)))) {
+            return [null, null];
+        }
+
+        if (strpos($decoded, ':') === false) {
+            return [null, null]; // HTTP Basic header without colon isn't valid
+        }
+
+        return explode(':', $decoded, 2);
+    }
+
     /**
      * Retrieve query string parameter.
      *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
      *
      * @return null|string
      */
@@ -254,9 +286,9 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * Retrieve cookie parameter.
      *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
      *
      * @return null|string
      */
@@ -268,9 +300,9 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * Retrieve server parameter.
      *
-     * @param string                                   $parameter
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param mixed                                    $default
+     * @param string                 $parameter
+     * @param ServerRequestInterface $request
+     * @param mixed                  $default
      *
      * @return null|string
      */
@@ -282,12 +314,15 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * Issue an access token.
      *
-     * @param \DateInterval                                         $accessTokenTTL
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $client
-     * @param string                                                $userIdentifier
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param \DateInterval          $accessTokenTTL
+     * @param ClientEntityInterface  $client
+     * @param string                 $userIdentifier
+     * @param ScopeEntityInterface[] $scopes
      *
-     * @return \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return AccessTokenEntityInterface
      */
     protected function issueAccessToken(
         \DateInterval $accessTokenTTL,
@@ -295,31 +330,44 @@ abstract class AbstractGrant implements GrantTypeInterface
         $userIdentifier,
         array $scopes = []
     ) {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
         $accessToken = $this->accessTokenRepository->getNewToken($client, $scopes, $userIdentifier);
         $accessToken->setClient($client);
         $accessToken->setUserIdentifier($userIdentifier);
-        $accessToken->setIdentifier($this->generateUniqueIdentifier());
         $accessToken->setExpiryDateTime((new \DateTime())->add($accessTokenTTL));
 
         foreach ($scopes as $scope) {
             $accessToken->addScope($scope);
         }
 
-        $this->accessTokenRepository->persistNewAccessToken($accessToken);
+        while ($maxGenerationAttempts-- > 0) {
+            $accessToken->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->accessTokenRepository->persistNewAccessToken($accessToken);
 
-        return $accessToken;
+                return $accessToken;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
     }
 
     /**
      * Issue an auth code.
      *
-     * @param \DateInterval                                         $authCodeTTL
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $client
-     * @param string                                                $userIdentifier
-     * @param string                                                $redirectUri
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param \DateInterval          $authCodeTTL
+     * @param ClientEntityInterface  $client
+     * @param string                 $userIdentifier
+     * @param string                 $redirectUri
+     * @param ScopeEntityInterface[] $scopes
      *
-     * @return \League\OAuth2\Server\Entities\AuthCodeEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return AuthCodeEntityInterface
      */
     protected function issueAuthCode(
         \DateInterval $authCodeTTL,
@@ -328,8 +376,9 @@ abstract class AbstractGrant implements GrantTypeInterface
         $redirectUri,
         array $scopes = []
     ) {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
         $authCode = $this->authCodeRepository->getNewAuthCode();
-        $authCode->setIdentifier($this->generateUniqueIdentifier());
         $authCode->setExpiryDateTime((new \DateTime())->add($authCodeTTL));
         $authCode->setClient($client);
         $authCode->setUserIdentifier($userIdentifier);
@@ -339,26 +388,48 @@ abstract class AbstractGrant implements GrantTypeInterface
             $authCode->addScope($scope);
         }
 
-        $this->authCodeRepository->persistNewAuthCode($authCode);
+        while ($maxGenerationAttempts-- > 0) {
+            $authCode->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->authCodeRepository->persistNewAuthCode($authCode);
 
-        return $authCode;
+                return $authCode;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
     }
 
     /**
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
      *
-     * @return \League\OAuth2\Server\Entities\RefreshTokenEntityInterface
+     * @throws OAuthServerException
+     * @throws UniqueTokenIdentifierConstraintViolationException
+     *
+     * @return RefreshTokenEntityInterface
      */
     protected function issueRefreshToken(AccessTokenEntityInterface $accessToken)
     {
+        $maxGenerationAttempts = self::MAX_RANDOM_TOKEN_GENERATION_ATTEMPTS;
+
         $refreshToken = $this->refreshTokenRepository->getNewRefreshToken();
-        $refreshToken->setIdentifier($this->generateUniqueIdentifier());
         $refreshToken->setExpiryDateTime((new \DateTime())->add($this->refreshTokenTTL));
         $refreshToken->setAccessToken($accessToken);
 
-        $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);
+        while ($maxGenerationAttempts-- > 0) {
+            $refreshToken->setIdentifier($this->generateUniqueIdentifier());
+            try {
+                $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);
 
-        return $refreshToken;
+                return $refreshToken;
+            } catch (UniqueTokenIdentifierConstraintViolationException $e) {
+                if ($maxGenerationAttempts === 0) {
+                    throw $e;
+                }
+            }
+        }
     }
 
     /**
@@ -366,7 +437,7 @@ abstract class AbstractGrant implements GrantTypeInterface
      *
      * @param int $length
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
      * @return string
      */
diff --git a/src/Grant/AuthCodeGrant.php b/src/Grant/AuthCodeGrant.php
index 5f736709..df89400e 100644
--- a/src/Grant/AuthCodeGrant.php
+++ b/src/Grant/AuthCodeGrant.php
@@ -9,7 +9,6 @@
 
 namespace League\OAuth2\Server\Grant;
 
-use DateInterval;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
 use League\OAuth2\Server\Entities\UserEntityInterface;
@@ -35,9 +34,9 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
     private $enableCodeExchangeProof = false;
 
     /**
-     * @param \League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface     $authCodeRepository
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
-     * @param \DateInterval                                                      $authCodeTTL
+     * @param AuthCodeRepositoryInterface     $authCodeRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param \DateInterval                   $authCodeTTL
      */
     public function __construct(
         AuthCodeRepositoryInterface $authCodeRepository,
@@ -58,18 +57,18 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
     /**
      * Respond to an access token request.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
      */
     public function respondToAccessTokenRequest(
         ServerRequestInterface $request,
         ResponseTypeInterface $responseType,
-        DateInterval $accessTokenTTL
+        \DateInterval $accessTokenTTL
     ) {
         // Validate request
         $client = $this->validateClient($request);
@@ -108,7 +107,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
             foreach ($authCodePayload->scopes as $scopeId) {
                 $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeId);
 
-                if (!$scope instanceof ScopeEntityInterface) {
+                if ($scope instanceof ScopeEntityInterface === false) {
                     // @codeCoverageIgnoreStart
                     throw OAuthServerException::invalidScope($scopeId);
                     // @codeCoverageIgnoreEnd
@@ -335,7 +334,12 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
         // The user denied the client, redirect them back with an error
         throw OAuthServerException::accessDenied(
             'The user denied the request',
-            $finalRedirectUri
+            $this->makeRedirectUri(
+                $finalRedirectUri,
+                [
+                    'state' => $authorizationRequest->getState(),
+                ]
+            )
         );
     }
 }
diff --git a/src/Grant/ClientCredentialsGrant.php b/src/Grant/ClientCredentialsGrant.php
index c8ff2d52..b5b968d4 100644
--- a/src/Grant/ClientCredentialsGrant.php
+++ b/src/Grant/ClientCredentialsGrant.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Grant;
 
 use League\OAuth2\Server\ResponseTypes\ResponseTypeInterface;
diff --git a/src/Grant/GrantTypeInterface.php b/src/Grant/GrantTypeInterface.php
index c0ffdd9c..c01a571d 100644
--- a/src/Grant/GrantTypeInterface.php
+++ b/src/Grant/GrantTypeInterface.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Grant;
 
 use League\Event\EmitterAwareInterface;
@@ -41,11 +42,11 @@ interface GrantTypeInterface extends EmitterAwareInterface
     /**
      * Respond to an incoming request.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
      *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
      */
     public function respondToAccessTokenRequest(
         ServerRequestInterface $request,
@@ -56,7 +57,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
     /**
      * The grant type should return true if it is able to response to an authorization request
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
      * @return bool
      */
@@ -69,7 +70,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
      * If the validation is successful an AuthorizationRequest object will be returned. This object can be safely
      * serialized in a user's session, and can be used during user authentication and authorization.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
      * @return AuthorizationRequest
      */
@@ -80,9 +81,9 @@ interface GrantTypeInterface extends EmitterAwareInterface
      * The AuthorizationRequest object's $userId property must be set to the authenticated user and the
      * $authorizationApproved property must reflect their desire to authorize or deny the client.
      *
-     * @param \League\OAuth2\Server\RequestTypes\AuthorizationRequest $authorizationRequest
+     * @param AuthorizationRequest $authorizationRequest
      *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
      */
     public function completeAuthorizationRequest(AuthorizationRequest $authorizationRequest);
 
@@ -91,7 +92,7 @@ interface GrantTypeInterface extends EmitterAwareInterface
      *
      * For example most grant types will check that the $_POST['grant_type'] property matches it's identifier property.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
      * @return bool
      */
@@ -100,35 +101,35 @@ interface GrantTypeInterface extends EmitterAwareInterface
     /**
      * Set the client repository.
      *
-     * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface $clientRepository
+     * @param ClientRepositoryInterface $clientRepository
      */
     public function setClientRepository(ClientRepositoryInterface $clientRepository);
 
     /**
      * Set the access token repository.
      *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
+     * @param AccessTokenRepositoryInterface $accessTokenRepository
      */
     public function setAccessTokenRepository(AccessTokenRepositoryInterface $accessTokenRepository);
 
     /**
      * Set the scope repository.
      *
-     * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface $scopeRepository
+     * @param ScopeRepositoryInterface $scopeRepository
      */
     public function setScopeRepository(ScopeRepositoryInterface $scopeRepository);
 
     /**
      * Set the path to the private key.
      *
-     * @param \League\OAuth2\Server\CryptKey $privateKey
+     * @param CryptKey $privateKey
      */
     public function setPrivateKey(CryptKey $privateKey);
 
     /**
      * Set the path to the public key.
      *
-     * @param \League\OAuth2\Server\CryptKey $publicKey
+     * @param CryptKey $publicKey
      */
     public function setPublicKey(CryptKey $publicKey);
 }
diff --git a/src/Grant/ImplicitGrant.php b/src/Grant/ImplicitGrant.php
index 976acefb..62a48147 100644
--- a/src/Grant/ImplicitGrant.php
+++ b/src/Grant/ImplicitGrant.php
@@ -45,7 +45,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
     }
 
     /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
      *
      * @throw \LogicException
      */
@@ -75,11 +75,11 @@ class ImplicitGrant extends AbstractAuthorizeGrant
     /**
      * Respond to an incoming request.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface                  $request
-     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $accessTokenTTL
+     * @param ServerRequestInterface $request
+     * @param ResponseTypeInterface  $responseType
+     * @param \DateInterval          $accessTokenTTL
      *
-     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @return ResponseTypeInterface
      */
     public function respondToAccessTokenRequest(
         ServerRequestInterface $request,
@@ -151,6 +151,13 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                 : $client->getRedirectUri()
         );
 
+        // Finalize the requested scopes
+        $scopes = $this->scopeRepository->finalizeScopes(
+            $scopes,
+            $this->getIdentifier(),
+            $client
+        );
+
         $stateParameter = $this->getQueryStringParameter('state', $request);
 
         $authorizationRequest = new AuthorizationRequest();
@@ -207,7 +214,12 @@ class ImplicitGrant extends AbstractAuthorizeGrant
         // The user denied the client, redirect them back with an error
         throw OAuthServerException::accessDenied(
             'The user denied the request',
-            $finalRedirectUri
+            $this->makeRedirectUri(
+                $finalRedirectUri,
+                [
+                    'state' => $authorizationRequest->getState(),
+                ]
+            )
         );
     }
 }
diff --git a/src/Grant/PasswordGrant.php b/src/Grant/PasswordGrant.php
index 86ba1e32..31755613 100644
--- a/src/Grant/PasswordGrant.php
+++ b/src/Grant/PasswordGrant.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Grant;
 
 use League\OAuth2\Server\Entities\ClientEntityInterface;
@@ -25,8 +26,8 @@ use Psr\Http\Message\ServerRequestInterface;
 class PasswordGrant extends AbstractGrant
 {
     /**
-     * @param \League\OAuth2\Server\Repositories\UserRepositoryInterface         $userRepository
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param UserRepositoryInterface         $userRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
      */
     public function __construct(
         UserRepositoryInterface $userRepository,
@@ -66,12 +67,12 @@ class PasswordGrant extends AbstractGrant
     }
 
     /**
-     * @param \Psr\Http\Message\ServerRequestInterface             $request
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $client
+     * @param ServerRequestInterface $request
+     * @param ClientEntityInterface  $client
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \League\OAuth2\Server\Entities\UserEntityInterface
+     * @return UserEntityInterface
      */
     protected function validateUser(ServerRequestInterface $request, ClientEntityInterface $client)
     {
@@ -91,7 +92,7 @@ class PasswordGrant extends AbstractGrant
             $this->getIdentifier(),
             $client
         );
-        if (!$user instanceof UserEntityInterface) {
+        if ($user instanceof UserEntityInterface === false) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::USER_AUTHENTICATION_FAILED, $request));
 
             throw OAuthServerException::invalidCredentials();
diff --git a/src/Grant/RefreshTokenGrant.php b/src/Grant/RefreshTokenGrant.php
index d4d693a6..17448a92 100644
--- a/src/Grant/RefreshTokenGrant.php
+++ b/src/Grant/RefreshTokenGrant.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Grant;
 
 use League\OAuth2\Server\Entities\ScopeEntityInterface;
@@ -23,7 +24,7 @@ use Psr\Http\Message\ServerRequestInterface;
 class RefreshTokenGrant extends AbstractGrant
 {
     /**
-     * @param \League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface $refreshTokenRepository
+     * @param RefreshTokenRepositoryInterface $refreshTokenRepository
      */
     public function __construct(RefreshTokenRepositoryInterface $refreshTokenRepository)
     {
@@ -50,7 +51,7 @@ class RefreshTokenGrant extends AbstractGrant
             $scopes = array_map(function ($scopeId) use ($client) {
                 $scope = $this->scopeRepository->getScopeEntityByIdentifier($scopeId);
 
-                if (!$scope instanceof ScopeEntityInterface) {
+                if ($scope instanceof ScopeEntityInterface === false) {
                     // @codeCoverageIgnoreStart
                     throw OAuthServerException::invalidScope($scopeId);
                     // @codeCoverageIgnoreEnd
@@ -84,10 +85,10 @@ class RefreshTokenGrant extends AbstractGrant
     }
 
     /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param string                                   $clientId
+     * @param ServerRequestInterface $request
+     * @param string                 $clientId
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
      * @return array
      */
diff --git a/src/Middleware/AuthorizationServerMiddleware.php b/src/Middleware/AuthorizationServerMiddleware.php
index d33cbd31..a5f102fc 100644
--- a/src/Middleware/AuthorizationServerMiddleware.php
+++ b/src/Middleware/AuthorizationServerMiddleware.php
@@ -17,14 +17,12 @@ use Psr\Http\Message\ServerRequestInterface;
 class AuthorizationServerMiddleware
 {
     /**
-     * @var \League\OAuth2\Server\AuthorizationServer
+     * @var AuthorizationServer
      */
     private $server;
 
     /**
-     * AuthorizationServerMiddleware constructor.
-     *
-     * @param \League\OAuth2\Server\AuthorizationServer $server
+     * @param AuthorizationServer $server
      */
     public function __construct(AuthorizationServer $server)
     {
@@ -32,11 +30,11 @@ class AuthorizationServerMiddleware
     }
 
     /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
-     * @param callable                                 $next
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
+     * @param callable               $next
      *
-     * @return \Psr\Http\Message\ResponseInterface
+     * @return ResponseInterface
      */
     public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
     {
@@ -46,9 +44,8 @@ class AuthorizationServerMiddleware
             return $exception->generateHttpResponse($response);
             // @codeCoverageIgnoreStart
         } catch (\Exception $exception) {
-            $response->getBody()->write($exception->getMessage());
-
-            return $response->withStatus(500);
+            return (new OAuthServerException($exception->getMessage(), 0, 'unknown_error', 500))
+                ->generateHttpResponse($response);
             // @codeCoverageIgnoreEnd
         }
 
diff --git a/src/Middleware/ResourceServerMiddleware.php b/src/Middleware/ResourceServerMiddleware.php
index 6d67cb68..56d28aee 100644
--- a/src/Middleware/ResourceServerMiddleware.php
+++ b/src/Middleware/ResourceServerMiddleware.php
@@ -17,14 +17,12 @@ use Psr\Http\Message\ServerRequestInterface;
 class ResourceServerMiddleware
 {
     /**
-     * @var \League\OAuth2\Server\ResourceServer
+     * @var ResourceServer
      */
     private $server;
 
     /**
-     * ResourceServerMiddleware constructor.
-     *
-     * @param \League\OAuth2\Server\ResourceServer $server
+     * @param ResourceServer $server
      */
     public function __construct(ResourceServer $server)
     {
@@ -32,9 +30,9 @@ class ResourceServerMiddleware
     }
 
     /**
-     * @param \Psr\Http\Message\ServerRequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface      $response
-     * @param callable                                 $next
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
+     * @param callable               $next
      *
      * @return \Psr\Http\Message\ResponseInterface
      */
@@ -46,9 +44,8 @@ class ResourceServerMiddleware
             return $exception->generateHttpResponse($response);
             // @codeCoverageIgnoreStart
         } catch (\Exception $exception) {
-            $response->getBody()->write($exception->getMessage());
-
-            return $response->withStatus(500);
+            return (new OAuthServerException($exception->getMessage(), 0, 'unknown_error', 500))
+                ->generateHttpResponse($response);
             // @codeCoverageIgnoreEnd
         }
 
diff --git a/src/Repositories/AccessTokenRepositoryInterface.php b/src/Repositories/AccessTokenRepositoryInterface.php
index aab8eab8..04e98bc6 100644
--- a/src/Repositories/AccessTokenRepositoryInterface.php
+++ b/src/Repositories/AccessTokenRepositoryInterface.php
@@ -11,6 +11,7 @@ namespace League\OAuth2\Server\Repositories;
 
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\ScopeEntityInterface;
 
 /**
  * Access token interface.
@@ -20,9 +21,9 @@ interface AccessTokenRepositoryInterface extends RepositoryInterface
     /**
      * Create a new access token
      *
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface  $clientEntity
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
-     * @param mixed                                                 $userIdentifier
+     * @param ClientEntityInterface  $clientEntity
+     * @param ScopeEntityInterface[] $scopes
+     * @param mixed                  $userIdentifier
      *
      * @return AccessTokenEntityInterface
      */
@@ -31,7 +32,7 @@ interface AccessTokenRepositoryInterface extends RepositoryInterface
     /**
      * Persists a new access token to permanent storage.
      *
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessTokenEntity
+     * @param AccessTokenEntityInterface $accessTokenEntity
      */
     public function persistNewAccessToken(AccessTokenEntityInterface $accessTokenEntity);
 
diff --git a/src/Repositories/AuthCodeRepositoryInterface.php b/src/Repositories/AuthCodeRepositoryInterface.php
index cfe3b4d8..4d23439a 100644
--- a/src/Repositories/AuthCodeRepositoryInterface.php
+++ b/src/Repositories/AuthCodeRepositoryInterface.php
@@ -6,6 +6,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Repositories;
 
 use League\OAuth2\Server\Entities\AuthCodeEntityInterface;
@@ -18,14 +19,14 @@ interface AuthCodeRepositoryInterface extends RepositoryInterface
     /**
      * Creates a new AuthCode
      *
-     * @return \League\OAuth2\Server\Entities\AuthCodeEntityInterface
+     * @return AuthCodeEntityInterface
      */
     public function getNewAuthCode();
 
     /**
      * Persists a new auth code to permanent storage.
      *
-     * @param \League\OAuth2\Server\Entities\AuthCodeEntityInterface $authCodeEntity
+     * @param AuthCodeEntityInterface $authCodeEntity
      */
     public function persistNewAuthCode(AuthCodeEntityInterface $authCodeEntity);
 
diff --git a/src/Repositories/ClientRepositoryInterface.php b/src/Repositories/ClientRepositoryInterface.php
index fc56c2f3..34adf56a 100644
--- a/src/Repositories/ClientRepositoryInterface.php
+++ b/src/Repositories/ClientRepositoryInterface.php
@@ -6,8 +6,11 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Repositories;
 
+use League\OAuth2\Server\Entities\ClientEntityInterface;
+
 /**
  * Client storage interface.
  */
@@ -19,10 +22,10 @@ interface ClientRepositoryInterface extends RepositoryInterface
      * @param string      $clientIdentifier   The client's identifier
      * @param string      $grantType          The grant type used
      * @param null|string $clientSecret       The client's secret (if sent)
-     * @param bool        $mustValidateSecret If true the client must attempt to validate the secret unless the client
+     * @param bool        $mustValidateSecret If true the client must attempt to validate the secret if the client
      *                                        is confidential
      *
-     * @return \League\OAuth2\Server\Entities\ClientEntityInterface
+     * @return ClientEntityInterface
      */
     public function getClientEntity($clientIdentifier, $grantType, $clientSecret = null, $mustValidateSecret = true);
 }
diff --git a/src/Repositories/RefreshTokenRepositoryInterface.php b/src/Repositories/RefreshTokenRepositoryInterface.php
index 49d3ea4a..d7e686cc 100644
--- a/src/Repositories/RefreshTokenRepositoryInterface.php
+++ b/src/Repositories/RefreshTokenRepositoryInterface.php
@@ -6,6 +6,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Repositories;
 
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
@@ -25,7 +26,7 @@ interface RefreshTokenRepositoryInterface extends RepositoryInterface
     /**
      * Create a new refresh token_name.
      *
-     * @param \League\OAuth2\Server\Entities\RefreshTokenEntityInterface $refreshTokenEntity
+     * @param RefreshTokenEntityInterface $refreshTokenEntity
      */
     public function persistNewRefreshToken(RefreshTokenEntityInterface $refreshTokenEntity);
 
diff --git a/src/Repositories/RepositoryInterface.php b/src/Repositories/RepositoryInterface.php
index 3e50d4de..9c27b4b0 100644
--- a/src/Repositories/RepositoryInterface.php
+++ b/src/Repositories/RepositoryInterface.php
@@ -6,6 +6,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\Repositories;
 
 /**
diff --git a/src/Repositories/ScopeRepositoryInterface.php b/src/Repositories/ScopeRepositoryInterface.php
index 568f0e57..52db05de 100644
--- a/src/Repositories/ScopeRepositoryInterface.php
+++ b/src/Repositories/ScopeRepositoryInterface.php
@@ -22,7 +22,7 @@ interface ScopeRepositoryInterface extends RepositoryInterface
      *
      * @param string $identifier The scope identifier
      *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface
+     * @return ScopeEntityInterface
      */
     public function getScopeEntityByIdentifier($identifier);
 
@@ -30,12 +30,12 @@ interface ScopeRepositoryInterface extends RepositoryInterface
      * Given a client, grant type and optional user identifier validate the set of scopes requested are valid and optionally
      * append additional scopes or remove requested scopes.
      *
-     * @param ScopeEntityInterface[]                               $scopes
-     * @param string                                               $grantType
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $clientEntity
-     * @param null|string                                          $userIdentifier
+     * @param ScopeEntityInterface[] $scopes
+     * @param string                 $grantType
+     * @param ClientEntityInterface  $clientEntity
+     * @param null|string            $userIdentifier
      *
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
      */
     public function finalizeScopes(
         array $scopes,
diff --git a/src/Repositories/UserRepositoryInterface.php b/src/Repositories/UserRepositoryInterface.php
index b2de24d6..0a9efef0 100644
--- a/src/Repositories/UserRepositoryInterface.php
+++ b/src/Repositories/UserRepositoryInterface.php
@@ -10,18 +10,19 @@
 namespace League\OAuth2\Server\Repositories;
 
 use League\OAuth2\Server\Entities\ClientEntityInterface;
+use League\OAuth2\Server\Entities\UserEntityInterface;
 
 interface UserRepositoryInterface extends RepositoryInterface
 {
     /**
      * Get a user entity.
      *
-     * @param string                                               $username
-     * @param string                                               $password
-     * @param string                                               $grantType    The grant type used
-     * @param \League\OAuth2\Server\Entities\ClientEntityInterface $clientEntity
+     * @param string                $username
+     * @param string                $password
+     * @param string                $grantType    The grant type used
+     * @param ClientEntityInterface $clientEntity
      *
-     * @return \League\OAuth2\Server\Entities\UserEntityInterface
+     * @return UserEntityInterface
      */
     public function getUserEntityByUserCredentials(
         $username,
diff --git a/src/RequestEvent.php b/src/RequestEvent.php
index 42ce47b2..1558e11f 100644
--- a/src/RequestEvent.php
+++ b/src/RequestEvent.php
@@ -6,6 +6,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server;
 
 use League\Event\Event;
@@ -18,15 +19,15 @@ class RequestEvent extends Event
     const REFRESH_TOKEN_CLIENT_FAILED = 'refresh_token.client.failed';
 
     /**
-     * @var \Psr\Http\Message\ServerRequestInterface
+     * @var ServerRequestInterface
      */
     private $request;
 
     /**
      * RequestEvent constructor.
      *
-     * @param string                                   $name
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param string                 $name
+     * @param ServerRequestInterface $request
      */
     public function __construct($name, ServerRequestInterface $request)
     {
diff --git a/src/RequestTypes/AuthorizationRequest.php b/src/RequestTypes/AuthorizationRequest.php
index 2a5fcd5f..41bfb509 100644
--- a/src/RequestTypes/AuthorizationRequest.php
+++ b/src/RequestTypes/AuthorizationRequest.php
@@ -66,12 +66,14 @@ class AuthorizationRequest
 
     /**
      * The code challenge (if provided)
+     *
      * @var string
      */
     protected $codeChallenge;
 
     /**
      * The code challenge method (if provided)
+     *
      * @var string
      */
     protected $codeChallengeMethod;
@@ -125,7 +127,7 @@ class AuthorizationRequest
     }
 
     /**
-     * @return \League\OAuth2\Server\Entities\ScopeEntityInterface[]
+     * @return ScopeEntityInterface[]
      */
     public function getScopes()
     {
@@ -133,9 +135,9 @@ class AuthorizationRequest
     }
 
     /**
-     * @param \League\OAuth2\Server\Entities\ScopeEntityInterface[] $scopes
+     * @param ScopeEntityInterface[] $scopes
      */
-    public function setScopes($scopes)
+    public function setScopes(array $scopes)
     {
         $this->scopes = $scopes;
     }
diff --git a/src/ResourceServer.php b/src/ResourceServer.php
index 6fe8b1fc..5e9c13f3 100644
--- a/src/ResourceServer.php
+++ b/src/ResourceServer.php
@@ -6,34 +6,38 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server;
 
 use League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface;
 use League\OAuth2\Server\AuthorizationValidators\BearerTokenValidator;
+use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use Psr\Http\Message\ServerRequestInterface;
 
 class ResourceServer
 {
     /**
-     * @var \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface
+     * @var AccessTokenRepositoryInterface
      */
     private $accessTokenRepository;
+
     /**
-     * @var \League\OAuth2\Server\CryptKey|string
+     * @var CryptKey
      */
     private $publicKey;
+
     /**
-     * @var \League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface|null
+     * @var null|AuthorizationValidatorInterface
      */
     private $authorizationValidator;
 
     /**
      * New server instance.
      *
-     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface                  $accessTokenRepository
-     * @param \League\OAuth2\Server\CryptKey|string                                              $publicKey
-     * @param null|\League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface $authorizationValidator
+     * @param AccessTokenRepositoryInterface       $accessTokenRepository
+     * @param CryptKey|string                      $publicKey
+     * @param null|AuthorizationValidatorInterface $authorizationValidator
      */
     public function __construct(
         AccessTokenRepositoryInterface $accessTokenRepository,
@@ -42,7 +46,7 @@ class ResourceServer
     ) {
         $this->accessTokenRepository = $accessTokenRepository;
 
-        if (!$publicKey instanceof CryptKey) {
+        if ($publicKey instanceof CryptKey === false) {
             $publicKey = new CryptKey($publicKey);
         }
         $this->publicKey = $publicKey;
@@ -51,11 +55,11 @@ class ResourceServer
     }
 
     /**
-     * @return \League\OAuth2\Server\AuthorizationValidators\AuthorizationValidatorInterface
+     * @return AuthorizationValidatorInterface
      */
     protected function getAuthorizationValidator()
     {
-        if (!$this->authorizationValidator instanceof AuthorizationValidatorInterface) {
+        if ($this->authorizationValidator instanceof AuthorizationValidatorInterface === false) {
             $this->authorizationValidator = new BearerTokenValidator($this->accessTokenRepository);
         }
 
@@ -67,11 +71,11 @@ class ResourceServer
     /**
      * Determine the access token validity.
      *
-     * @param \Psr\Http\Message\ServerRequestInterface $request
+     * @param ServerRequestInterface $request
      *
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     * @throws OAuthServerException
      *
-     * @return \Psr\Http\Message\ServerRequestInterface
+     * @return ServerRequestInterface
      */
     public function validateAuthenticatedRequest(ServerRequestInterface $request)
     {
diff --git a/src/ResponseTypes/AbstractResponseType.php b/src/ResponseTypes/AbstractResponseType.php
index 02ce842b..6e164392 100644
--- a/src/ResponseTypes/AbstractResponseType.php
+++ b/src/ResponseTypes/AbstractResponseType.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\ResponseTypes;
 
 use League\OAuth2\Server\CryptTrait;
@@ -19,12 +20,12 @@ abstract class AbstractResponseType implements ResponseTypeInterface
     use CryptTrait;
 
     /**
-     * @var \League\OAuth2\Server\Entities\AccessTokenEntityInterface
+     * @var AccessTokenEntityInterface
      */
     protected $accessToken;
 
     /**
-     * @var \League\OAuth2\Server\Entities\RefreshTokenEntityInterface
+     * @var RefreshTokenEntityInterface
      */
     protected $refreshToken;
 
diff --git a/src/ResponseTypes/BearerTokenResponse.php b/src/ResponseTypes/BearerTokenResponse.php
index a65ecaae..a57573a0 100644
--- a/src/ResponseTypes/BearerTokenResponse.php
+++ b/src/ResponseTypes/BearerTokenResponse.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * OAuth 2.0 Bearer Token Type.
+ * OAuth 2.0 Bearer Token Response.
  *
  * @author      Alex Bilbie <hello@alexbilbie.com>
  * @copyright   Copyright (c) Alex Bilbie
@@ -8,8 +8,10 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\ResponseTypes;
 
+use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use Psr\Http\Message\ResponseInterface;
 
@@ -47,6 +49,8 @@ class BearerTokenResponse extends AbstractResponseType
             $responseParams['refresh_token'] = $refreshToken;
         }
 
+        $responseParams = array_merge($this->getExtraParams($this->accessToken), $responseParams);
+
         $response = $response
             ->withStatus(200)
             ->withHeader('pragma', 'no-cache')
@@ -57,4 +61,18 @@ class BearerTokenResponse extends AbstractResponseType
 
         return $response;
     }
+
+    /**
+     * Add custom fields to your Bearer Token response here, then override
+     * AuthorizationServer::getResponseType() to pull in your version of
+     * this class rather than the default.
+     *
+     * @param AccessTokenEntityInterface $accessToken
+     *
+     * @return array
+     */
+    protected function getExtraParams(AccessTokenEntityInterface $accessToken)
+    {
+        return [];
+    }
 }
diff --git a/src/ResponseTypes/RedirectResponse.php b/src/ResponseTypes/RedirectResponse.php
index 575a49e7..e4639148 100644
--- a/src/ResponseTypes/RedirectResponse.php
+++ b/src/ResponseTypes/RedirectResponse.php
@@ -1,4 +1,13 @@
 <?php
+/**
+ * OAuth 2.0 Redirect Response.
+ *
+ * @author      Alex Bilbie <hello@alexbilbie.com>
+ * @copyright   Copyright (c) Alex Bilbie
+ * @license     http://mit-license.org/
+ *
+ * @link        https://github.com/thephpleague/oauth2-server
+ */
 
 namespace League\OAuth2\Server\ResponseTypes;
 
diff --git a/src/ResponseTypes/ResponseTypeInterface.php b/src/ResponseTypes/ResponseTypeInterface.php
index a26466a7..9f358a53 100644
--- a/src/ResponseTypes/ResponseTypeInterface.php
+++ b/src/ResponseTypes/ResponseTypeInterface.php
@@ -8,6 +8,7 @@
  *
  * @link        https://github.com/thephpleague/oauth2-server
  */
+
 namespace League\OAuth2\Server\ResponseTypes;
 
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
@@ -17,12 +18,12 @@ use Psr\Http\Message\ResponseInterface;
 interface ResponseTypeInterface
 {
     /**
-     * @param \League\OAuth2\Server\Entities\AccessTokenEntityInterface $accessToken
+     * @param AccessTokenEntityInterface $accessToken
      */
     public function setAccessToken(AccessTokenEntityInterface $accessToken);
 
     /**
-     * @param \League\OAuth2\Server\Entities\RefreshTokenEntityInterface $refreshToken
+     * @param RefreshTokenEntityInterface $refreshToken
      */
     public function setRefreshToken(RefreshTokenEntityInterface $refreshToken);
 
diff --git a/tests/AuthorizationServerTest.php b/tests/AuthorizationServerTest.php
index 2303b713..909da159 100644
--- a/tests/AuthorizationServerTest.php
+++ b/tests/AuthorizationServerTest.php
@@ -29,9 +29,9 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
     public function testRespondToRequestInvalidGrantType()
     {
         $server = new AuthorizationServer(
-            $this->getMock(ClientRepositoryInterface::class),
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(ClientRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/private.key',
             'file://' . __DIR__ . '/Stubs/public.key',
             new StubResponseType()
@@ -49,13 +49,13 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
 
     public function testRespondToRequest()
     {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepository->method('getClientEntity')->willReturn(new ClientEntity());
 
         $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
         $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
 
-        $accessTokenRepositoryMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
         $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
 
         $server = new AuthorizationServer(
@@ -78,12 +78,12 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
 
     public function testGetResponseType()
     {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
 
         $server = new AuthorizationServer(
             $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/private.key',
             'file://' . __DIR__ . '/Stubs/public.key'
         );
@@ -97,12 +97,12 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
 
     public function testCompleteAuthorizationRequest()
     {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
 
         $server = new AuthorizationServer(
             $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/private.key',
             'file://' . __DIR__ . '/Stubs/public.key'
         );
@@ -112,7 +112,7 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
 
         $grant = new AuthCodeGrant(
             $authCodeRepository,
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
 
@@ -139,16 +139,16 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
 
         $server = new AuthorizationServer(
             $clientRepositoryMock,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/private.key',
             'file://' . __DIR__ . '/Stubs/public.key'
         );
@@ -178,9 +178,9 @@ class AuthorizationServerTest extends \PHPUnit_Framework_TestCase
     public function testValidateAuthorizationRequestUnregistered()
     {
         $server = new AuthorizationServer(
-            $this->getMock(ClientRepositoryInterface::class),
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(ClientRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/private.key',
             'file://' . __DIR__ . '/Stubs/public.key'
         );
diff --git a/tests/CryptKeyTest.php b/tests/CryptKeyTest.php
new file mode 100644
index 00000000..c7f7f4a0
--- /dev/null
+++ b/tests/CryptKeyTest.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace LeagueTests\Utils;
+
+use League\OAuth2\Server\CryptKey;
+
+class CryptKeyTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @expectedException \LogicException
+     */
+    public function testNoFile()
+    {
+        new CryptKey('undefined file');
+    }
+
+    public function testKeyCreation()
+    {
+        $keyFile = __DIR__ . '/Stubs/public.key';
+        $key = new CryptKey($keyFile, 'secret');
+
+        $this->assertEquals('file://' . $keyFile, $key->getKeyPath());
+        $this->assertEquals('secret', $key->getPassPhrase());
+    }
+
+    public function testKeyFileCreation()
+    {
+        $keyContent = file_get_contents(__DIR__ . '/Stubs/public.key');
+        $key = new CryptKey($keyContent);
+
+        $this->assertEquals(
+            'file://' . sys_get_temp_dir() . '/' . sha1($keyContent) . '.key',
+            $key->getKeyPath()
+        );
+    }
+}
diff --git a/tests/Grant/AbstractGrantTest.php b/tests/Grant/AbstractGrantTest.php
index 0c4f6ae7..3ef3f133 100644
--- a/tests/Grant/AbstractGrantTest.php
+++ b/tests/Grant/AbstractGrantTest.php
@@ -32,6 +32,76 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
         $grantMock->setEmitter(new Emitter());
     }
 
+    public function testHttpBasicWithPassword()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('Open:Sesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame(['Open', 'Sesame'], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNoPassword()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('Open:'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame(['Open', ''], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNotBasic()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Foo ' . base64_encode('Open:Sesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNotBase64()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ||');
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
+    public function testHttpBasicNoColon()
+    {
+        /** @var AbstractGrant $grantMock */
+        $grantMock = $this->getMockForAbstractClass(AbstractGrant::class);
+        $abstractGrantReflection = new \ReflectionClass($grantMock);
+
+        $serverRequest = new ServerRequest();
+        $serverRequest = $serverRequest->withHeader('Authorization', 'Basic ' . base64_encode('OpenSesame'));
+        $basicAuthMethod = $abstractGrantReflection->getMethod('getBasicAuthCredentials');
+        $basicAuthMethod->setAccessible(true);
+
+        $this->assertSame([null, null], $basicAuthMethod->invoke($grantMock, $serverRequest));
+    }
+
     public function testValidateClientPublic()
     {
         $client = new ClientEntity();
@@ -256,7 +326,7 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
 
     public function testIssueRefreshToken()
     {
-        $refreshTokenRepoMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $refreshTokenRepoMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
         $refreshTokenRepoMock
             ->expects($this->once())
             ->method('getNewRefreshToken')
@@ -275,13 +345,12 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
         /** @var RefreshTokenEntityInterface $refreshToken */
         $refreshToken = $issueRefreshTokenMethod->invoke($grantMock, $accessToken);
         $this->assertTrue($refreshToken instanceof RefreshTokenEntityInterface);
-        $this->assertFalse($refreshToken->isExpired());
         $this->assertEquals($accessToken, $refreshToken->getAccessToken());
     }
 
     public function testIssueAccessToken()
     {
-        $accessTokenRepoMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessTokenRepoMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
         $accessTokenRepoMock->method('getNewToken')->willReturn(new AccessTokenEntity());
 
         /** @var AbstractGrant $grantMock */
@@ -301,12 +370,11 @@ class AbstractGrantTest extends \PHPUnit_Framework_TestCase
             [new ScopeEntity()]
         );
         $this->assertTrue($accessToken instanceof AccessTokenEntityInterface);
-        $this->assertFalse($accessToken->isExpired());
     }
 
     public function testIssueAuthCode()
     {
-        $authCodeRepoMock = $this->getMock(AuthCodeRepositoryInterface::class);
+        $authCodeRepoMock = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
         $authCodeRepoMock->expects($this->once())->method('getNewAuthCode')->willReturn(new AuthCodeEntity());
 
         /** @var AbstractGrant $grantMock */
diff --git a/tests/Grant/AuthCodeGrantTest.php b/tests/Grant/AuthCodeGrantTest.php
index 09ea03e6..498fdb4e 100644
--- a/tests/Grant/AuthCodeGrantTest.php
+++ b/tests/Grant/AuthCodeGrantTest.php
@@ -6,6 +6,7 @@ use League\OAuth2\Server\CryptKey;
 use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\RefreshTokenEntityInterface;
 use League\OAuth2\Server\Exception\OAuthServerException;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;
 use League\OAuth2\Server\Grant\AuthCodeGrant;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\AuthCodeRepositoryInterface;
@@ -39,8 +40,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
     public function testGetIdentifier()
     {
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
 
@@ -50,8 +51,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
     public function testCanRespondToAuthorizationRequest()
     {
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
 
@@ -80,8 +81,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -92,9 +93,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type' => 'code',
                 'client_id'     => 'foo',
                 'redirect_uri'  => 'http://foo/bar',
@@ -112,8 +113,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -124,9 +125,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type' => 'code',
                 'client_id'     => 'foo',
                 'redirect_uri'  => 'http://foo/bar',
@@ -136,7 +137,6 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue($grant->validateAuthorizationRequest($request) instanceof AuthorizationRequest);
     }
 
-
     public function testValidateAuthorizationRequestCodeChallenge()
     {
         $client = new ClientEntity();
@@ -145,8 +145,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -158,9 +158,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type'  => 'code',
                 'client_id'      => 'foo',
                 'redirect_uri'   => 'http://foo/bar',
@@ -180,8 +180,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -212,8 +212,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn(null);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -247,8 +247,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -259,9 +259,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type' => 'code',
                 'client_id'     => 'foo',
                 'redirect_uri'  => 'http://bar',
@@ -283,8 +283,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -295,9 +295,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type' => 'code',
                 'client_id'     => 'foo',
                 'redirect_uri'  => 'http://bar',
@@ -319,8 +319,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -332,9 +332,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type' => 'code',
                 'client_id'     => 'foo',
                 'redirect_uri'  => 'http://foo/bar',
@@ -356,8 +356,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -369,9 +369,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             null,
             null,
             'php://input',
-            $headers = [],
-            $cookies = [],
-            $queryParams = [
+            [],
+            [],
+            [
                 'response_type'         => 'code',
                 'client_id'             => 'foo',
                 'redirect_uri'          => 'http://foo/bar',
@@ -396,7 +396,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new AuthCodeGrant(
             $authCodeRepository,
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
 
@@ -423,7 +423,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new AuthCodeGrant(
             $authCodeRepository,
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
 
@@ -455,8 +455,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -523,8 +523,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -595,8 +595,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -651,20 +651,18 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
      */
     public function testRespondToAccessTokenRequestMissingRedirectUri()
     {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
         $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
-        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
-        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
-        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
         $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
-        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
 
         $request = new ServerRequest(
             [],
@@ -676,11 +674,69 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             [],
             [],
             [
+                'client_id'  => 'foo',
                 'grant_type' => 'authorization_code',
+                'code'       => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id'          => uniqid(),
+                            'expire_time'           => time() + 3600,
+                            'client_id'             => 'foo',
+                            'redirect_uri'          => 'http://foo/bar',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 3
+     */
+    public function testRespondToAccessTokenRequestRedirectUriMismatch()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'client_id'  => 'foo',
+                'grant_type' => 'authorization_code',
+                'redirect_uri' => 'http://bar/foo',
+                'code'       => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id'          => uniqid(),
+                            'expire_time'           => time() + 3600,
+                            'client_id'             => 'foo',
+                            'redirect_uri'          => 'http://foo/bar',
+                        ]
+                    )
+                ),
             ]
         );
 
-        /* @var StubResponseType $response */
         $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
     }
 
@@ -699,8 +755,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -745,8 +801,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -810,7 +866,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant = new AuthCodeGrant(
             $authCodeRepositoryMock,
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -870,8 +926,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -931,8 +987,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willReturnSelf();
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->setClientRepository($clientRepositoryMock);
@@ -988,8 +1044,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -1038,7 +1094,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             $this->assertEquals($e->getHint(), 'Failed to verify `code_verifier`.');
         }
     }
-    
+
     public function testRespondToAccessTokenRequestBadCodeVerifierS256()
     {
         $client = new ClientEntity();
@@ -1061,8 +1117,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -1134,8 +1190,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
         $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
 
         $grant = new AuthCodeGrant(
-            $this->getMock(AuthCodeRepositoryInterface::class),
-            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
             new \DateInterval('PT10M')
         );
         $grant->enableCodeExchangeProof();
@@ -1183,4 +1239,313 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             $this->assertEquals($e->getHint(), 'Check the `code_verifier` parameter');
         }
     }
-}
\ No newline at end of file
+
+    public function testAuthCodeRepositoryUniqueConstraintCheck()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        $authCodeRepository = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
+        $authCodeRepository->method('getNewAuthCode')->willReturn(new AuthCodeEntity());
+
+        $authCodeRepository->expects($this->at(0))->method('persistNewAuthCode')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+        $authCodeRepository->expects($this->at(1))->method('persistNewAuthCode');
+
+        $grant = new AuthCodeGrant(
+            $authCodeRepository,
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 7
+     */
+    public function testAuthCodeRepositoryFailToPersist()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        $authCodeRepository = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
+        $authCodeRepository->method('getNewAuthCode')->willReturn(new AuthCodeEntity());
+        $authCodeRepository->method('persistNewAuthCode')->willThrowException(OAuthServerException::serverError('something bad happened'));
+
+        $grant = new AuthCodeGrant(
+            $authCodeRepository,
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException
+     * @expectedExceptionCode 100
+     */
+    public function testAuthCodeRepositoryFailToPersistUniqueNoInfiniteLoop()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        $authCodeRepository = $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock();
+        $authCodeRepository->method('getNewAuthCode')->willReturn(new AuthCodeEntity());
+        $authCodeRepository->method('persistNewAuthCode')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+
+        $grant = new AuthCodeGrant(
+            $authCodeRepository,
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+    }
+
+    public function testRefreshTokenRepositoryUniqueConstraintCheck()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+        $refreshTokenRepositoryMock->expects($this->at(0))->method('persistNewRefreshToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+        $refreshTokenRepositoryMock->expects($this->at(1))->method('persistNewRefreshToken');
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'grant_type'   => 'authorization_code',
+                'client_id'    => 'foo',
+                'redirect_uri' => 'http://foo/bar',
+                'code'         => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id' => uniqid(),
+                            'expire_time'  => time() + 3600,
+                            'client_id'    => 'foo',
+                            'user_id'      => 123,
+                            'scopes'       => ['foo'],
+                            'redirect_uri' => 'http://foo/bar',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        /** @var StubResponseType $response */
+        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response->getAccessToken() instanceof AccessTokenEntityInterface);
+        $this->assertTrue($response->getRefreshToken() instanceof RefreshTokenEntityInterface);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 7
+     */
+    public function testRefreshTokenRepositoryFailToPersist()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willThrowException(OAuthServerException::serverError('something bad happened'));
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'grant_type'   => 'authorization_code',
+                'client_id'    => 'foo',
+                'redirect_uri' => 'http://foo/bar',
+                'code'         => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id' => uniqid(),
+                            'expire_time'  => time() + 3600,
+                            'client_id'    => 'foo',
+                            'user_id'      => 123,
+                            'scopes'       => ['foo'],
+                            'redirect_uri' => 'http://foo/bar',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        /** @var StubResponseType $response */
+        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response->getAccessToken() instanceof AccessTokenEntityInterface);
+        $this->assertTrue($response->getRefreshToken() instanceof RefreshTokenEntityInterface);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException
+     * @expectedExceptionCode 100
+     */
+    public function testRefreshTokenRepositoryFailToPersistUniqueNoInfiniteLoop()
+    {
+        $client = new ClientEntity();
+        $client->setIdentifier('foo');
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willReturnSelf();
+
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock->method('getNewRefreshToken')->willReturn(new RefreshTokenEntity());
+        $refreshTokenRepositoryMock->method('persistNewRefreshToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+
+        $request = new ServerRequest(
+            [],
+            [],
+            null,
+            'POST',
+            'php://input',
+            [],
+            [],
+            [],
+            [
+                'grant_type'   => 'authorization_code',
+                'client_id'    => 'foo',
+                'redirect_uri' => 'http://foo/bar',
+                'code'         => $this->cryptStub->doEncrypt(
+                    json_encode(
+                        [
+                            'auth_code_id' => uniqid(),
+                            'expire_time'  => time() + 3600,
+                            'client_id'    => 'foo',
+                            'user_id'      => 123,
+                            'scopes'       => ['foo'],
+                            'redirect_uri' => 'http://foo/bar',
+                        ]
+                    )
+                ),
+            ]
+        );
+
+        /** @var StubResponseType $response */
+        $response = $grant->respondToAccessTokenRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response->getAccessToken() instanceof AccessTokenEntityInterface);
+        $this->assertTrue($response->getRefreshToken() instanceof RefreshTokenEntityInterface);
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testCompleteAuthorizationRequestNoUser()
+    {
+        $grant = new AuthCodeGrant(
+            $this->getMockBuilder(AuthCodeRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock(),
+            new \DateInterval('PT10M')
+        );
+
+        $grant->completeAuthorizationRequest(new AuthorizationRequest());
+    }
+}
diff --git a/tests/Grant/ImplicitGrantTest.php b/tests/Grant/ImplicitGrantTest.php
index fbf60b8c..0fc06370 100644
--- a/tests/Grant/ImplicitGrantTest.php
+++ b/tests/Grant/ImplicitGrantTest.php
@@ -3,14 +3,19 @@
 namespace LeagueTests\Grant;
 
 use League\OAuth2\Server\CryptKey;
+use League\OAuth2\Server\Exception\OAuthServerException;
+use League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException;
 use League\OAuth2\Server\Grant\ImplicitGrant;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
+use League\OAuth2\Server\Repositories\RefreshTokenRepositoryInterface;
+use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 use League\OAuth2\Server\RequestTypes\AuthorizationRequest;
 use League\OAuth2\Server\ResponseTypes\RedirectResponse;
 use LeagueTests\Stubs\AccessTokenEntity;
 use LeagueTests\Stubs\ClientEntity;
 use LeagueTests\Stubs\CryptTraitStub;
+use LeagueTests\Stubs\ScopeEntity;
 use LeagueTests\Stubs\StubResponseType;
 use LeagueTests\Stubs\UserEntity;
 use Zend\Diactoros\ServerRequest;
@@ -83,8 +88,14 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
         $grant = new ImplicitGrant(new \DateInterval('PT10M'));
         $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
 
         $request = new ServerRequest(
             [],
@@ -111,8 +122,14 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
         $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepositoryMock->method('getClientEntity')->willReturn($client);
 
+        $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
+        $scopeEntity = new ScopeEntity();
+        $scopeRepositoryMock->method('getScopeEntityByIdentifier')->willReturn($scopeEntity);
+        $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
+
         $grant = new ImplicitGrant(new \DateInterval('PT10M'));
         $grant->setClientRepository($clientRepositoryMock);
+        $grant->setScopeRepository($scopeRepositoryMock);
 
         $request = new ServerRequest(
             [],
@@ -295,4 +312,104 @@ class ImplicitGrantTest extends \PHPUnit_Framework_TestCase
 
         $grant->completeAuthorizationRequest($authRequest);
     }
+
+    public function testAccessTokenRepositoryUniqueConstraintCheck()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->expects($this->at(0))->method('persistNewAccessToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+        $accessTokenRepositoryMock->expects($this->at(1))->method('persistNewAccessToken')->willReturnSelf();
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $this->assertTrue($grant->completeAuthorizationRequest($authRequest) instanceof RedirectResponse);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 7
+     */
+    public function testAccessTokenRepositoryFailToPersist()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willThrowException(OAuthServerException::serverError('something bad happened'));
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $grant->completeAuthorizationRequest($authRequest);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\UniqueTokenIdentifierConstraintViolationException
+     * @expectedExceptionCode 100
+     */
+    public function testAccessTokenRepositoryFailToPersistUniqueNoInfiniteLoop()
+    {
+        $authRequest = new AuthorizationRequest();
+        $authRequest->setAuthorizationApproved(true);
+        $authRequest->setClient(new ClientEntity());
+        $authRequest->setGrantTypeId('authorization_code');
+        $authRequest->setUser(new UserEntity());
+
+        /** @var AccessTokenRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject $accessTokenRepositoryMock */
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+        $accessTokenRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
+        $accessTokenRepositoryMock->method('persistNewAccessToken')->willThrowException(UniqueTokenIdentifierConstraintViolationException::create());
+
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $grant->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+        $grant->setAccessTokenRepository($accessTokenRepositoryMock);
+
+        $grant->completeAuthorizationRequest($authRequest);
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testSetRefreshTokenTTL()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->setRefreshTokenTTL(new \DateInterval('PT10M'));
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testSetRefreshTokenRepository()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
+        $grant->setRefreshTokenRepository($refreshTokenRepositoryMock);
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testCompleteAuthorizationRequestNoUser()
+    {
+        $grant = new ImplicitGrant(new \DateInterval('PT10M'));
+        $grant->completeAuthorizationRequest(new AuthorizationRequest());
+    }
 }
diff --git a/tests/Grant/PasswordGrantTest.php b/tests/Grant/PasswordGrantTest.php
index 20f2ce2b..b380bfb2 100644
--- a/tests/Grant/PasswordGrantTest.php
+++ b/tests/Grant/PasswordGrantTest.php
@@ -21,8 +21,8 @@ class PasswordGrantTest extends \PHPUnit_Framework_TestCase
 {
     public function testGetIdentifier()
     {
-        $userRepositoryMock = $this->getMock(UserRepositoryInterface::class);
-        $refreshTokenRepositoryMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
 
         $grant = new PasswordGrant($userRepositoryMock, $refreshTokenRepositoryMock);
         $this->assertEquals('password', $grant->getIdentifier());
diff --git a/tests/Grant/RefreshTokenGrantTest.php b/tests/Grant/RefreshTokenGrantTest.php
index af3d477f..90a63276 100644
--- a/tests/Grant/RefreshTokenGrantTest.php
+++ b/tests/Grant/RefreshTokenGrantTest.php
@@ -32,7 +32,7 @@ class RefreshTokenGrantTest extends \PHPUnit_Framework_TestCase
 
     public function testGetIdentifier()
     {
-        $refreshTokenRepositoryMock = $this->getMock(RefreshTokenRepositoryInterface::class);
+        $refreshTokenRepositoryMock = $this->getMockBuilder(RefreshTokenRepositoryInterface::class)->getMock();
 
         $grant = new RefreshTokenGrant($refreshTokenRepositoryMock);
         $this->assertEquals('refresh_token', $grant->getIdentifier());
diff --git a/tests/Middleware/AuthorizationServerMiddlewareTest.php b/tests/Middleware/AuthorizationServerMiddlewareTest.php
index bb068179..affc2a3b 100644
--- a/tests/Middleware/AuthorizationServerMiddlewareTest.php
+++ b/tests/Middleware/AuthorizationServerMiddlewareTest.php
@@ -19,13 +19,13 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
 {
     public function testValidResponse()
     {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepository->method('getClientEntity')->willReturn(new ClientEntity());
 
         $scopeRepositoryMock = $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock();
         $scopeRepositoryMock->method('finalizeScopes')->willReturnArgument(0);
 
-        $accessRepositoryMock = $this->getMock(AccessTokenRepositoryInterface::class);
+        $accessRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
         $accessRepositoryMock->method('getNewToken')->willReturn(new AccessTokenEntity());
 
         $server = new AuthorizationServer(
@@ -58,13 +58,13 @@ class AuthorizationServerMiddlewareTest extends \PHPUnit_Framework_TestCase
 
     public function testOAuthErrorResponse()
     {
-        $clientRepository = $this->getMock(ClientRepositoryInterface::class);
+        $clientRepository = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
         $clientRepository->method('getClientEntity')->willReturn(null);
 
         $server = new AuthorizationServer(
             $clientRepository,
-            $this->getMock(AccessTokenRepositoryInterface::class),
-            $this->getMock(ScopeRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
+            $this->getMockBuilder(ScopeRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/../Stubs/private.key',
             'file://' . __DIR__ . '/../Stubs/public.key',
             new StubResponseType()
diff --git a/tests/Middleware/ResourceServerMiddlewareTest.php b/tests/Middleware/ResourceServerMiddlewareTest.php
index e91e9b9b..549c8003 100644
--- a/tests/Middleware/ResourceServerMiddlewareTest.php
+++ b/tests/Middleware/ResourceServerMiddlewareTest.php
@@ -16,7 +16,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
     public function testValidResponse()
     {
         $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/../Stubs/public.key'
         );
 
@@ -51,7 +51,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
     public function testValidResponseExpiredToken()
     {
         $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/../Stubs/public.key'
         );
 
@@ -86,7 +86,7 @@ class ResourceServerMiddlewareTest extends \PHPUnit_Framework_TestCase
     public function testErrorResponse()
     {
         $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/../Stubs/public.key'
         );
 
diff --git a/tests/ResourceServerTest.php b/tests/ResourceServerTest.php
index c1dafe27..8a3353cc 100644
--- a/tests/ResourceServerTest.php
+++ b/tests/ResourceServerTest.php
@@ -13,7 +13,7 @@ class ResourceServerTest extends \PHPUnit_Framework_TestCase
     public function testValidateAuthenticatedRequest()
     {
         $server = new ResourceServer(
-            $this->getMock(AccessTokenRepositoryInterface::class),
+            $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock(),
             'file://' . __DIR__ . '/Stubs/public.key'
         );
 
diff --git a/tests/ResponseTypes/BearerResponseTypeTest.php b/tests/ResponseTypes/BearerResponseTypeTest.php
index 6c84e148..ca660ab7 100644
--- a/tests/ResponseTypes/BearerResponseTypeTest.php
+++ b/tests/ResponseTypes/BearerResponseTypeTest.php
@@ -61,6 +61,53 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
         $this->assertTrue(isset($json->refresh_token));
     }
 
+    public function testGenerateHttpResponseWithExtraParams()
+    {
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $responseType = new BearerTokenResponseWithParams($accessTokenRepositoryMock);
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $client = new ClientEntity();
+        $client->setIdentifier('clientName');
+
+        $scope = new ScopeEntity();
+        $scope->setIdentifier('basic');
+
+        $accessToken = new AccessTokenEntity();
+        $accessToken->setIdentifier('abcdef');
+        $accessToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('PT1H')));
+        $accessToken->setClient($client);
+        $accessToken->addScope($scope);
+
+        $refreshToken = new RefreshTokenEntity();
+        $refreshToken->setIdentifier('abcdef');
+        $refreshToken->setAccessToken($accessToken);
+        $refreshToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('PT1H')));
+
+        $responseType->setAccessToken($accessToken);
+        $responseType->setRefreshToken($refreshToken);
+
+        $response = $responseType->generateHttpResponse(new Response());
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertEquals('no-cache', $response->getHeader('pragma')[0]);
+        $this->assertEquals('no-store', $response->getHeader('cache-control')[0]);
+        $this->assertEquals('application/json; charset=UTF-8', $response->getHeader('content-type')[0]);
+
+        $response->getBody()->rewind();
+        $json = json_decode($response->getBody()->getContents());
+        $this->assertEquals('Bearer', $json->token_type);
+        $this->assertTrue(isset($json->expires_in));
+        $this->assertTrue(isset($json->access_token));
+        $this->assertTrue(isset($json->refresh_token));
+
+        $this->assertTrue(isset($json->foo));
+        $this->assertEquals('bar', $json->foo);
+    }
+
     public function testDetermineAccessTokenInHeaderValidToken()
     {
         $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
@@ -226,4 +273,31 @@ class BearerResponseTypeTest extends \PHPUnit_Framework_TestCase
             );
         }
     }
+
+    public function testDetermineMissingBearerInHeader()
+    {
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $responseType = new BearerTokenResponse($accessTokenRepositoryMock);
+        $responseType->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $responseType->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $accessTokenRepositoryMock = $this->getMockBuilder(AccessTokenRepositoryInterface::class)->getMock();
+
+        $authorizationValidator = new BearerTokenValidator($accessTokenRepositoryMock);
+        $authorizationValidator->setPrivateKey(new CryptKey('file://' . __DIR__ . '/../Stubs/private.key'));
+        $authorizationValidator->setPublicKey(new CryptKey('file://' . __DIR__ . '/../Stubs/public.key'));
+
+        $request = new ServerRequest();
+        $request = $request->withHeader('authorization', 'Bearer blah.blah.blah');
+
+        try {
+            $authorizationValidator->validateAuthorization($request);
+        } catch (OAuthServerException $e) {
+            $this->assertEquals(
+                'Error while decoding to JSON',
+                $e->getHint()
+            );
+        }
+    }
 }
diff --git a/tests/ResponseTypes/BearerTokenResponseWithParams.php b/tests/ResponseTypes/BearerTokenResponseWithParams.php
new file mode 100644
index 00000000..4ba09f4b
--- /dev/null
+++ b/tests/ResponseTypes/BearerTokenResponseWithParams.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace LeagueTests\ResponseTypes;
+
+use League\OAuth2\Server\Entities\AccessTokenEntityInterface;
+use League\OAuth2\Server\ResponseTypes\BearerTokenResponse;
+
+class BearerTokenResponseWithParams extends BearerTokenResponse
+{
+    protected function getExtraParams(AccessTokenEntityInterface $accessToken)
+    {
+        return ['foo' => 'bar', 'token_type' => 'Should not overwrite'];
+    }
+}