diff --git a/composer.json b/composer.json
index a2ffe14..ecebcfa 100644
--- a/composer.json
+++ b/composer.json
@@ -12,11 +12,15 @@
   "description": "Symfony JWT authentication with support for asymmetric keys and externally loaded secrets",
   "autoload": {
     "psr-4": {
-      "KleijnWeb\\JwtBundle\\Tests\\": "tests/unit",
-      "KleijnWeb\\JwtBundle\\Tests\\Functional\\": "tests/functional",
       "KleijnWeb\\JwtBundle\\": "src"
     }
   },
+  "autoload-dev": {
+    "psr-4": {
+      "KleijnWeb\\JwtBundle\\Tests\\": "tests/unit",
+      "KleijnWeb\\JwtBundle\\Tests\\Functional\\": "tests/functional"
+    }
+  },
   "require": {
     "php": "^7.0.0",
     "symfony/dependency-injection": ">=2.8.7",
@@ -30,8 +34,7 @@
     "symfony/security-bundle": ">=2.8.7"
   },
   "require-dev": {
-    "phpunit/phpunit": "^5.2",
-    "phpunit/phpunit-mock-objects": "^3.1",
+    "phpunit/phpunit": "^6.5",
     "symfony/framework-bundle": ">=2.8.7",
     "symfony/browser-kit": ">=2.8.7",
     "symfony/form": ">=2.8.7",
diff --git a/src/Jwt/JwtKey.php b/src/Jwt/JwtKey.php
index 924c8ba..1d1029a 100644
--- a/src/Jwt/JwtKey.php
+++ b/src/Jwt/JwtKey.php
@@ -91,7 +91,7 @@ public function __construct(array $options)
 
         $options                = array_merge($defaults, $options);
         $this->issuer           = $options['issuer'];
-        $this->audience         = $options['audience'];
+        $this->audience         = is_array($options['audience']) ? $options['audience'] : [$options['audience']];
         $this->type             = $options['type'];
         $this->minIssueTime     = $options['minIssueTime'];
         $this->requiredClaims   = $options['require'];
diff --git a/tests/functional/App/app/TestKernel.php b/tests/functional/App/app/TestKernel.php
index 040b146..18589d1 100644
--- a/tests/functional/App/app/TestKernel.php
+++ b/tests/functional/App/app/TestKernel.php
@@ -29,6 +29,6 @@ public function registerBundles()
      */
     public function registerContainerConfiguration(LoaderInterface $loader)
     {
-        $loader->load(__DIR__ . '/config_' . $this->getEnvironment() .'.yml');
+        $loader->load(__DIR__ . '/config_' . $this->getEnvironment() . '.yml');
     }
 }
diff --git a/tests/functional/TestCacheSmashingPHPUnitListener.php b/tests/functional/TestCacheSmashingPHPUnitListener.php
index 15b9847..b2f9251 100644
--- a/tests/functional/TestCacheSmashingPHPUnitListener.php
+++ b/tests/functional/TestCacheSmashingPHPUnitListener.php
@@ -8,61 +8,68 @@
 
 namespace KleijnWeb\JwtBundle\Tests\Functional;
 
-use PHPUnit_Framework_Test;
-use PHPUnit_Framework_AssertionFailedError;
 use Exception;
-use PHPUnit_Framework_TestSuite;
+use PHPUnit\Framework\AssertionFailedError;
+use PHPUnit\Framework\Test;
+use PHPUnit\Framework\TestListener;
+use PHPUnit\Framework\TestSuite;
+use PHPUnit\Framework\Warning;
 
-class TestCacheSmashingPHPUnitListener implements \PHPUnit_Framework_TestListener
+class TestCacheSmashingPHPUnitListener implements TestListener
 {
     const SUITE_NAME = 'Functional';
 
-    public function addError(PHPUnit_Framework_Test $test, Exception $e, $time)
+    public function addError(Test $test, Exception $e, $time)
     {
         //NOOP
     }
 
-    public function addFailure(PHPUnit_Framework_Test $test, PHPUnit_Framework_AssertionFailedError $e, $time)
+    public function addFailure(Test $test, AssertionFailedError $e, $time)
     {
         //NOOP
     }
 
-    public function addIncompleteTest(PHPUnit_Framework_Test $test, Exception $e, $time)
+    public function addIncompleteTest(Test $test, Exception $e, $time)
     {
         //NOOP
     }
 
-    public function addRiskyTest(PHPUnit_Framework_Test $test, Exception $e, $time)
+    public function addRiskyTest(Test $test, Exception $e, $time)
     {
         //NOOP
     }
 
-    public function addSkippedTest(PHPUnit_Framework_Test $test, Exception $e, $time)
+    public function addSkippedTest(Test $test, Exception $e, $time)
     {
         //NOOP
     }
 
-    public function startTest(PHPUnit_Framework_Test $test)
+    public function addWarning(Test $test, Warning $e, $time)
     {
         //NOOP
     }
 
-    public function endTest(PHPUnit_Framework_Test $test, $time)
+    public function startTest(Test $test)
     {
         //NOOP
     }
 
-    public function startTestSuite(PHPUnit_Framework_TestSuite $suite)
+    public function endTest(Test $test, $time)
+    {
+        //NOOP
+    }
+
+    public function startTestSuite(TestSuite $suite)
     {
         $this->smashIfFunctionalSuite($suite);
     }
 
-    public function endTestSuite(PHPUnit_Framework_TestSuite $suite)
+    public function endTestSuite(TestSuite $suite)
     {
         $this->smashIfFunctionalSuite($suite);
     }
 
-    private function smashIfFunctionalSuite(PHPUnit_Framework_TestSuite $suite)
+    private function smashIfFunctionalSuite(TestSuite $suite)
     {
         if ($suite->getName() !== self::SUITE_NAME) {
             return;
diff --git a/tests/unit/Authentication/JwtAuthenticationProviderTest.php b/tests/unit/Authentication/JwtAuthenticationProviderTest.php
index e737b69..39bb728 100644
--- a/tests/unit/Authentication/JwtAuthenticationProviderTest.php
+++ b/tests/unit/Authentication/JwtAuthenticationProviderTest.php
@@ -14,6 +14,7 @@
 use KleijnWeb\JwtBundle\Jwt\JwtToken;
 use KleijnWeb\JwtBundle\User\JwtUserProvider;
 use KleijnWeb\JwtBundle\User\UnsafeGroupsUserInterface;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\Authentication\Token\AnonymousToken;
 use Symfony\Component\Security\Core\Authentication\Token\PreAuthenticatedToken;
 use Symfony\Component\Security\Core\Exception\BadCredentialsException;
@@ -23,7 +24,7 @@
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class JwtAuthenticationProviderTest extends \PHPUnit_Framework_TestCase
+class JwtAuthenticationProviderTest extends TestCase
 {
     const ISSUER = 'http://api.server1.com/oauth2/token';
     const SECRET = 'A Pre-Shared Key';
diff --git a/tests/unit/Firewall/JwtAuthenticationListenerTest.php b/tests/unit/Firewall/JwtAuthenticationListenerTest.php
index fc7bc2e..9943430 100644
--- a/tests/unit/Firewall/JwtAuthenticationListenerTest.php
+++ b/tests/unit/Firewall/JwtAuthenticationListenerTest.php
@@ -10,6 +10,7 @@
 use KleijnWeb\JwtBundle\Authentication\JwtAuthenticatedToken;
 use KleijnWeb\JwtBundle\Authentication\JwtAuthenticationToken;
 use KleijnWeb\JwtBundle\Firewall\JwtAuthenticationListener;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\GetResponseEvent;
 use Symfony\Component\Security\Core\Authentication\AuthenticationManagerInterface;
@@ -19,7 +20,7 @@
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class JwtAuthenticationListenerTest extends \PHPUnit_Framework_TestCase
+class JwtAuthenticationListenerTest extends TestCase
 {
     /**
      * @var AuthenticationManagerInterface
diff --git a/tests/unit/Jwt/DecoderTest.php b/tests/unit/Jwt/DecoderTest.php
index 6a5ba46..5c0d14a 100644
--- a/tests/unit/Jwt/DecoderTest.php
+++ b/tests/unit/Jwt/DecoderTest.php
@@ -8,11 +8,12 @@
 namespace KleijnWeb\JwtBundle\Tests\Jwt;
 
 use KleijnWeb\JwtBundle\Jwt\Decoder;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class DecoderTest extends \PHPUnit_Framework_TestCase
+class DecoderTest extends TestCase
 {
     /**
      * @test
diff --git a/tests/unit/Jwt/EncoderTest.php b/tests/unit/Jwt/EncoderTest.php
index 4cdd472..5af24fd 100644
--- a/tests/unit/Jwt/EncoderTest.php
+++ b/tests/unit/Jwt/EncoderTest.php
@@ -8,11 +8,12 @@
 namespace KleijnWeb\JwtBundle\Tests\Jwt;
 
 use KleijnWeb\JwtBundle\Jwt\Encoder;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class EncoderTest extends \PHPUnit_Framework_TestCase
+class EncoderTest extends TestCase
 {
     /**
      * @param string $data
diff --git a/tests/unit/Jwt/JwtKeyTest.php b/tests/unit/Jwt/JwtKeyTest.php
index 1c34a35..9087daf 100644
--- a/tests/unit/Jwt/JwtKeyTest.php
+++ b/tests/unit/Jwt/JwtKeyTest.php
@@ -14,11 +14,12 @@
 use KleijnWeb\JwtBundle\Jwt\SecretLoader;
 use KleijnWeb\JwtBundle\Jwt\SignatureValidator\HmacValidator;
 use KleijnWeb\JwtBundle\Jwt\SignatureValidator\RsaValidator;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class JwtKeyTest extends \PHPUnit_Framework_TestCase
+class JwtKeyTest extends TestCase
 {
     /**
      * @test
diff --git a/tests/unit/Jwt/JwtTokenTest.php b/tests/unit/Jwt/JwtTokenTest.php
index 9deb392..ce08c80 100644
--- a/tests/unit/Jwt/JwtTokenTest.php
+++ b/tests/unit/Jwt/JwtTokenTest.php
@@ -9,11 +9,12 @@
 
 use KleijnWeb\JwtBundle\Jwt\JwtToken;
 use KleijnWeb\JwtBundle\Jwt\SignatureValidator\SignatureValidator;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class JwtTokenTest extends \PHPUnit_Framework_TestCase
+class JwtTokenTest extends TestCase
 {
     // @codingStandardsIgnoreStart
     const EXAMPLE_TOKEN = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ';
diff --git a/tests/unit/Jwt/SignatureValidator/HmacValidatorTest.php b/tests/unit/Jwt/SignatureValidator/HmacValidatorTest.php
index d5e1fee..f68cdc6 100644
--- a/tests/unit/Jwt/SignatureValidator/HmacValidatorTest.php
+++ b/tests/unit/Jwt/SignatureValidator/HmacValidatorTest.php
@@ -9,11 +9,12 @@
 namespace KleijnWeb\JwtBundle\Tests\Jwt\SignatureValidator;
 
 use KleijnWeb\JwtBundle\Jwt\SignatureValidator\HmacValidator;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class HmacValidatorTest extends \PHPUnit_Framework_TestCase
+class HmacValidatorTest extends TestCase
 {
     /**
      * @var string
diff --git a/tests/unit/Jwt/SignatureValidator/RsaValidatorTest.php b/tests/unit/Jwt/SignatureValidator/RsaValidatorTest.php
index b154641..56aaa92 100644
--- a/tests/unit/Jwt/SignatureValidator/RsaValidatorTest.php
+++ b/tests/unit/Jwt/SignatureValidator/RsaValidatorTest.php
@@ -9,11 +9,12 @@
 namespace KleijnWeb\JwtBundle\Tests\Jwt\SignatureValidator;
 
 use KleijnWeb\JwtBundle\Jwt\SignatureValidator\RsaValidator;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class RsaValidatorTest extends \PHPUnit_Framework_TestCase
+class RsaValidatorTest extends TestCase
 {
     /**
      * @var string
@@ -27,6 +28,7 @@ class RsaValidatorTest extends \PHPUnit_Framework_TestCase
 m6IDw3fRhZQrVwZ816/eN+1sqpIMZF4oo4kRA4b64U04ex67A/6BwDDQ3LH0mD4d
 EwIDAQAB
 -----END PUBLIC KEY-----';
+
     /**
      * @var string
      */
@@ -81,21 +83,21 @@ public static function testSetProvider()
     {
         // SHA256
 
-        $payload1 = 'some payload';
+        $payload1   = 'some payload';
         $signature1 = '';
         openssl_sign($payload1, $signature1, self::$privKey, RsaValidator::SHA256);
 
-        $payload2 = 'some other payload';
+        $payload2   = 'some other payload';
         $signature2 = '';
         openssl_sign($payload2, $signature2, self::$privKey, RsaValidator::SHA256);
 
         // SHA512
 
-        $payload3 = 'some payload';
+        $payload3   = 'some payload';
         $signature3 = '';
         openssl_sign($payload3, $signature3, self::$privKey, RsaValidator::SHA512);
 
-        $payload4 = 'some other payload';
+        $payload4   = 'some other payload';
         $signature4 = '';
         openssl_sign($payload4, $signature4, self::$privKey, RsaValidator::SHA512);
 
diff --git a/tests/unit/User/JwtUserProviderTest.php b/tests/unit/User/JwtUserProviderTest.php
index eccfb98..6e291e0 100644
--- a/tests/unit/User/JwtUserProviderTest.php
+++ b/tests/unit/User/JwtUserProviderTest.php
@@ -8,14 +8,15 @@
 namespace KleijnWeb\JwtBundle\Tests\User;
 
 use KleijnWeb\JwtBundle\Jwt\JwtToken;
-use KleijnWeb\JwtBundle\User\JwtUserProvider;
 use KleijnWeb\JwtBundle\User\JwtUser;
+use KleijnWeb\JwtBundle\User\JwtUserProvider;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\User\UserInterface;
 
 /**
  * @author John Kleijn <john@kleijnweb.nl>
  */
-class JwtUserProviderTest extends \PHPUnit_Framework_TestCase
+class JwtUserProviderTest extends TestCase
 {
     /**
      * @var JwtUserProvider