diff --git a/tests/authentication/AuthServerTest.php b/tests/authentication/AuthServerTest.php
index f5f534cd..a6b2b1b3 100644
--- a/tests/authentication/AuthServerTest.php
+++ b/tests/authentication/AuthServerTest.php
@@ -595,627 +595,6 @@ class Authentication_Server_test extends PHPUnit_Framework_TestCase
         $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
     }
 
-    public function test_issueAccessToken_with_refresh_token()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('updateSession')->andReturn(null);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\AuthCode());
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $_POST['grant_type'] = 'authorization_code';
-        $_POST['client_id'] = 1234;
-        $_POST['client_secret'] = 5678;
-        $_POST['redirect_uri'] = 'http://foo/redirect';
-        $_POST['code'] = 'foobar';
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken();
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_refreshTokenGrant_missingClientId()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token'
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_refreshTokenGrant_missingClientSecret()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token',
-            'client_id' =>  1234
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    8
-     */
-    public function test_issueAccessToken_refreshTokenGrant_badClient()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(false);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token',
-            'client_id' =>  1234,
-            'client_secret' =>  5678
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_refreshTokenGrant_missingRefreshToken()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array());
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            //'refresh_token' =>
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_refreshTokenGrant_badRefreshToken()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array());
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(false);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'refresh_token' =>  'abcdef'
-        ));
-    }
-
-    public function test_issueAccessToken_refreshTokenGrant_passedInput()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('updateSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $_POST['grant_type'] = 'refresh_token';
-        $_POST['client_id'] = 1234;
-        $_POST['client_secret'] = 5678;
-        $_POST['refresh_token'] = 'abcdef';
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken();
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    public function test_issueAccessToken_refreshTokenGrant()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('updateSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\RefreshToken());
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'refresh_token',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'refresh_token'  =>  'abcdef',
-        ));
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_clientCredentialsGrant_missingClientId()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'client_credentials'
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_clientCredentialsGrant_missingClientPassword()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'client_credentials',
-            'client_id' =>  1234
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    8
-     */
-    public function test_issueAccessToken_clientCredentialsGrant_badClient()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(false);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'client_credentials',
-            'client_id' =>  1234,
-            'client_secret' =>  5678
-        ));
-    }
-
-    function test_issueAccessToken_clientCredentialsGrant_passedInput()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'client_credentials',
-            'client_id' =>  1234,
-            'client_secret' =>  5678
-        ));
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    function test_issueAccessToken_clientCredentialsGrant()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
-
-        $_POST['grant_type'] = 'client_credentials';
-        $_POST['client_id'] = 1234;
-        $_POST['client_secret'] = 5678;
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken();
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_passwordGrant_missingClientId()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\Password());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'client_credentials'
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    public function test_issueAccessToken_passwordGrant_missingClientPassword()
-    {
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\Password());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    8
-     */
-    public function test_issueAccessToken_passwordGrant_badClient()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(false);
-
-        $a = $this->returnDefault();
-        $a->addGrantType(new OAuth2\Grant\Password());
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\InvalidGrantTypeException
-     */
-    function test_issueAccessToken_passwordGrant_invalidCallback()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = null;
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'username'  => 'foo',
-            'password'  => 'bar'
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    function test_issueAccessToken_passwordGrant_missingUsername()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = function($u, $p) { return false; };
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    function test_issueAccessToken_passwordGrant_missingPassword()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = function($u, $p) { return false; };
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'username'  =>  'foo'
-        ));
-    }
-
-    /**
-     * @expectedException        OAuth2\Exception\ClientException
-     * @expectedExceptionCode    0
-     */
-    function test_issueAccessToken_passwordGrant_badCredentials()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = function($u, $p) { return false; };
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'username'  => 'foo',
-            'password'  => 'bar'
-        ));
-    }
-
-    function test_issueAccessToken_passwordGrant_passedInput()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = function($u, $p) { return 1; };
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $v = $a->issueAccessToken(array(
-            'grant_type'    =>  'password',
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'username'  => 'foo',
-            'password'  => 'bar'
-        ));
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
-    function test_issueAccessToken_passwordGrant()
-    {
-        $this->client->shouldReceive('getClient')->andReturn(array(
-            'client_id' =>  1234,
-            'client_secret' =>  5678,
-            'redirect_uri'  =>  'http://foo/redirect',
-            'name'  =>  'Example Client'
-        ));
-
-        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
-
-        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
-        $this->session->shouldReceive('createSession')->andReturn(1);
-        $this->session->shouldReceive('deleteSession')->andReturn(null);
-        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
-
-        $testCredentials = function($u, $p) { return 1; };
-
-        $a = $this->returnDefault();
-        $pgrant = new OAuth2\Grant\Password();
-        $pgrant->setVerifyCredentialsCallback($testCredentials);
-        $a->addGrantType($pgrant);
-
-        $_POST['grant_type'] = 'password';
-        $_POST['client_id'] = 1234;
-        $_POST['client_secret'] = 5678;
-        $_POST['username'] = 'foo';
-        $_POST['password'] = 'bar';
-
-        $request = new OAuth2\Util\Request(array(), $_POST);
-        $a->setRequest($request);
-
-        $v = $a->issueAccessToken();
-
-        $this->assertArrayHasKey('access_token', $v);
-        $this->assertArrayHasKey('token_type', $v);
-        $this->assertArrayHasKey('expires', $v);
-        $this->assertArrayHasKey('expires_in', $v);
-        $this->assertArrayHasKey('refresh_token', $v);
-
-        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
-        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
-    }
-
     public function tearDown() {
         M::close();
     }
diff --git a/tests/authentication/ClientCredentialsGrantTest.php b/tests/authentication/ClientCredentialsGrantTest.php
new file mode 100644
index 00000000..72e68919
--- /dev/null
+++ b/tests/authentication/ClientCredentialsGrantTest.php
@@ -0,0 +1,189 @@
+<?php
+
+use \Mockery as m;
+
+class Client_Credentials_Grant_Test extends PHPUnit_Framework_TestCase
+{
+    private $client;
+    private $session;
+    private $scope;
+
+    public function setUp()
+    {
+        $this->client = M::mock('OAuth2\Storage\ClientInterface');
+        $this->session = M::mock('OAuth2\Storage\SessionInterface');
+        $this->scope = M::mock('OAuth2\Storage\ScopeInterface');
+    }
+
+    private function returnDefault()
+    {
+        return new OAuth2\AuthServer($this->client, $this->session, $this->scope);
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_clientCredentialsGrant_missingClientId()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'client_credentials'
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_clientCredentialsGrant_missingClientPassword()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'client_credentials',
+            'client_id' =>  1234
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    8
+     */
+    public function test_issueAccessToken_clientCredentialsGrant_badClient()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(false);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'client_credentials',
+            'client_id' =>  1234,
+            'client_secret' =>  5678
+        ));
+    }
+
+    function test_issueAccessToken_clientCredentialsGrant_passedInput()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'client_credentials',
+            'client_id' =>  1234,
+            'client_secret' =>  5678
+        ));
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    function test_issueAccessToken_clientCredentialsGrant()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+
+        $_POST['grant_type'] = 'client_credentials';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    function test_issueAccessToken_clientCredentialsGrant_withRefreshToken()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\ClientCredentials());
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $_POST['grant_type'] = 'client_credentials';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+        $this->assertArrayHasKey('refresh_token', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+}
\ No newline at end of file
diff --git a/tests/authentication/PasswordGrantTest.php b/tests/authentication/PasswordGrantTest.php
new file mode 100644
index 00000000..ac6a7c83
--- /dev/null
+++ b/tests/authentication/PasswordGrantTest.php
@@ -0,0 +1,347 @@
+<?php
+
+use \Mockery as m;
+
+class Password_Grant_Test extends PHPUnit_Framework_TestCase
+{
+    private $client;
+    private $session;
+    private $scope;
+
+    public function setUp()
+    {
+        $this->client = M::mock('OAuth2\Storage\ClientInterface');
+        $this->session = M::mock('OAuth2\Storage\SessionInterface');
+        $this->scope = M::mock('OAuth2\Storage\ScopeInterface');
+    }
+
+    private function returnDefault()
+    {
+        return new OAuth2\AuthServer($this->client, $this->session, $this->scope);
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_passwordGrant_missingClientId()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\Password());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password'
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_passwordGrant_missingClientPassword()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\Password());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    8
+     */
+    public function test_issueAccessToken_passwordGrant_badClient()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(false);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\Password());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\InvalidGrantTypeException
+     */
+    function test_issueAccessToken_passwordGrant_invalidCallback()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = null;
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'username'  => 'foo',
+            'password'  => 'bar'
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    function test_issueAccessToken_passwordGrant_missingUsername()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return false; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    function test_issueAccessToken_passwordGrant_missingPassword()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return false; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'username'  =>  'foo'
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    function test_issueAccessToken_passwordGrant_badCredentials()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return false; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'username'  => 'foo',
+            'password'  => 'bar'
+        ));
+    }
+
+    function test_issueAccessToken_passwordGrant_passedInput()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return 1; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'password',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'username'  => 'foo',
+            'password'  => 'bar'
+        ));
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    function test_issueAccessToken_passwordGrant()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return 1; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+
+        $_POST['grant_type'] = 'password';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+        $_POST['username'] = 'foo';
+        $_POST['password'] = 'bar';
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    function test_issueAccessToken_passwordGrant_withRefreshToken()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('createSession')->andReturn(1);
+        $this->session->shouldReceive('deleteSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $testCredentials = function($u, $p) { return 1; };
+
+        $a = $this->returnDefault();
+        $pgrant = new OAuth2\Grant\Password();
+        $pgrant->setVerifyCredentialsCallback($testCredentials);
+        $a->addGrantType($pgrant);
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $_POST['grant_type'] = 'password';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+        $_POST['username'] = 'foo';
+        $_POST['password'] = 'bar';
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+        $this->assertArrayHasKey('refresh_token', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+}
\ No newline at end of file
diff --git a/tests/authentication/RefreshTokenTest.php b/tests/authentication/RefreshTokenTest.php
new file mode 100644
index 00000000..556477b3
--- /dev/null
+++ b/tests/authentication/RefreshTokenTest.php
@@ -0,0 +1,233 @@
+<?php
+
+use \Mockery as m;
+
+class Refresh_Token_test extends PHPUnit_Framework_TestCase
+{
+    private $client;
+    private $session;
+    private $scope;
+
+    public function setUp()
+    {
+        $this->client = M::mock('OAuth2\Storage\ClientInterface');
+        $this->session = M::mock('OAuth2\Storage\SessionInterface');
+        $this->scope = M::mock('OAuth2\Storage\ScopeInterface');
+    }
+
+    private function returnDefault()
+    {
+        return new OAuth2\AuthServer($this->client, $this->session, $this->scope);
+    }
+
+    public function test_issueAccessToken_with_refresh_token()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('updateSession')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\AuthCode());
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $_POST['grant_type'] = 'authorization_code';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+        $_POST['redirect_uri'] = 'http://foo/redirect';
+        $_POST['code'] = 'foobar';
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+        $this->assertArrayHasKey('refresh_token', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_refreshTokenGrant_missingClientId()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token'
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_refreshTokenGrant_missingClientSecret()
+    {
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token',
+            'client_id' =>  1234
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    8
+     */
+    public function test_issueAccessToken_refreshTokenGrant_badClient()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(false);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token',
+            'client_id' =>  1234,
+            'client_secret' =>  5678
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_refreshTokenGrant_missingRefreshToken()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array());
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            //'refresh_token' =>
+        ));
+    }
+
+    /**
+     * @expectedException        OAuth2\Exception\ClientException
+     * @expectedExceptionCode    0
+     */
+    public function test_issueAccessToken_refreshTokenGrant_badRefreshToken()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array());
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(false);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'refresh_token' =>  'abcdef'
+        ));
+    }
+
+    public function test_issueAccessToken_refreshTokenGrant_passedInput()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('updateSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $_POST['grant_type'] = 'refresh_token';
+        $_POST['client_id'] = 1234;
+        $_POST['client_secret'] = 5678;
+        $_POST['refresh_token'] = 'abcdef';
+
+        $request = new OAuth2\Util\Request(array(), $_POST);
+        $a->setRequest($request);
+
+        $v = $a->issueAccessToken();
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+        $this->assertArrayHasKey('refresh_token', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+
+    public function test_issueAccessToken_refreshTokenGrant()
+    {
+        $this->client->shouldReceive('getClient')->andReturn(array(
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'redirect_uri'  =>  'http://foo/redirect',
+            'name'  =>  'Example Client'
+        ));
+
+        $this->client->shouldReceive('validateRefreshToken')->andReturn(1);
+
+        $this->session->shouldReceive('validateAuthCode')->andReturn(1);
+        $this->session->shouldReceive('updateSession')->andReturn(null);
+        $this->session->shouldReceive('updateRefreshToken')->andReturn(null);
+
+        $a = $this->returnDefault();
+        $a->addGrantType(new OAuth2\Grant\RefreshToken());
+
+        $v = $a->issueAccessToken(array(
+            'grant_type'    =>  'refresh_token',
+            'client_id' =>  1234,
+            'client_secret' =>  5678,
+            'refresh_token'  =>  'abcdef',
+        ));
+
+        $this->assertArrayHasKey('access_token', $v);
+        $this->assertArrayHasKey('token_type', $v);
+        $this->assertArrayHasKey('expires', $v);
+        $this->assertArrayHasKey('expires_in', $v);
+        $this->assertArrayHasKey('refresh_token', $v);
+
+        $this->assertEquals($a::getExpiresIn(), $v['expires_in']);
+        $this->assertEquals(time()+$a::getExpiresIn(), $v['expires']);
+    }
+}
\ No newline at end of file