diff --git a/tests/Grant/AuthCodeGrantTest.php b/tests/Grant/AuthCodeGrantTest.php
index 41979461..faf18318 100644
--- a/tests/Grant/AuthCodeGrantTest.php
+++ b/tests/Grant/AuthCodeGrantTest.php
@@ -23,7 +23,9 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             $this->getMock(AuthCodeRepositoryInterface::class),
             $this->getMock(RefreshTokenRepositoryInterface::class),
             $this->getMock(UserRepositoryInterface::class),
-            new \DateInterval('PT10M')
+            new \DateInterval('PT10M'),
+            '',
+            ''
         );
 
         $this->assertEquals('authorization_code', $grant->getIdentifier());
@@ -49,7 +51,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             $cookies = [],
             $queryParams = [
                 'response_type' => 'code',
-                'client_id'     => 'foo'
+                'client_id'     => 'foo',
             ]
         );
 
@@ -76,8 +78,8 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             ''
         );
         $grant->setClientRepository($clientRepositoryMock);
-        $grant->setPathToPublicKey('file://'.__DIR__.'/../Utils/public.key');
-        $grant->setPathToPrivateKey('file://'.__DIR__.'/../Utils/private.key');
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
 
         $request = new ServerRequest(
             [
@@ -93,8 +95,187 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             [
                 'oauth_authorize_request' => KeyCrypt::encrypt(
                     json_encode(['user_id' => 123]),
-                    'file://'.__DIR__.'/../Utils/private.key'
-                )
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+                'state'         => 'foobar',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'approve',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertTrue(strstr($response->getHeader('location')[0], 'http://foo/bar') !== false);
+    }
+
+    public function testRespondToAuthorizationRequestUserDenied()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M'),
+            '',
+            ''
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => 123]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+                'state'         => 'foobar',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'denied',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertTrue(strstr($response->getHeader('location')[0], 'http://foo/bar') !== false);
+        $this->assertTrue(strstr($response->getHeader('location')[0], 'access_denied') !== false);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 3
+     */
+    public function testRespondToAuthorizationRequestMissingClientId()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M'),
+            '',
+            ''
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => 123]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'approve',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+    }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 4
+     */
+    public function testRespondToAuthorizationRequestBadClient()
+    {
+        $client = null;
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M'),
+            '',
+            ''
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => 123]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
             ],
             [
                 'response_type' => 'code',
@@ -103,7 +284,7 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
             [
                 'username' => 'alex',
                 'password' => 'whisky',
-                'action'   => 'approve'
+                'action'   => 'approve',
             ]
         );
 
@@ -111,4 +292,228 @@ class AuthCodeGrantTest extends \PHPUnit_Framework_TestCase
 
         $this->assertTrue($response instanceof ResponseInterface);
     }
+
+    /**
+     * @expectedException \League\OAuth2\Server\Exception\OAuthServerException
+     * @expectedExceptionCode 7
+     */
+    public function testRespondToAuthorizationRequestBadCookie()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M'),
+            '',
+            ''
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => 'blah',
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'approve',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+    }
+
+    public function testRespondToAuthorizationRequestTryLogin()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M'),
+            '',
+            ''
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => null]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'approve',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertTrue(strstr($response->getHeader('location')[0], 'http://foo/bar') !== false);
+    }
+
+    public function testRespondToAuthorizationRequestShowLoginForm()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = null;
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => null]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+                'action'   => 'approve',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertTrue(strstr($response->getHeader('content-type')[0], 'text/html') !== false);
+        $this->assertTrue(strstr($response->getBody()->getContents(), 'Incorrect username or password') !== false);
+    }
+
+    public function testRespondToAuthorizationRequestShowAuthorizeForm()
+    {
+        $client = new ClientEntity();
+        $client->setRedirectUri('http://foo/bar');
+        $clientRepositoryMock = $this->getMockBuilder(ClientRepositoryInterface::class)->getMock();
+        $clientRepositoryMock->method('getClientEntity')->willReturn($client);
+
+        $userRepositoryMock = $this->getMockBuilder(UserRepositoryInterface::class)->getMock();
+        $userEntity = new UserEntity();
+        $userRepositoryMock->method('getUserEntityByUserCredentials')->willReturn($userEntity);
+
+        $grant = new AuthCodeGrant(
+            $this->getMock(AuthCodeRepositoryInterface::class),
+            $this->getMock(RefreshTokenRepositoryInterface::class),
+            $userRepositoryMock,
+            new \DateInterval('PT10M')
+        );
+        $grant->setClientRepository($clientRepositoryMock);
+        $grant->setPathToPublicKey('file://' . __DIR__ . '/../Utils/public.key');
+        $grant->setPathToPrivateKey('file://' . __DIR__ . '/../Utils/private.key');
+
+        $request = new ServerRequest(
+            [
+                'HTTP_HOST'   => 'auth-server.tld',
+                'REQUEST_URI' => '/authorize',
+            ],
+            []
+            ,
+            null,
+            'POST',
+            'php://input',
+            [],
+            [
+                'oauth_authorize_request' => KeyCrypt::encrypt(
+                    json_encode(['user_id' => 123]),
+                    'file://' . __DIR__ . '/../Utils/private.key'
+                ),
+            ],
+            [
+                'response_type' => 'code',
+                'client_id'     => 'foo',
+            ],
+            [
+                'username' => 'alex',
+                'password' => 'whisky',
+            ]
+        );
+
+        $response = $grant->respondToRequest($request, new StubResponseType(), new \DateInterval('PT10M'));
+
+        $this->assertTrue($response instanceof ResponseInterface);
+        $this->assertTrue(strstr($response->getHeader('set-cookie')[0], 'oauth_authorize_request') !== false);
+    }
 }