diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 000000000..fe13e48b8
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,74 @@
+name: Test Suite
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    services:
+      redis:
+        image: redis
+        ports:
+          - 6379:6379
+        options: --health-cmd="redis-cli ping" --health-interval=10s --health-timeout=5s --health-retries=3
+      mongodb:
+        image: mongo
+        ports:
+          - 27017:27017
+      myriadb:
+        image: mariadb
+        env:
+          MYSQL_ROOT_PASSWORD: root
+        ports:
+          - 3808:3808
+          - 3306:3306
+      postgres:
+        image: postgres
+        env:
+          POSTGRES_DB: oauth2_server_php
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+        ports:
+          - 5432:5432
+        options: --health-cmd="pg_isready -h localhost" --health-interval=10s --health-timeout=5s --health-retries=5
+    strategy:
+      matrix:
+        php: [ 7.2, 7.3, 7.4, "8.0", 8.1, 8.2 ]
+    name: "PHP ${{ matrix.php }} Unit Test"
+    steps:
+      - uses: actions/checkout@v2
+      - uses: codecov/codecov-action@v1
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          extensions: mongodb, mbstring, intl, redis, pdo_mysql
+      - name: Install composer dependencies
+        uses: nick-invision/retry@v1
+        with:
+          timeout_minutes: 10
+          max_attempts: 3
+          command: composer install
+      - name: Run PHPUnit
+        run: vendor/bin/phpunit -v
+  phpstan:
+    name: "PHPStan"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.1
+      - name: Install composer dependencies
+        uses: nick-invision/retry@v1
+        with:
+          timeout_minutes: 10
+          max_attempts: 3
+          command: composer install
+      - name: Run PHPStan
+        run: |
+          composer require phpstan/phpstan
+          vendor/bin/phpstan analyse --level=0 src/
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 5f4b9f5e2..000000000
--- a/.travis.yml
+++ /dev/null
@@ -1,35 +0,0 @@
-language: php
-sudo: false
-dist: precise
-cache:
-  directories:
-    - $HOME/.composer/cache
-    - vendor
-php:
-- 5.3
-- 5.4
-- 5.5
-- 5.6
-- 7.0
-- 7.1
-- 7.2
-env:
-  global:
-  - secure: Bc5ZqvZ1YYpoPZNNuU2eCB8DS6vBYrAdfBtTenBs5NSxzb+Vjven4kWakbzaMvZjb/Ib7Uph7DGuOtJXpmxnvBXPLd707LZ89oFWN/yqQlZKCcm8iErvJCB5XL+/ONHj2iPdR242HJweMcat6bMCwbVWoNDidjtWMH0U2mYFy3M=
-  - secure: R3bXlymyFiY2k2jf7+fv/J8i34wtXTkmD4mCr5Ps/U+vn9axm2VtvR2Nj+r7LbRjn61gzFE/xIVjYft/wOyBOYwysrfriydrnRVS0owh6y+7EyOyQWbRX11vVQMf8o31QCQE5BY58V5AJZW3MjoOL0FVlTgySJiJvdw6Pv18v+E=
-services:
-- mongodb
-- redis-server
-- cassandra
-before_install:
-- phpenv config-rm xdebug.ini || return 0
-- phpenv version-name | grep ^5.[3-6] && composer remove mongodb/mongodb --dev && echo "extension=mongo.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini ; true
-- phpenv version-name | grep ^7 && pecl install -f mongodb-1.3.4 ; true
-install:
-- composer install
-before_script:
-- psql -c 'create database oauth2_server_php;' -U postgres
-after_script:
-- php test/cleanup.php
-script:
-- vendor/bin/phpunit -v
diff --git a/README.md b/README.md
index 117743d4f..4ecadbe7a 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,6 @@
 oauth2-server-php
 =================
 
-[![Build Status](https://travis-ci.org/bshaffer/oauth2-server-php.svg?branch=master)](https://travis-ci.org/bshaffer/oauth2-server-php)
-
-[![Total Downloads](https://poser.pugx.org/bshaffer/oauth2-server-php/downloads.png)](https://packagist.org/packages/bshaffer/oauth2-server-php)
+[![Total Downloads](https://poser.pugx.org/bshaffer/oauth2-server-php/downloads)](https://packagist.org/packages/bshaffer/oauth2-server-php)
 
 View the [complete documentation](https://bshaffer.github.io/oauth2-server-php-docs/)
diff --git a/composer.json b/composer.json
index 272d20027..50a950774 100644
--- a/composer.json
+++ b/composer.json
@@ -16,21 +16,21 @@
         "psr-0": { "OAuth2": "src/" }
     },
     "require":{
-        "php":">=5.3.9"
+        "php":">=7.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.0",
-        "aws/aws-sdk-php": "~2.8",
-        "firebase/php-jwt": "~2.2",
-        "predis/predis": "dev-master",
+        "phpunit/phpunit": "^7.5||^8.0",
+        "aws/aws-sdk-php": "^2.8",
+        "firebase/php-jwt": "^6.4",
+        "predis/predis": "^1.1",
         "thobbs/phpcassa": "dev-master",
-        "mongodb/mongodb": "^1.1"
+        "yoast/phpunit-polyfills": "^1.0"
     },
     "suggest": {
         "predis/predis": "Required to use Redis storage",
         "thobbs/phpcassa": "Required to use Cassandra storage",
         "aws/aws-sdk-php": "~2.8 is required to use DynamoDB storage",
-        "firebase/php-jwt": "~2.2 is required to use JWT features",
+        "firebase/php-jwt": "~v6.4 is required to use JWT features",
         "mongodb/mongodb": "^1.1 is required to use MongoDB storage"
     }
 }
diff --git a/phpunit.xml b/phpunit.xml
index e36403f0a..6e663e39d 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -8,7 +8,6 @@
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
          bootstrap="test/bootstrap.php"
 >
   <testsuites>
diff --git a/src/OAuth2/Autoloader.php b/src/OAuth2/Autoloader.php
index 4ec08cbdd..b025db34c 100644
--- a/src/OAuth2/Autoloader.php
+++ b/src/OAuth2/Autoloader.php
@@ -39,7 +39,7 @@ public static function register($dir = null)
      * Handles autoloading of classes.
      *
      * @param string $class - A class name.
-     * @return boolean      - Returns true if the class has been loaded
+     * @return void
      */
     public function autoload($class)
     {
diff --git a/src/OAuth2/ClientAssertionType/HttpBasic.php b/src/OAuth2/ClientAssertionType/HttpBasic.php
index ef6120300..0d8007178 100644
--- a/src/OAuth2/ClientAssertionType/HttpBasic.php
+++ b/src/OAuth2/ClientAssertionType/HttpBasic.php
@@ -112,7 +112,7 @@ public function getClientId()
      *
      * @ingroup oauth2_section_2
      */
-    public function getClientCredentials(RequestInterface $request, ResponseInterface $response = null)
+    public function getClientCredentials(RequestInterface $request, ?ResponseInterface $response = null)
     {
         if (!is_null($request->headers('PHP_AUTH_USER')) && !is_null($request->headers('PHP_AUTH_PW'))) {
             return array('client_id' => $request->headers('PHP_AUTH_USER'), 'client_secret' => $request->headers('PHP_AUTH_PW'));
diff --git a/src/OAuth2/Controller/AuthorizeController.php b/src/OAuth2/Controller/AuthorizeController.php
index 4bafb1d24..181f884a6 100644
--- a/src/OAuth2/Controller/AuthorizeController.php
+++ b/src/OAuth2/Controller/AuthorizeController.php
@@ -78,7 +78,7 @@ class AuthorizeController implements AuthorizeControllerInterface
      *     );
      * @endcode
      */
-    public function __construct(ClientInterface $clientStorage, array $responseTypes = array(), array $config = array(), ScopeInterface $scopeUtil = null)
+    public function __construct(ClientInterface $clientStorage, array $responseTypes = array(), array $config = array(), ?ScopeInterface $scopeUtil = null)
     {
         $this->clientStorage = $clientStorage;
         $this->responseTypes = $responseTypes;
@@ -87,6 +87,7 @@ public function __construct(ClientInterface $clientStorage, array $responseTypes
             'enforce_state'  => true,
             'require_exact_redirect_uri' => true,
             'redirect_status_code' => 302,
+            'enforce_pkce' => false,
         ), $config);
 
         if (is_null($scopeUtil)) {
diff --git a/src/OAuth2/Controller/ResourceController.php b/src/OAuth2/Controller/ResourceController.php
index 926f90fda..2a5d4b4e3 100644
--- a/src/OAuth2/Controller/ResourceController.php
+++ b/src/OAuth2/Controller/ResourceController.php
@@ -47,7 +47,7 @@ class ResourceController implements ResourceControllerInterface
      * @param array                $config
      * @param ScopeInterface       $scopeUtil
      */
-    public function __construct(TokenTypeInterface $tokenType, AccessTokenInterface $tokenStorage, $config = array(), ScopeInterface $scopeUtil = null)
+    public function __construct(TokenTypeInterface $tokenType, AccessTokenInterface $tokenStorage, $config = array(), ?ScopeInterface $scopeUtil = null)
     {
         $this->tokenType = $tokenType;
         $this->tokenStorage = $tokenStorage;
diff --git a/src/OAuth2/Controller/TokenController.php b/src/OAuth2/Controller/TokenController.php
index 7fdaf85a6..1e21b5f67 100644
--- a/src/OAuth2/Controller/TokenController.php
+++ b/src/OAuth2/Controller/TokenController.php
@@ -54,7 +54,7 @@ class TokenController implements TokenControllerInterface
      * @param ScopeInterface               $scopeUtil
      * @throws InvalidArgumentException
      */
-    public function __construct(AccessTokenInterface $accessToken, ClientInterface $clientStorage, array $grantTypes = array(), ClientAssertionTypeInterface $clientAssertionType = null, ScopeInterface $scopeUtil = null)
+    public function __construct(AccessTokenInterface $accessToken, ClientInterface $clientStorage, array $grantTypes = array(), ?ClientAssertionTypeInterface $clientAssertionType = null, ?ScopeInterface $scopeUtil = null)
     {
         if (is_null($clientAssertionType)) {
             foreach ($grantTypes as $grantType) {
diff --git a/src/OAuth2/Encryption/FirebaseJwt.php b/src/OAuth2/Encryption/FirebaseJwt.php
index 1b527e0a0..8524bb32c 100644
--- a/src/OAuth2/Encryption/FirebaseJwt.php
+++ b/src/OAuth2/Encryption/FirebaseJwt.php
@@ -2,6 +2,9 @@
 
 namespace OAuth2\Encryption;
 
+use Firebase\JWT\JWT;
+use Firebase\JWT\Key;
+
 /**
  * Bridge file to use the firebase/php-jwt package for JWT encoding and decoding.
  * @author Francis Chuang <francis.chuang@gmail.com>
@@ -10,26 +13,36 @@ class FirebaseJwt implements EncryptionInterface
 {
     public function __construct()
     {
-        if (!class_exists('\JWT')) {
+        if (!class_exists(JWT::class)) {
             throw new \ErrorException('firebase/php-jwt must be installed to use this feature. You can do this by running "composer require firebase/php-jwt"');
         }
     }
 
     public function encode($payload, $key, $alg = 'HS256', $keyId = null)
     {
-        return \JWT::encode($payload, $key, $alg, $keyId);
+        return JWT::encode($payload, $key, $alg, $keyId);
     }
 
     public function decode($jwt, $key = null, $allowedAlgorithms = null)
     {
         try {
-
             //Maintain BC: Do not verify if no algorithms are passed in.
             if (!$allowedAlgorithms) {
-                $key = null;
+                $tks = \explode('.', $jwt);
+                if (\count($tks) === 3) {
+                    [$headb64] = $tks;
+                    $headerRaw = JWT::urlsafeB64Decode($headb64);
+                    if (($header = JWT::jsonDecode($headerRaw))) {
+                        $key = new Key($key, $header->alg);
+                    }
+                }
+            } elseif(is_array($allowedAlgorithms)) {
+                $key = new Key($key, $allowedAlgorithms[0]);
+            } else {
+                $key = new Key($key, $allowedAlgorithms);
             }
 
-            return (array)\JWT::decode($jwt, $key, $allowedAlgorithms);
+            return (array) JWT::decode($jwt, $key);
         } catch (\Exception $e) {
             return false;
         }
@@ -37,11 +50,11 @@ public function decode($jwt, $key = null, $allowedAlgorithms = null)
 
     public function urlSafeB64Encode($data)
     {
-        return \JWT::urlsafeB64Encode($data);
+        return JWT::urlsafeB64Encode($data);
     }
 
     public function urlSafeB64Decode($b64)
     {
-        return \JWT::urlsafeB64Decode($b64);
+        return JWT::urlsafeB64Decode($b64);
     }
 }
diff --git a/src/OAuth2/GrantType/AuthorizationCode.php b/src/OAuth2/GrantType/AuthorizationCode.php
index 784f6b3a3..5bcb4f253 100644
--- a/src/OAuth2/GrantType/AuthorizationCode.php
+++ b/src/OAuth2/GrantType/AuthorizationCode.php
@@ -84,6 +84,41 @@ public function validateRequest(RequestInterface $request, ResponseInterface $re
             return false;
         }
 
+        if (isset($authCode['code_challenge']) && $authCode['code_challenge']) {
+            if (!($code_verifier = $request->request('code_verifier'))) {
+                $response->setError(400, 'code_verifier_missing', "The PKCE code verifier parameter is required.");
+
+                return false;
+            }
+            // Validate code_verifier according to RFC-7636
+            // @see: https://tools.ietf.org/html/rfc7636#section-4.1
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $code_verifier) !== 1) {
+                $response->setError(400, 'code_verifier_invalid', "The PKCE code verifier parameter is invalid.");
+
+                return false;
+            }
+            $code_verifier = $request->request('code_verifier');
+            switch ($authCode['code_challenge_method']) {
+                case 'S256':
+                    $code_verifier_hashed = strtr(rtrim(base64_encode(hash('sha256', $code_verifier, true)), '='), '+/', '-_');
+                    break;
+
+                case 'plain':
+                    $code_verifier_hashed = $code_verifier;
+                    break;
+
+                default:
+                    $response->setError(400, 'code_challenge_method_invalid', "Unknown PKCE code challenge method.");
+
+                return FALSE;
+            }
+            if ($code_verifier_hashed !== $authCode['code_challenge']) {
+                $response->setError(400, 'code_verifier_mismatch', "The PKCE code verifier parameter does not match the code challenge.");
+
+                return FALSE;
+            }
+        }
+
         if (!isset($authCode['code'])) {
             $authCode['code'] = $code; // used to expire the code after the access token is granted
         }
diff --git a/src/OAuth2/GrantType/JwtBearer.php b/src/OAuth2/GrantType/JwtBearer.php
index 62c1efabd..6d5a9f963 100644
--- a/src/OAuth2/GrantType/JwtBearer.php
+++ b/src/OAuth2/GrantType/JwtBearer.php
@@ -37,7 +37,7 @@ class JwtBearer implements GrantTypeInterface, ClientAssertionTypeInterface
      * @param EncryptionInterface|JWT $jwtUtil  - OPTONAL The class used to decode, encode and verify JWTs.
      * @param array                   $config
      */
-    public function __construct(JwtBearerInterface $storage, $audience, EncryptionInterface $jwtUtil = null, array $config = array())
+    public function __construct(JwtBearerInterface $storage, $audience, ?EncryptionInterface $jwtUtil = null, array $config = array())
     {
         $this->storage = $storage;
         $this->audience = $audience;
@@ -46,13 +46,13 @@ public function __construct(JwtBearerInterface $storage, $audience, EncryptionIn
             $jwtUtil = new Jwt();
         }
 
-        $this->config = array_merge(array(
+        $config = array_merge(array(
             'allowed_algorithms' => array('RS256', 'RS384', 'RS512')
         ), $config);
 
         $this->jwtUtil = $jwtUtil;
 
-        $this->allowedAlgorithms = $this->config['allowed_algorithms'];
+        $this->allowedAlgorithms = $config['allowed_algorithms'];
     }
 
     /**
@@ -127,7 +127,7 @@ public function validateRequest(RequestInterface $request, ResponseInterface $re
         }
 
         // Check expiration
-        if (ctype_digit($jwt['exp'])) {
+        if (ctype_digit((string)$jwt['exp'])) {
             if ($jwt['exp'] <= time()) {
                 $response->setError(400, 'invalid_grant', "JWT has expired");
 
@@ -141,7 +141,7 @@ public function validateRequest(RequestInterface $request, ResponseInterface $re
 
         // Check the not before time
         if ($notBefore = $jwt['nbf']) {
-            if (ctype_digit($notBefore)) {
+            if (ctype_digit((string)$notBefore)) {
                 if ($notBefore > time()) {
                     $response->setError(400, 'invalid_grant', "JWT cannot be used before the Not Before (nbf) time");
 
diff --git a/src/OAuth2/OpenID/Controller/AuthorizeController.php b/src/OAuth2/OpenID/Controller/AuthorizeController.php
index 54c5f9a63..52e183bb3 100644
--- a/src/OAuth2/OpenID/Controller/AuthorizeController.php
+++ b/src/OAuth2/OpenID/Controller/AuthorizeController.php
@@ -16,6 +16,16 @@ class AuthorizeController extends BaseAuthorizeController implements AuthorizeCo
      */
     private $nonce;
 
+    /**
+     * @var mixed
+     */
+    protected $code_challenge;
+
+    /**
+     * @var mixed
+     */
+    protected $code_challenge_method;
+
     /**
      * Set not authorized response
      *
@@ -65,6 +75,10 @@ protected function buildAuthorizeParameters($request, $response, $user_id)
         // add the nonce to return with the redirect URI
         $params['nonce'] = $this->nonce;
 
+        // Add PKCE code challenge.
+        $params['code_challenge'] = $this->code_challenge;
+        $params['code_challenge_method'] = $this->code_challenge_method;
+
         return $params;
     }
 
@@ -90,6 +104,32 @@ public function validateAuthorizeRequest(RequestInterface $request, ResponseInte
 
         $this->nonce = $nonce;
 
+        $code_challenge = $request->query('code_challenge');
+        $code_challenge_method = $request->query('code_challenge_method');
+
+        if ($this->config['enforce_pkce']) {
+            if (!$code_challenge) {
+                $response->setError(400, 'missing_code_challenge', 'This application requires you provide a PKCE code challenge');
+
+                return false;
+            }
+
+            if (preg_match('/^[A-Za-z0-9-._~]{43,128}$/', $code_challenge) !== 1) {
+            $response->setError(400, 'invalid_code_challenge', 'The PKCE code challenge supplied is invalid');
+
+            return false;
+          }
+
+            if (!in_array($code_challenge_method, array('plain', 'S256'), true)) {
+                $response->setError(400, 'missing_code_challenge_method', 'This application requires you specify a PKCE code challenge method');
+
+                return false;
+            }
+        }
+
+        $this->code_challenge = $code_challenge;
+        $this->code_challenge_method = $code_challenge_method;
+
         return true;
     }
 
diff --git a/src/OAuth2/OpenID/Controller/UserInfoController.php b/src/OAuth2/OpenID/Controller/UserInfoController.php
index c489b7af3..e6f8fd77b 100644
--- a/src/OAuth2/OpenID/Controller/UserInfoController.php
+++ b/src/OAuth2/OpenID/Controller/UserInfoController.php
@@ -30,7 +30,7 @@ class UserInfoController extends ResourceController implements UserInfoControlle
      * @param array                $config
      * @param ScopeInterface       $scopeUtil
      */
-    public function __construct(TokenTypeInterface $tokenType, AccessTokenInterface $tokenStorage, UserClaimsInterface $userClaimsStorage, $config = array(), ScopeInterface $scopeUtil = null)
+    public function __construct(TokenTypeInterface $tokenType, AccessTokenInterface $tokenStorage, UserClaimsInterface $userClaimsStorage, $config = array(), ?ScopeInterface $scopeUtil = null)
     {
         parent::__construct($tokenType, $tokenStorage, $config, $scopeUtil);
 
diff --git a/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php b/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
index b8ad41ffb..19e04104d 100644
--- a/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
+++ b/src/OAuth2/OpenID/ResponseType/AuthorizationCode.php
@@ -31,9 +31,9 @@ public function getAuthorizeResponse($params, $user_id = null)
         // build the URL to redirect to
         $result = array('query' => array());
 
-        $params += array('scope' => null, 'state' => null, 'id_token' => null);
+        $params += array('scope' => null, 'state' => null, 'id_token' => null, 'code_challenge' => null, 'code_challenge_method' => null);
 
-        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['id_token']);
+        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['id_token'], $params['code_challenge'], $params['code_challenge_method']);
 
         if (isset($params['state'])) {
             $result['query']['state'] = $params['state'];
@@ -56,10 +56,10 @@ public function getAuthorizeResponse($params, $user_id = null)
      * @see http://tools.ietf.org/html/rfc6749#section-4
      * @ingroup oauth2_section_4
      */
-    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $id_token = null)
+    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         $code = $this->generateAuthorizationCode();
-        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, $id_token);
+        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, $id_token, $code_challenge, $code_challenge_method);
 
         return $code;
     }
diff --git a/src/OAuth2/OpenID/ResponseType/IdToken.php b/src/OAuth2/OpenID/ResponseType/IdToken.php
index 55e446074..98973f9e9 100644
--- a/src/OAuth2/OpenID/ResponseType/IdToken.php
+++ b/src/OAuth2/OpenID/ResponseType/IdToken.php
@@ -38,7 +38,7 @@ class IdToken implements IdTokenInterface
      * @param EncryptionInterface $encryptionUtil
      * @throws LogicException
      */
-    public function __construct(UserClaimsInterface $userClaimsStorage, PublicKeyInterface $publicKeyStorage, array $config = array(), EncryptionInterface $encryptionUtil = null)
+    public function __construct(UserClaimsInterface $userClaimsStorage, PublicKeyInterface $publicKeyStorage, array $config = array(), ?EncryptionInterface $encryptionUtil = null)
     {
         $this->userClaimsStorage = $userClaimsStorage;
         $this->publicKeyStorage = $publicKeyStorage;
diff --git a/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php b/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
index 446cec928..8e0988ff4 100644
--- a/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
+++ b/src/OAuth2/OpenID/Storage/AuthorizationCodeInterface.php
@@ -33,5 +33,5 @@ interface AuthorizationCodeInterface extends BaseAuthorizationCodeInterface
      *
      * @ingroup oauth2_section_4
      */
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null);
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null);
 }
diff --git a/src/OAuth2/Request.php b/src/OAuth2/Request.php
index f547bf6e8..56a681a62 100644
--- a/src/OAuth2/Request.php
+++ b/src/OAuth2/Request.php
@@ -34,7 +34,7 @@ class Request implements RequestInterface
      *
      * @api
      */
-    public function __construct(array $query = array(), array $request = array(), array $attributes = array(), array $cookies = array(), array $files = array(), array $server = array(), $content = null, array $headers = null)
+    public function __construct(array $query = array(), array $request = array(), array $attributes = array(), array $cookies = array(), array $files = array(), array $server = array(), $content = null, ?array $headers = null)
     {
         $this->initialize($query, $request, $attributes, $cookies, $files, $server, $content, $headers);
     }
@@ -55,7 +55,7 @@ public function __construct(array $query = array(), array $request = array(), ar
      *
      * @api
      */
-    public function initialize(array $query = array(), array $request = array(), array $attributes = array(), array $cookies = array(), array $files = array(), array $server = array(), $content = null, array $headers = null)
+    public function initialize(array $query = array(), array $request = array(), array $attributes = array(), array $cookies = array(), array $files = array(), array $server = array(), $content = null, ?array $headers = null)
     {
         $this->request = $request;
         $this->query = $query;
diff --git a/src/OAuth2/Response.php b/src/OAuth2/Response.php
index 88c1ad5f7..be1eaa2ac 100644
--- a/src/OAuth2/Response.php
+++ b/src/OAuth2/Response.php
@@ -140,11 +140,10 @@ public function getStatusCode()
     }
 
     /**
-     * @param int $statusCode
      * @param string $text
      * @throws InvalidArgumentException
      */
-    public function setStatusCode($statusCode, $text = null)
+    public function setStatusCode(int $statusCode, $text = null)
     {
         $this->statusCode = (int) $statusCode;
         if ($this->isInvalid()) {
diff --git a/src/OAuth2/ResponseInterface.php b/src/OAuth2/ResponseInterface.php
index fe920864a..df4fa48f5 100644
--- a/src/OAuth2/ResponseInterface.php
+++ b/src/OAuth2/ResponseInterface.php
@@ -20,10 +20,7 @@ public function addParameters(array $parameters);
      */
     public function addHttpHeaders(array $httpHeaders);
 
-    /**
-     * @param int $statusCode
-     */
-    public function setStatusCode($statusCode);
+    public function setStatusCode(int $statusCode);
 
     /**
      * @param int    $statusCode
diff --git a/src/OAuth2/ResponseType/AccessToken.php b/src/OAuth2/ResponseType/AccessToken.php
index e836a3447..8b5aec14a 100644
--- a/src/OAuth2/ResponseType/AccessToken.php
+++ b/src/OAuth2/ResponseType/AccessToken.php
@@ -38,7 +38,7 @@ class AccessToken implements AccessTokenInterface
      *     );
      * @endcode
      */
-    public function __construct(AccessTokenStorageInterface $tokenStorage, RefreshTokenInterface $refreshStorage = null, array $config = array())
+    public function __construct(AccessTokenStorageInterface $tokenStorage, ?RefreshTokenInterface $refreshStorage = null, array $config = array())
     {
         $this->tokenStorage = $tokenStorage;
         $this->refreshStorage = $refreshStorage;
diff --git a/src/OAuth2/ResponseType/AuthorizationCode.php b/src/OAuth2/ResponseType/AuthorizationCode.php
index b92c73cda..12a9f8c38 100644
--- a/src/OAuth2/ResponseType/AuthorizationCode.php
+++ b/src/OAuth2/ResponseType/AuthorizationCode.php
@@ -26,9 +26,9 @@ public function getAuthorizeResponse($params, $user_id = null)
         // build the URL to redirect to
         $result = array('query' => array());
 
-        $params += array('scope' => null, 'state' => null);
+        $params += array('scope' => null, 'state' => null, 'code_challenge' => null, 'code_challenge_method' => null);
 
-        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope']);
+        $result['query']['code'] = $this->createAuthorizationCode($params['client_id'], $user_id, $params['redirect_uri'], $params['scope'], $params['code_challenge'], $params['code_challenge_method']);
 
         if (isset($params['state'])) {
             $result['query']['state'] = $params['state'];
@@ -53,10 +53,10 @@ public function getAuthorizeResponse($params, $user_id = null)
      * @see http://tools.ietf.org/html/rfc6749#section-4
      * @ingroup oauth2_section_4
      */
-    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null)
+    public function createAuthorizationCode($client_id, $user_id, $redirect_uri, $scope = null, $code_challenge = null, $code_challenge_method = null)
     {
         $code = $this->generateAuthorizationCode();
-        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope);
+        $this->storage->setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, time() + $this->config['auth_code_lifetime'], $scope, null, $code_challenge, $code_challenge_method);
 
         return $code;
     }
diff --git a/src/OAuth2/ResponseType/JwtAccessToken.php b/src/OAuth2/ResponseType/JwtAccessToken.php
index 0ee3708aa..13a24a56d 100644
--- a/src/OAuth2/ResponseType/JwtAccessToken.php
+++ b/src/OAuth2/ResponseType/JwtAccessToken.php
@@ -26,7 +26,7 @@ class JwtAccessToken extends AccessToken
      *                                                        or just the token ID is stored
      * @param EncryptionInterface         $encryptionUtil   -
      */
-    public function __construct(PublicKeyInterface $publicKeyStorage = null, AccessTokenStorageInterface $tokenStorage = null, RefreshTokenInterface $refreshStorage = null, array $config = array(), EncryptionInterface $encryptionUtil = null)
+    public function __construct(?PublicKeyInterface $publicKeyStorage = null, ?AccessTokenStorageInterface $tokenStorage = null, ?RefreshTokenInterface $refreshStorage = null, array $config = array(), ?EncryptionInterface $encryptionUtil = null)
     {
         $this->publicKeyStorage = $publicKeyStorage;
         $config = array_merge(array(
diff --git a/src/OAuth2/Server.php b/src/OAuth2/Server.php
index cf040c2bc..e5716358d 100644
--- a/src/OAuth2/Server.php
+++ b/src/OAuth2/Server.php
@@ -150,7 +150,7 @@ class Server implements ResourceControllerInterface,
      *
      * @ingroup oauth2_section_7
      */
-    public function __construct($storage = array(), array $config = array(), array $grantTypes = array(), array $responseTypes = array(), TokenTypeInterface $tokenType = null, ScopeInterface $scopeUtil = null, ClientAssertionTypeInterface $clientAssertionType = null)
+    public function __construct($storage = array(), array $config = array(), array $grantTypes = array(), array $responseTypes = array(), ?TokenTypeInterface $tokenType = null, ?ScopeInterface $scopeUtil = null, ?ClientAssertionTypeInterface $clientAssertionType = null)
     {
         $storage = is_array($storage) ? $storage : array($storage);
         $this->storages = array();
@@ -172,6 +172,7 @@ public function __construct($storage = array(), array $config = array(), array $
             'enforce_state'            => true,
             'require_exact_redirect_uri' => true,
             'allow_implicit'           => false,
+            'enforce_pkce'             => false,
             'allow_credentials_in_request_body' => true,
             'allow_public_clients'     => true,
             'always_issue_new_refresh_token' => false,
@@ -288,7 +289,7 @@ public function setUserInfoController(UserInfoControllerInterface $userInfoContr
      *
      * @see http://openid.net/specs/openid-connect-core-1_0.html#UserInfo
      */
-    public function handleUserInfoRequest(RequestInterface $request, ResponseInterface $response = null)
+    public function handleUserInfoRequest(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $this->getUserInfoController()->handleUserInfoRequest($request, $this->response);
@@ -314,7 +315,7 @@ public function handleUserInfoRequest(RequestInterface $request, ResponseInterfa
      *
      * @ingroup oauth2_section_4
      */
-    public function handleTokenRequest(RequestInterface $request, ResponseInterface $response = null)
+    public function handleTokenRequest(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $this->getTokenController()->handleTokenRequest($request, $this->response);
@@ -327,7 +328,7 @@ public function handleTokenRequest(RequestInterface $request, ResponseInterface
      * @param ResponseInterface $response - Response object
      * @return mixed
      */
-    public function grantAccessToken(RequestInterface $request, ResponseInterface $response = null)
+    public function grantAccessToken(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $value = $this->getTokenController()->grantAccessToken($request, $this->response);
@@ -345,7 +346,7 @@ public function grantAccessToken(RequestInterface $request, ResponseInterface $r
      * @param ResponseInterface $response
      * @return Response|ResponseInterface
      */
-    public function handleRevokeRequest(RequestInterface $request, ResponseInterface $response = null)
+    public function handleRevokeRequest(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $this->getTokenController()->handleRevokeRequest($request, $this->response);
@@ -407,7 +408,7 @@ public function handleAuthorizeRequest(RequestInterface $request, ResponseInterf
      *
      * @ingroup oauth2_section_3
      */
-    public function validateAuthorizeRequest(RequestInterface $request, ResponseInterface $response = null)
+    public function validateAuthorizeRequest(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $value = $this->getAuthorizeController()->validateAuthorizeRequest($request, $this->response);
@@ -421,7 +422,7 @@ public function validateAuthorizeRequest(RequestInterface $request, ResponseInte
      * @param string            $scope    - Scope
      * @return mixed
      */
-    public function verifyResourceRequest(RequestInterface $request, ResponseInterface $response = null, $scope = null)
+    public function verifyResourceRequest(RequestInterface $request, ?ResponseInterface $response = null, $scope = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $value = $this->getResourceController()->verifyResourceRequest($request, $this->response, $scope);
@@ -434,7 +435,7 @@ public function verifyResourceRequest(RequestInterface $request, ResponseInterfa
      * @param ResponseInterface $response - Response object
      * @return mixed
      */
-    public function getAccessTokenData(RequestInterface $request, ResponseInterface $response = null)
+    public function getAccessTokenData(RequestInterface $request, ?ResponseInterface $response = null)
     {
         $this->response = is_null($response) ? new Response() : $response;
         $value = $this->getResourceController()->getAccessTokenData($request, $this->response);
@@ -577,7 +578,7 @@ protected function createDefaultAuthorizeController()
             }
         }
 
-        $config = array_intersect_key($this->config, array_flip(explode(' ', 'allow_implicit enforce_state require_exact_redirect_uri')));
+        $config = array_intersect_key($this->config, array_flip(explode(' ', 'allow_implicit enforce_state require_exact_redirect_uri enforce_pkce')));
 
         if ($this->config['use_openid_connect']) {
             return new OpenIDAuthorizeController($this->storages['client'], $this->responseTypes, $config, $this->getScopeUtil());
diff --git a/src/OAuth2/Storage/Cassandra.php b/src/OAuth2/Storage/Cassandra.php
index e60e9d3ad..3a138bb52 100644
--- a/src/OAuth2/Storage/Cassandra.php
+++ b/src/OAuth2/Storage/Cassandra.php
@@ -191,11 +191,11 @@ public function getAuthorizationCode($code)
      * @param string $id_token
      * @return bool
      */
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         return $this->setValue(
             $this->config['code_key'] . $authorization_code,
-            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'),
+            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'),
             $expires
         );
     }
diff --git a/src/OAuth2/Storage/CouchbaseDB.php b/src/OAuth2/Storage/CouchbaseDB.php
index 9e8148b6b..31b0cd301 100755
--- a/src/OAuth2/Storage/CouchbaseDB.php
+++ b/src/OAuth2/Storage/CouchbaseDB.php
@@ -2,6 +2,7 @@
 
 namespace OAuth2\Storage;
 
+use Couchbase;
 use OAuth2\OpenID\Storage\AuthorizationCodeInterface as OpenIDAuthorizationCodeInterface;
 
 /**
@@ -27,14 +28,18 @@ class CouchbaseDB implements AuthorizationCodeInterface,
 
     public function __construct($connection, $config = array())
     {
-        if ($connection instanceof \Couchbase) {
+        if (!class_exists(Couchbase::class)) {
+            throw new \RuntimeException('Missing Couchbase');
+        }
+
+        if ($connection instanceof Couchbase) {
             $this->db = $connection;
         } else {
             if (!is_array($connection) || !is_array($connection['servers'])) {
                 throw new \InvalidArgumentException('First argument to OAuth2\Storage\CouchbaseDB must be an instance of Couchbase or a configuration array containing a server array');
             }
 
-            $this->db = new \Couchbase($connection['servers'], (!isset($connection['username'])) ? '' : $connection['username'], (!isset($connection['password'])) ? '' : $connection['password'], $connection['bucket'], false);
+            $this->db = new Couchbase($connection['servers'], (!isset($connection['username'])) ? '' : $connection['username'], (!isset($connection['password'])) ? '' : $connection['password'], $connection['bucket'], false);
         }
 
         $this->config = array_merge(array(
@@ -173,7 +178,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -185,6 +190,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             ));
         } else {
             $this->setObjectByType('code_table',$code,array(
@@ -195,6 +202,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             ));
         }
 
@@ -328,4 +337,4 @@ public function setJti($client_id, $subject, $audience, $expiration, $jti)
         //TODO: Needs couchbase implementation.
         throw new \Exception('setJti() for the Couchbase driver is currently unimplemented.');
     }
-}
\ No newline at end of file
+}
diff --git a/src/OAuth2/Storage/DynamoDB.php b/src/OAuth2/Storage/DynamoDB.php
index a54cb3712..713189d23 100644
--- a/src/OAuth2/Storage/DynamoDB.php
+++ b/src/OAuth2/Storage/DynamoDB.php
@@ -213,12 +213,12 @@ public function getAuthorizationCode($code)
 
     }
 
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // convert expires to datestring
         $expires = date('Y-m-d H:i:s', $expires);
 
-        $clientData = compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'id_token', 'scope');
+        $clientData = compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method');
         $clientData = array_filter($clientData, 'self::isNotEmpty');
 
         $result = $this->client->putItem(array(
diff --git a/src/OAuth2/Storage/JwtAccessToken.php b/src/OAuth2/Storage/JwtAccessToken.php
index 6ccacd6d9..73c5a3e62 100644
--- a/src/OAuth2/Storage/JwtAccessToken.php
+++ b/src/OAuth2/Storage/JwtAccessToken.php
@@ -21,7 +21,7 @@ class JwtAccessToken implements JwtAccessTokenInterface
      *                                                                is not necessary when using this grant type.
      * @param OAuth2\Encryption\EncryptionInterface $encryptionUtil   OPTIONAL class to use for "encode" and "decode" functions.
      */
-    public function __construct(PublicKeyInterface $publicKeyStorage, AccessTokenInterface $tokenStorage = null, EncryptionInterface $encryptionUtil = null)
+    public function __construct(PublicKeyInterface $publicKeyStorage, ?AccessTokenInterface $tokenStorage = null, ?EncryptionInterface $encryptionUtil = null)
     {
         $this->publicKeyStorage = $publicKeyStorage;
         $this->tokenStorage = $tokenStorage;
@@ -84,4 +84,4 @@ protected function convertJwtToOAuth2($tokenData)
 
         return $tokenData;
     }
-}
\ No newline at end of file
+}
diff --git a/src/OAuth2/Storage/Memory.php b/src/OAuth2/Storage/Memory.php
index 2c60b71ce..c33bd0ebb 100644
--- a/src/OAuth2/Storage/Memory.php
+++ b/src/OAuth2/Storage/Memory.php
@@ -74,9 +74,9 @@ public function getAuthorizationCode($code)
         ), $this->authorizationCodes[$code]);
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
-        $this->authorizationCodes[$code] = compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token');
+        $this->authorizationCodes[$code] = compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method');
 
         return true;
     }
diff --git a/src/OAuth2/Storage/Mongo.php b/src/OAuth2/Storage/Mongo.php
index eea06e315..92f93d5b2 100644
--- a/src/OAuth2/Storage/Mongo.php
+++ b/src/OAuth2/Storage/Mongo.php
@@ -179,7 +179,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -192,6 +192,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                     'expires' => $expires,
                     'scope' => $scope,
                     'id_token' => $id_token,
+                    'code_challenge' => $code_challenge,
+                    'code_challenge_method' => $code_challenge_method,
                 ))
             );
         } else {
@@ -203,6 +205,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                 'expires' => $expires,
                 'scope' => $scope,
                 'id_token' => $id_token,
+                'code_challenge' => $code_challenge,
+                'code_challenge_method' => $code_challenge_method,
             );
             $this->collection('code_table')->insert($token);
         }
diff --git a/src/OAuth2/Storage/MongoDB.php b/src/OAuth2/Storage/MongoDB.php
index 64f740fc1..0b28a7797 100644
--- a/src/OAuth2/Storage/MongoDB.php
+++ b/src/OAuth2/Storage/MongoDB.php
@@ -32,6 +32,9 @@ class MongoDB implements AuthorizationCodeInterface,
 
     public function __construct($connection, $config = array())
     {
+        if (!class_exists(Database::class) || !class_exists(Client::class)) {
+            throw new \LogicException('Missing MongoDB php extension. Please install mongodb.so');
+        }
         if ($connection instanceof Database) {
             $this->db = $connection;
         } else {
@@ -167,7 +170,7 @@ public function getAuthorizationCode($code)
         return is_null($code) ? false : $code;
     }
 
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
@@ -180,6 +183,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
                     'expires' => $expires,
                     'scope' => $scope,
                     'id_token' => $id_token,
+                    'code_challenge' => $code_challenge,
+                    'code_challenge_method' => $code_challenge_method,
                 ))
             );
             return $result->getMatchedCount() > 0;
@@ -192,6 +197,8 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
             'expires' => $expires,
             'scope' => $scope,
             'id_token' => $id_token,
+            'code_challenge' => $code_challenge,
+            'code_challenge_method' => $code_challenge_method,
         );
         $result = $this->collection('code_table')->insertOne($token);
         return $result->getInsertedCount() > 0;
diff --git a/src/OAuth2/Storage/Pdo.php b/src/OAuth2/Storage/Pdo.php
index 074cee447..46c873359 100644
--- a/src/OAuth2/Storage/Pdo.php
+++ b/src/OAuth2/Storage/Pdo.php
@@ -247,7 +247,7 @@ public function getAuthorizationCode($code)
      * @param string $id_token
      * @return bool|mixed
      */
-    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         if (func_num_args() > 6) {
             // we are calling with an id token
@@ -259,12 +259,12 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
 
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
-            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope where authorization_code=:code', $this->config['code_table']));
+            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, code_challenge=:code_challenge, code_challenge_method=:code_challenge_method where authorization_code=:code', $this->config['code_table']));
         } else {
-            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope)', $this->config['code_table']));
+            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, code_challenge, code_challenge_method) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :code_challenge, :code_challenge_method)', $this->config['code_table']));
         }
 
-        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope'));
+        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'code_challenge', 'code_challenge_method'));
     }
 
     /**
@@ -277,19 +277,19 @@ public function setAuthorizationCode($code, $client_id, $user_id, $redirect_uri,
      * @param string $id_token
      * @return bool
      */
-    private function setAuthorizationCodeWithIdToken($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    private function setAuthorizationCodeWithIdToken($code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         // convert expires to datestring
         $expires = date('Y-m-d H:i:s', $expires);
 
         // if it exists, update it.
         if ($this->getAuthorizationCode($code)) {
-            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, id_token =:id_token where authorization_code=:code', $this->config['code_table']));
+            $stmt = $this->db->prepare($sql = sprintf('UPDATE %s SET client_id=:client_id, user_id=:user_id, redirect_uri=:redirect_uri, expires=:expires, scope=:scope, id_token =:id_token, code_challenge=:code_challenge, code_challenge_method=:code_challenge_method where authorization_code=:code', $this->config['code_table']));
         } else {
-            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, id_token) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :id_token)', $this->config['code_table']));
+            $stmt = $this->db->prepare(sprintf('INSERT INTO %s (authorization_code, client_id, user_id, redirect_uri, expires, scope, id_token, code_challenge, code_challenge_method) VALUES (:code, :client_id, :user_id, :redirect_uri, :expires, :scope, :id_token, :code_challenge, :code_challenge_method)', $this->config['code_table']));
         }
 
-        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'));
+        return $stmt->execute(compact('code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'));
     }
 
     /**
@@ -676,6 +676,8 @@ public function getBuildSql($dbName = 'oauth2_server_php')
               expires             TIMESTAMP      NOT NULL,
               scope               VARCHAR(4000),
               id_token            VARCHAR(1000),
+              code_challenge        VARCHAR(1000),
+              code_challenge_method VARCHAR(20),
               PRIMARY KEY (authorization_code)
             );
 
diff --git a/src/OAuth2/Storage/Redis.php b/src/OAuth2/Storage/Redis.php
index e6294e22d..5a41dfc22 100644
--- a/src/OAuth2/Storage/Redis.php
+++ b/src/OAuth2/Storage/Redis.php
@@ -95,11 +95,11 @@ public function getAuthorizationCode($code)
         return $this->getValue($this->config['code_key'] . $code);
     }
 
-    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null)
+    public function setAuthorizationCode($authorization_code, $client_id, $user_id, $redirect_uri, $expires, $scope = null, $id_token = null, $code_challenge = null, $code_challenge_method = null)
     {
         return $this->setValue(
             $this->config['code_key'] . $authorization_code,
-            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token'),
+            compact('authorization_code', 'client_id', 'user_id', 'redirect_uri', 'expires', 'scope', 'id_token', 'code_challenge', 'code_challenge_method'),
             $expires
         );
     }
diff --git a/src/OAuth2/TokenType/Bearer.php b/src/OAuth2/TokenType/Bearer.php
index 8ac8596ac..aa1094b1e 100644
--- a/src/OAuth2/TokenType/Bearer.php
+++ b/src/OAuth2/TokenType/Bearer.php
@@ -109,7 +109,7 @@ public function getAccessTokenParameter(RequestInterface $request, ResponseInter
             }
 
             $contentType = $request->server('CONTENT_TYPE');
-            if (false !== $pos = strpos($contentType, ';')) {
+            if (false !== $pos = strpos((string) $contentType, ';')) {
                 $contentType = substr($contentType, 0, $pos);
             }
 
diff --git a/test/OAuth2/Controller/AuthorizeControllerTest.php b/test/OAuth2/Controller/AuthorizeControllerTest.php
index fe3553b23..88f0d0da0 100644
--- a/test/OAuth2/Controller/AuthorizeControllerTest.php
+++ b/test/OAuth2/Controller/AuthorizeControllerTest.php
@@ -133,7 +133,7 @@ public function testDoNotEnforceState()
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
 
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertNotContains('error', $response->getHttpHeader('Location'));
+        $this->assertStringNotContainsString('error', $response->getHttpHeader('Location'));
     }
 
     public function testEnforceScope()
@@ -161,7 +161,7 @@ public function testEnforceScope()
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
 
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertNotContains('error', $response->getHttpHeader('Location'));
+        $this->assertStringNotContainsString('error', $response->getHttpHeader('Location'));
     }
 
     public function testInvalidRedirectUri()
@@ -227,7 +227,7 @@ public function testRedirectUriWithValidRedirectUri()
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
 
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertContains('code', $response->getHttpHeader('Location'));
+        $this->assertStringContainsString('code', $response->getHttpHeader('Location'));
     }
 
     public function testRedirectUriWithDifferentQueryAndExactMatchRequired()
@@ -263,7 +263,7 @@ public function testRedirectUriWithDifferentQueryAndExactMatchNotRequired()
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
 
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertContains('code', $response->getHttpHeader('Location'));
+        $this->assertStringContainsString('code', $response->getHttpHeader('Location'));
     }
 
     public function testMultipleRedirectUris()
@@ -278,14 +278,14 @@ public function testMultipleRedirectUris()
 
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertContains('code', $response->getHttpHeader('Location'));
+        $this->assertStringContainsString('code', $response->getHttpHeader('Location'));
 
         // call again with different (but still valid) redirect URI
         $request->query['redirect_uri'] = 'http://morehazards.com/';
 
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertContains('code', $response->getHttpHeader('Location'));
+        $this->assertStringContainsString('code', $response->getHttpHeader('Location'));
     }
 
     /**
@@ -303,7 +303,7 @@ public function testNoRedirectUriSuppliedDoesNotRequireTokenRedirectUri()
 
         $server->handleAuthorizeRequest($request, $response = new Response(), true);
         $this->assertEquals($response->getStatusCode(), 302);
-        $this->assertContains('state', $response->getHttpHeader('Location'));
+        $this->assertStringContainsString('state', $response->getHttpHeader('Location'));
         $this->assertStringStartsWith('http://brentertainment.com/?code=', $response->getHttpHeader('Location'));
 
         $parts = parse_url(http://github.com/$response-%3EgetHttpHeader('Location'));
@@ -421,7 +421,7 @@ public function testSuccessfulRequestStripsExtraParameters()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertFalse(isset($parts['fake']));
diff --git a/test/OAuth2/Encryption/FirebaseJwtTest.php b/test/OAuth2/Encryption/FirebaseJwtTest.php
index c7e92c053..63a5d4036 100644
--- a/test/OAuth2/Encryption/FirebaseJwtTest.php
+++ b/test/OAuth2/Encryption/FirebaseJwtTest.php
@@ -9,7 +9,7 @@ class FirebaseJwtTest extends TestCase
 {
     private $privateKey;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->privateKey = <<<EOD
 -----BEGIN RSA PRIVATE KEY-----
diff --git a/test/OAuth2/Encryption/JwtTest.php b/test/OAuth2/Encryption/JwtTest.php
index d73b4c923..376a922b1 100644
--- a/test/OAuth2/Encryption/JwtTest.php
+++ b/test/OAuth2/Encryption/JwtTest.php
@@ -9,7 +9,7 @@ class JwtTest extends TestCase
 {
     private $privateKey;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->privateKey = <<<EOD
 -----BEGIN RSA PRIVATE KEY-----
diff --git a/test/OAuth2/GrantType/JwtBearerTest.php b/test/OAuth2/GrantType/JwtBearerTest.php
index e60023b3c..4f6d67b2c 100644
--- a/test/OAuth2/GrantType/JwtBearerTest.php
+++ b/test/OAuth2/GrantType/JwtBearerTest.php
@@ -13,7 +13,7 @@ class JwtBearerTest extends TestCase
 {
     private $privateKey;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->privateKey = <<<EOD
 -----BEGIN RSA PRIVATE KEY-----
diff --git a/test/OAuth2/OpenID/ResponseType/CodeIdTokenTest.php b/test/OAuth2/OpenID/ResponseType/CodeIdTokenTest.php
index 7b892c946..f08322bd4 100644
--- a/test/OAuth2/OpenID/ResponseType/CodeIdTokenTest.php
+++ b/test/OAuth2/OpenID/ResponseType/CodeIdTokenTest.php
@@ -29,7 +29,7 @@ public function testHandleAuthorizeRequest()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('query', $parts);
@@ -87,7 +87,7 @@ public function testUserClaimsWithUserId()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('query', $parts);
@@ -133,7 +133,7 @@ public function testUserClaimsWithoutUserId()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('query', $parts);
diff --git a/test/OAuth2/OpenID/ResponseType/IdTokenTest.php b/test/OAuth2/OpenID/ResponseType/IdTokenTest.php
index a0df3a936..85f8abc86 100644
--- a/test/OAuth2/OpenID/ResponseType/IdTokenTest.php
+++ b/test/OAuth2/OpenID/ResponseType/IdTokenTest.php
@@ -52,7 +52,7 @@ public function testHandleAuthorizeRequest()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('fragment', $parts);
@@ -110,7 +110,7 @@ private function extractTokenDataFromResponse(Response $response)
     {
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('fragment', $parts);
diff --git a/test/OAuth2/OpenID/ResponseType/IdTokenTokenTest.php b/test/OAuth2/OpenID/ResponseType/IdTokenTokenTest.php
index 0573a9866..6d4cb14c3 100644
--- a/test/OAuth2/OpenID/ResponseType/IdTokenTokenTest.php
+++ b/test/OAuth2/OpenID/ResponseType/IdTokenTokenTest.php
@@ -31,7 +31,7 @@ public function testHandleAuthorizeRequest()
 
         $this->assertEquals($response->getStatusCode(), 302);
         $location = $response->getHttpHeader('Location');
-        $this->assertNotContains('error', $location);
+        $this->assertStringNotContainsString('error', $location);
 
         $parts = parse_url(http://github.com/$location);
         $this->assertArrayHasKey('fragment', $parts);
diff --git a/test/OAuth2/ResponseTest.php b/test/OAuth2/ResponseTest.php
index 172bc88fd..338f5cc93 100644
--- a/test/OAuth2/ResponseTest.php
+++ b/test/OAuth2/ResponseTest.php
@@ -14,7 +14,7 @@ public function testRenderAsXml()
         ));
 
         $string = $response->getResponseBody('xml');
-        $this->assertContains('<response><foo>bar</foo><halland>oates</halland></response>', $string);
+        $this->assertStringContainsString('<response><foo>bar</foo><halland>oates</halland></response>', $string);
     }
 
     public function testSetRedirect()
diff --git a/test/OAuth2/ResponseType/JwtAccessTokenTest.php b/test/OAuth2/ResponseType/JwtAccessTokenTest.php
index 6195d557a..ad90e535b 100644
--- a/test/OAuth2/ResponseType/JwtAccessTokenTest.php
+++ b/test/OAuth2/ResponseType/JwtAccessTokenTest.php
@@ -40,20 +40,20 @@ public function testCreateAccessToken()
         $this->assertEquals(3600, $delta);
         $this->assertEquals($decodedAccessToken['id'], $decodedAccessToken['jti']);
     }
-    
+
     public function testExtraPayloadCallback()
     {
         $jwtconfig = array('jwt_extra_payload_callable' => function() {
             return array('custom_param' => 'custom_value');
         });
-        
+
         $server = $this->getTestServer($jwtconfig);
         $jwtResponseType = $server->getResponseType('token');
-        
+
         $accessToken = $jwtResponseType->createAccessToken('Test Client ID', 123, 'test', false);
         $jwt = new Jwt;
         $decodedAccessToken = $jwt->decode($accessToken['access_token'], null, false);
-        
+
         $this->assertArrayHasKey('custom_param', $decodedAccessToken);
         $this->assertEquals('custom_value', $decodedAccessToken['custom_param']);
     }
@@ -162,7 +162,7 @@ private function getTestServer($jwtconfig = array())
         $memoryStorage = Bootstrap::getInstance()->getMemoryStorage();
 
         $storage = array(
-            'access_token' => new JwtAccessTokenStorage($memoryStorage),
+            'access_token' => new JwtAccessTokenStorage($memoryStorage, $memoryStorage),
             'client' => $memoryStorage,
             'client_credentials' => $memoryStorage,
         );
diff --git a/test/OAuth2/ServerTest.php b/test/OAuth2/ServerTest.php
index 3106961e2..fab526a6f 100644
--- a/test/OAuth2/ServerTest.php
+++ b/test/OAuth2/ServerTest.php
@@ -6,27 +6,26 @@
 use OAuth2\ResponseType\AuthorizationCode;
 use OAuth2\Storage\Bootstrap;
 use PHPUnit\Framework\TestCase;
+use Yoast\PHPUnitPolyfills\Polyfills\ExpectPHPException;
 
 class ServerTest extends TestCase
 {
-    /**
-     * @expectedException LogicException OAuth2\Storage\ClientInterface
-     **/
+    use ExpectPHPException;
+
     public function testGetAuthorizeControllerWithNoClientStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\ClientInterface');
         // must set Client Storage
         $server = new Server();
         $server->getAuthorizeController();
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\AccessTokenInterface
-     **/
     public function testGetAuthorizeControllerWithNoAccessTokenStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\AccessTokenInterface');
         // must set AccessToken or AuthorizationCode
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
         $server->getAuthorizeController();
     }
 
@@ -34,8 +33,8 @@ public function testGetAuthorizeControllerWithClientStorageAndAccessTokenRespons
     {
         // must set AccessToken or AuthorizationCode
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
-        $server->addResponseType($this->getMock('OAuth2\ResponseType\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
+        $server->addResponseType($this->createMock('OAuth2\ResponseType\AccessTokenInterface'));
 
         $this->assertNotNull($server->getAuthorizeController());
     }
@@ -44,21 +43,19 @@ public function testGetAuthorizeControllerWithClientStorageAndAuthorizationCodeR
     {
         // must set AccessToken or AuthorizationCode
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
-        $server->addResponseType($this->getMock('OAuth2\ResponseType\AuthorizationCodeInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
+        $server->addResponseType($this->createMock('OAuth2\ResponseType\AuthorizationCodeInterface'));
 
         $this->assertNotNull($server->getAuthorizeController());
     }
 
-    /**
-     * @expectedException LogicException allow_implicit
-     **/
     public function testGetAuthorizeControllerWithClientStorageAndAccessTokenStorageThrowsException()
     {
         // must set AuthorizationCode or AccessToken / implicit
+        $this->expectExceptionMessage('allow_implicit');
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'));
 
         $this->assertNotNull($server->getAuthorizeController());
     }
@@ -67,8 +64,8 @@ public function testGetAuthorizeControllerWithClientStorageAndAccessTokenStorage
     {
         // must set AuthorizationCode or AccessToken / implicit
         $server = new Server(array(), array('allow_implicit' => true));
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'));
 
         $this->assertNotNull($server->getAuthorizeController());
     }
@@ -77,63 +74,55 @@ public function testGetAuthorizeControllerWithClientStorageAndAuthorizationCodeS
     {
         // must set AccessToken or AuthorizationCode
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\AuthorizationCodeInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\AuthorizationCodeInterface'));
 
         $this->assertNotNull($server->getAuthorizeController());
     }
 
-    /**
-     * @expectedException LogicException grant_types
-     **/
     public function testGetTokenControllerWithGrantTypeStorageThrowsException()
     {
+        $this->expectExceptionMessage('grant_types');
         $server = new Server();
         $server->getTokenController();
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\ClientCredentialsInterface
-     **/
     public function testGetTokenControllerWithNoClientCredentialsStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\ClientCredentialsInterface');
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\UserCredentialsInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\UserCredentialsInterface'));
         $server->getTokenController();
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\AccessTokenInterface
-     **/
     public function testGetTokenControllerWithNoAccessTokenStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\AccessTokenInterface');
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientCredentialsInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientCredentialsInterface'));
         $server->getTokenController();
     }
 
     public function testGetTokenControllerWithAccessTokenAndClientCredentialsStorage()
     {
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientCredentialsInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientCredentialsInterface'));
         $server->getTokenController();
     }
 
     public function testGetTokenControllerAccessTokenStorageAndClientCredentialsStorageAndGrantTypes()
     {
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientCredentialsInterface'));
-        $server->addGrantType($this->getMockBuilder('OAuth2\GrantType\AuthorizationCode')->disableOriginalConstructor()->getMock());
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientCredentialsInterface'));
+        $server->addGrantType($this->createMock('OAuth2\GrantType\AuthorizationCode'));
         $server->getTokenController();
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\AccessTokenInterface
-     **/
     public function testGetResourceControllerWithNoAccessTokenStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\AccessTokenInterface');
         $server = new Server();
         $server->getResourceController();
     }
@@ -141,41 +130,35 @@ public function testGetResourceControllerWithNoAccessTokenStorageThrowsException
     public function testGetResourceControllerWithAccessTokenStorage()
     {
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'));
         $server->getResourceController();
     }
 
-    /**
-     * @expectedException InvalidArgumentException OAuth2\Storage\AccessTokenInterface
-     **/
     public function testAddingStorageWithInvalidClass()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\AccessTokenInterface');
         $server = new Server();
         $server->addStorage(new \StdClass());
     }
 
-    /**
-     * @expectedException InvalidArgumentException access_token
-     **/
     public function testAddingStorageWithInvalidKey()
     {
+        $this->expectExceptionMessage('access_token');
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'), 'nonexistant_storage');
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'), 'nonexistant_storage');
     }
 
-    /**
-     * @expectedException InvalidArgumentException OAuth2\Storage\AuthorizationCodeInterface
-     **/
     public function testAddingStorageWithInvalidKeyStorageCombination()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\AuthorizationCodeInterface');
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\AccessTokenInterface'), 'authorization_code');
+        $server->addStorage($this->createMock('OAuth2\Storage\AccessTokenInterface'), 'authorization_code');
     }
 
     public function testAddingStorageWithValidKeyOnlySetsThatKey()
     {
         $server = new Server();
-        $server->addStorage($this->getMock('OAuth2\Storage\Memory'), 'access_token');
+        $server->addStorage($this->createMock('OAuth2\Storage\Memory'), 'access_token');
 
         $reflection = new \ReflectionClass($server);
         $prop = $reflection->getProperty('storages');
@@ -191,7 +174,7 @@ public function testAddingStorageWithValidKeyOnlySetsThatKey()
     public function testAddingClientStorageSetsClientCredentialsStorageByDefault()
     {
         $server = new Server();
-        $memory = $this->getMock('OAuth2\Storage\Memory');
+        $memory = $this->createMock('OAuth2\Storage\Memory');
         $server->addStorage($memory, 'client');
 
         $client_credentials = $server->getStorage('client_credentials');
@@ -202,7 +185,7 @@ public function testAddingClientStorageSetsClientCredentialsStorageByDefault()
 
     public function testAddStorageWithNullValue()
     {
-        $memory = $this->getMock('OAuth2\Storage\Memory');
+        $memory = $this->createMock('OAuth2\Storage\Memory');
         $server = new Server($memory);
         $server->addStorage(null, 'refresh_token');
 
@@ -218,7 +201,7 @@ public function testAddStorageWithNullValue()
 
     public function testNewServerWithNullStorageValue()
     {
-        $memory = $this->getMock('OAuth2\Storage\Memory');
+        $memory = $this->createMock('OAuth2\Storage\Memory');
         $server = new Server(array(
             'client_credentials' => $memory,
             'refresh_token'      => null,
@@ -237,7 +220,7 @@ public function testNewServerWithNullStorageValue()
     public function testAddingClientCredentialsStorageSetsClientStorageByDefault()
     {
         $server = new Server();
-        $memory = $this->getMock('OAuth2\Storage\Memory');
+        $memory = $this->createMock('OAuth2\Storage\Memory');
         $server->addStorage($memory, 'client_credentials');
 
         $client = $server->getStorage('client');
@@ -249,10 +232,9 @@ public function testAddingClientCredentialsStorageSetsClientStorageByDefault()
     public function testSettingClientStorageByDefaultDoesNotOverrideSetStorage()
     {
         $server = new Server();
-        $pdo = $this->getMockBuilder('OAuth2\Storage\Pdo')
-            ->disableOriginalConstructor()->getMock();
+        $pdo = $this->createMock('OAuth2\Storage\Pdo');
 
-        $memory = $this->getMock('OAuth2\Storage\Memory');
+        $memory = $this->createMock('OAuth2\Storage\Memory');
 
         $server->addStorage($pdo, 'client');
         $server->addStorage($memory, 'client_credentials');
@@ -266,7 +248,7 @@ public function testSettingClientStorageByDefaultDoesNotOverrideSetStorage()
 
     public function testAddingResponseType()
     {
-        $storage = $this->getMock('OAuth2\Storage\Memory');
+        $storage = $this->createMock('OAuth2\Storage\Memory');
         $storage
           ->expects($this->any())
           ->method('getClientDetails')
@@ -323,7 +305,7 @@ public function testCustomClientAssertionType()
             'code' => 'testcode',
         ));
         // verify the mock clientAssertionType was called as expected
-        $clientAssertionType = $this->getMock('OAuth2\ClientAssertionType\ClientAssertionTypeInterface', array('validateRequest', 'getClientId'));
+        $clientAssertionType = $this->createMock('OAuth2\ClientAssertionType\ClientAssertionTypeInterface');
         $clientAssertionType
             ->expects($this->once())
             ->method('validateRequest')
@@ -420,98 +402,84 @@ public function testValidRefreshTokenWithNewRefreshTokenInResponse()
         $this->assertFalse($used_token, 'the refresh token used is no longer valid');
     }
 
-    /**
-     * @expectedException InvalidArgumentException OAuth2\ResponseType\AuthorizationCodeInterface
-     **/
     public function testAddingUnknownResponseTypeThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\ResponseType\AuthorizationCodeInterface');
         $server = new Server();
-        $server->addResponseType($this->getMock('OAuth2\ResponseType\ResponseTypeInterface'));
+        $server->addResponseType($this->createMock('OAuth2\ResponseType\ResponseTypeInterface'));
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\PublicKeyInterface
-     **/
     public function testUsingJwtAccessTokensWithoutPublicKeyStorageThrowsException()
     {
+        $this->expectExceptionMessage('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array(), array('use_jwt_access_tokens' => true));
-        $server->addGrantType($this->getMock('OAuth2\GrantType\GrantTypeInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientCredentialsInterface'));
-        $server->addStorage($this->getMock('OAuth2\Storage\ClientCredentialsInterface'));
+        $server->addGrantType($this->createMock('OAuth2\GrantType\GrantTypeInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientCredentialsInterface'));
+        $server->addStorage($this->createMock('OAuth2\Storage\ClientCredentialsInterface'));
 
         $server->getTokenController();
     }
 
     public function testUsingJustJwtAccessTokenStorageWithResourceControllerIsOkay()
     {
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($pubkey), array('use_jwt_access_tokens' => true));
 
         $this->assertNotNull($server->getResourceController());
         $this->assertInstanceOf('OAuth2\Storage\PublicKeyInterface', $server->getStorage('public_key'));
     }
 
-    /**
-     * @expectedException LogicException OAuth2\Storage\ClientInterface
-     **/
     public function testUsingJustJwtAccessTokenStorageWithAuthorizeControllerThrowsException()
     {
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $this->expectExceptionMessage('OAuth2\Storage\ClientInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($pubkey), array('use_jwt_access_tokens' => true));
         $this->assertNotNull($server->getAuthorizeController());
     }
 
-    /**
-     * @expectedException LogicException grant_types
-     **/
     public function testUsingJustJwtAccessTokenStorageWithTokenControllerThrowsException()
     {
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $this->expectExceptionMessage('grant_types');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($pubkey), array('use_jwt_access_tokens' => true));
         $server->getTokenController();
     }
 
     public function testUsingJwtAccessTokenAndClientStorageWithAuthorizeControllerIsOkay()
     {
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
         $server = new Server(array($pubkey, $client), array('use_jwt_access_tokens' => true, 'allow_implicit' => true));
         $this->assertNotNull($server->getAuthorizeController());
 
         $this->assertInstanceOf('OAuth2\ResponseType\JwtAccessToken', $server->getResponseType('token'));
     }
 
-    /**
-     * @expectedException LogicException UserClaims
-     **/
     public function testUsingOpenIDConnectWithoutUserClaimsThrowsException()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
+        $this->expectExceptionMessage('UserClaims');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
         $server = new Server($client, array('use_openid_connect' => true));
 
         $server->getAuthorizeController();
     }
 
-    /**
-     * @expectedException LogicException PublicKeyInterface
-     **/
     public function testUsingOpenIDConnectWithoutPublicKeyThrowsException()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OPenID\Storage\UserClaimsInterface');
+        $this->expectExceptionMessage('PublicKeyInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OPenID\Storage\UserClaimsInterface');
         $server = new Server(array($client, $userclaims), array('use_openid_connect' => true));
 
         $server->getAuthorizeController();
     }
 
-    /**
-     * @expectedException LogicException issuer
-     **/
     public function testUsingOpenIDConnectWithoutIssuerThrowsException()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $this->expectExceptionMessage('issuer');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($client, $userclaims, $pubkey), array('use_openid_connect' => true));
 
         $server->getAuthorizeController();
@@ -519,9 +487,9 @@ public function testUsingOpenIDConnectWithoutIssuerThrowsException()
 
     public function testUsingOpenIDConnectWithIssuerPublicKeyAndUserClaimsIsOkay()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($client, $userclaims, $pubkey), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy',
@@ -533,14 +501,12 @@ public function testUsingOpenIDConnectWithIssuerPublicKeyAndUserClaimsIsOkay()
         $this->assertNull($server->getResponseType('id_token token'));
     }
 
-    /**
-     * @expectedException LogicException OAuth2\ResponseType\AccessTokenInterface
-     **/
     public function testUsingOpenIDConnectWithAllowImplicitWithoutTokenStorageThrowsException()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $this->expectErrorMessage('OAuth2\ResponseType\AccessTokenInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($client, $userclaims, $pubkey), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy',
@@ -552,9 +518,9 @@ public function testUsingOpenIDConnectWithAllowImplicitWithoutTokenStorageThrows
 
     public function testUsingOpenIDConnectWithAllowImplicitAndUseJwtAccessTokensIsOkay()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
         $server = new Server(array($client, $userclaims, $pubkey), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy',
@@ -570,10 +536,10 @@ public function testUsingOpenIDConnectWithAllowImplicitAndUseJwtAccessTokensIsOk
 
     public function testUsingOpenIDConnectWithAllowImplicitAndAccessTokenStorageIsOkay()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
-        $token = $this->getMock('OAuth2\Storage\AccessTokenInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
+        $token = $this->createMock('OAuth2\Storage\AccessTokenInterface');
         $server = new Server(array($client, $userclaims, $pubkey, $token), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy',
@@ -588,17 +554,17 @@ public function testUsingOpenIDConnectWithAllowImplicitAndAccessTokenStorageIsOk
 
     public function testUsingOpenIDConnectWithAllowImplicitAndAccessTokenResponseTypeIsOkay()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
-        // $token = $this->getMock('OAuth2\Storage\AccessTokenInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
+        // $token = $this->createMock('OAuth2\Storage\AccessTokenInterface');
         $server = new Server(array($client, $userclaims, $pubkey), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy',
             'allow_implicit' => true,
         ));
 
-        $token = $this->getMock('OAuth2\ResponseType\AccessTokenInterface');
+        $token = $this->createMock('OAuth2\ResponseType\AccessTokenInterface');
         $server->addResponseType($token, 'token');
 
         $server->getAuthorizeController();
@@ -607,17 +573,15 @@ public function testUsingOpenIDConnectWithAllowImplicitAndAccessTokenResponseTyp
         $this->assertInstanceOf('OAuth2\OpenID\ResponseType\IdTokenTokenInterface', $server->getResponseType('id_token token'));
     }
 
-    /**
-     * @expectedException LogicException OAuth2\OpenID\Storage\AuthorizationCodeInterface
-     **/
     public function testUsingOpenIDConnectWithAuthorizationCodeStorageThrowsException()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientCredentialsInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
-        $token = $this->getMock('OAuth2\Storage\AccessTokenInterface');
-        $authcode = $this->getMock('OAuth2\Storage\AuthorizationCodeInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientCredentialsInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
+        $token = $this->createMock('OAuth2\Storage\AccessTokenInterface');
+        $authcode = $this->createMock('OAuth2\Storage\AuthorizationCodeInterface');
 
+        $this->expectErrorMessage('OAuth2\OpenID\Storage\AuthorizationCodeInterface');
         $server = new Server(array($client, $userclaims, $pubkey, $token, $authcode), array(
             'use_openid_connect' => true,
             'issuer' => 'someguy'
@@ -630,11 +594,11 @@ public function testUsingOpenIDConnectWithAuthorizationCodeStorageThrowsExceptio
 
     public function testUsingOpenIDConnectWithOpenIDAuthorizationCodeStorageCreatesOpenIDAuthorizationCodeGrantType()
     {
-        $client = $this->getMock('OAuth2\Storage\ClientCredentialsInterface');
-        $userclaims = $this->getMock('OAuth2\OpenID\Storage\UserClaimsInterface');
-        $pubkey = $this->getMock('OAuth2\Storage\PublicKeyInterface');
-        $token = $this->getMock('OAuth2\Storage\AccessTokenInterface');
-        $authcode = $this->getMock('OAuth2\OpenID\Storage\AuthorizationCodeInterface');
+        $client = $this->createMock('OAuth2\Storage\ClientCredentialsInterface');
+        $userclaims = $this->createMock('OAuth2\OpenID\Storage\UserClaimsInterface');
+        $pubkey = $this->createMock('OAuth2\Storage\PublicKeyInterface');
+        $token = $this->createMock('OAuth2\Storage\AccessTokenInterface');
+        $authcode = $this->createMock('OAuth2\OpenID\Storage\AuthorizationCodeInterface');
 
         $server = new Server(array($client, $userclaims, $pubkey, $token, $authcode), array(
             'use_openid_connect' => true,
@@ -648,7 +612,7 @@ public function testUsingOpenIDConnectWithOpenIDAuthorizationCodeStorageCreatesO
 
     public function testMultipleValuedResponseTypeOrderDoesntMatter()
     {
-        $responseType = $this->getMock('OAuth2\OpenID\ResponseType\IdTokenTokenInterface');
+        $responseType = $this->createMock('OAuth2\OpenID\ResponseType\IdTokenTokenInterface');
         $server = new Server(array(), array(), array(), array(
             'token id_token' => $responseType,
         ));
@@ -659,7 +623,7 @@ public function testMultipleValuedResponseTypeOrderDoesntMatter()
     public function testAddGrantTypeWithoutKey()
     {
         $server = new Server();
-        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->getMock('OAuth2\Storage\AuthorizationCodeInterface')));
+        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->createMock('OAuth2\Storage\AuthorizationCodeInterface')));
 
         $grantTypes = $server->getGrantTypes();
         $this->assertEquals('authorization_code', key($grantTypes));
@@ -668,7 +632,7 @@ public function testAddGrantTypeWithoutKey()
     public function testAddGrantTypeWithKey()
     {
         $server = new Server();
-        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->getMock('OAuth2\Storage\AuthorizationCodeInterface')), 'ac');
+        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->createMock('OAuth2\Storage\AuthorizationCodeInterface')), 'ac');
 
         $grantTypes = $server->getGrantTypes();
         $this->assertEquals('ac', key($grantTypes));
@@ -677,7 +641,7 @@ public function testAddGrantTypeWithKey()
     public function testAddGrantTypeWithKeyNotString()
     {
         $server = new Server();
-        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->getMock('OAuth2\Storage\AuthorizationCodeInterface')), 42);
+        $server->addGrantType(new \OAuth2\GrantType\AuthorizationCode($this->createMock('OAuth2\Storage\AuthorizationCodeInterface')), 42);
 
         $grantTypes = $server->getGrantTypes();
         $this->assertEquals('authorization_code', key($grantTypes));
diff --git a/test/OAuth2/Storage/PdoTest.php b/test/OAuth2/Storage/PdoTest.php
index 4599f69bf..9a7630423 100644
--- a/test/OAuth2/Storage/PdoTest.php
+++ b/test/OAuth2/Storage/PdoTest.php
@@ -2,8 +2,12 @@
 
 namespace OAuth2\Storage;
 
+use Yoast\PHPUnitPolyfills\Polyfills\ExpectPHPException;
+
 class PdoTest extends BaseTest
 {
+    use ExpectPHPException;
+
     public function testCreatePdoStorageUsingPdoClass()
     {
         $dsn = sprintf('sqlite:%s', Bootstrap::getInstance()->getSqliteDir());
@@ -30,11 +34,9 @@ public function testCreatePdoStorageUsingConfig()
         $this->assertNotNull($storage->getClientDetails('oauth_test_client'));
     }
 
-    /**
-     * @expectedException InvalidArgumentException dsn
-     */
     public function testCreatePdoStorageWithoutDSNThrowsException()
     {
+        $this->expectErrorMessage('dsn');
         $config = array('username' => 'brent', 'password' => 'brentisaballer');
         $storage = new Pdo($config);
     }
diff --git a/test/OAuth2/TokenType/BearerTest.php b/test/OAuth2/TokenType/BearerTest.php
index 71cca3bd9..021fc7f5a 100644
--- a/test/OAuth2/TokenType/BearerTest.php
+++ b/test/OAuth2/TokenType/BearerTest.php
@@ -35,6 +35,17 @@ public function testInvalidContentType()
         $this->assertEquals($response->getParameter('error_description'), 'The content type for POST requests must be "application/x-www-form-urlencoded"');
     }
 
+    public function testMissingContentTypeExpectsToBeCorrectContent()
+    {
+        $bearer = new Bearer();
+        $request = TestRequest::createPost(array(
+            'access_token' => 'ThisIsMyAccessToken'
+        ));
+
+        $param = $bearer->getAccessTokenParameter($request, $response = new Response());
+        $this->assertEquals($param, 'ThisIsMyAccessToken');
+    }
+
     public function testValidRequestUsingAuthorizationHeader()
     {
         $bearer = new Bearer();
diff --git a/test/cleanup.php b/test/cleanup.php
deleted file mode 100644
index 8663a901b..000000000
--- a/test/cleanup.php
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-require_once(dirname(__FILE__).'/../src/OAuth2/Autoloader.php');
-OAuth2\Autoloader::register();
-
-// register test classes
-OAuth2\Autoloader::register(dirname(__FILE__).'/lib');
-
-// register vendors if possible
-if (file_exists(__DIR__.'/../vendor/autoload.php')) {
-    require_once(__DIR__.'/../vendor/autoload.php');
-}
-
-// remove the dynamoDB database that was created for this build
-OAuth2\Storage\Bootstrap::getInstance()->cleanupTravisDynamoDb();
diff --git a/test/lib/OAuth2/Storage/Bootstrap.php b/test/lib/OAuth2/Storage/Bootstrap.php
index 8e428f9b5..66c93ae5b 100755
--- a/test/lib/OAuth2/Storage/Bootstrap.php
+++ b/test/lib/OAuth2/Storage/Bootstrap.php
@@ -68,7 +68,7 @@ public function getPostgresPdo()
     public function getPostgresDriver()
     {
         try {
-            $pdo = new \PDO('pgsql:host=localhost;dbname=oauth2_server_php', 'postgres');
+            $pdo = new \PDO('pgsql:host=localhost;dbname=oauth2_server_php', 'postgres', 'postgres');
 
             return $pdo;
         } catch (\PDOException $e) {
@@ -118,7 +118,7 @@ public function getMysqlPdo()
         if (!$this->mysql) {
             $pdo = null;
             try {
-                $pdo = new \PDO('mysql:host=localhost;', 'root');
+                $pdo = new \PDO('mysql:host=localhost;', 'root', 'root');
             } catch (\PDOException $e) {
                 $this->mysql = new NullStorage('MySQL', 'Unable to connect to MySQL on root@localhost');
             }
@@ -352,11 +352,11 @@ private function removeMysqlDb(\PDO $pdo)
 
     private function createPostgresDb()
     {
-        if (!`psql postgres -tAc "SELECT 1 FROM pg_roles WHERE rolname='postgres'"`) {
-            `createuser -s -r postgres`;
+        if (!`PGPASSWORD=postgres psql postgres -tAc "SELECT 1 FROM pg_roles WHERE rolname='postgres'" -h localhost -U postgres`) {
+            `PGPASSWORD=postgres createuser -s -r postgres -h localhost -U postgres`;
         }
 
-        `createdb -O postgres oauth2_server_php`;
+        `PGPASSWORD=postgres createdb -O postgres oauth2_server_php -h localhost -U postgres`;
     }
 
     private function populatePostgresDb(\PDO $pdo)
@@ -366,8 +366,8 @@ private function populatePostgresDb(\PDO $pdo)
 
     private function removePostgresDb()
     {
-        if (trim(`psql -l | grep oauth2_server_php | wc -l`)) {
-            `dropdb oauth2_server_php`;
+        if (trim(`PGPASSWORD=postgres psql -l -h localhost -U postgres | grep oauth2_server_php | wc -l`)) {
+            `PGPASSWORD=postgres dropdb oauth2_server_php -h localhost -U postgres`;
         }
     }
 
@@ -945,21 +945,6 @@ private function populateDynamoDb($client, $prefix = null)
         ));
     }
 
-    public function cleanupTravisDynamoDb($prefix = null)
-    {
-        if (is_null($prefix)) {
-            // skip this when not applicable
-            if (!$this->getEnvVar('TRAVIS') || self::DYNAMODB_PHP_VERSION != $this->getEnvVar('TRAVIS_PHP_VERSION')) {
-                return;
-            }
-
-            $prefix = sprintf('build_%s_', $this->getEnvVar('TRAVIS_JOB_NUMBER'));
-        }
-
-        $client = $this->getDynamoDbClient();
-        $this->deleteDynamoDb($client, $prefix);
-    }
-
     private function getEnvVar($var, $default = null)
     {
         return isset($_SERVER[$var]) ? $_SERVER[$var] : (getenv($var) ?: $default);