diff --git a/Form/Type/PriorityType.php b/Form/Type/PriorityType.php
index 55eaf6c7..a3750bae 100644
--- a/Form/Type/PriorityType.php
+++ b/Form/Type/PriorityType.php
@@ -5,6 +5,7 @@
 use Hackzilla\Bundle\TicketBundle\Model\TicketMessageInterface;
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+use Symfony\Component\HttpKernel\Kernel;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 class PriorityType extends AbstractType
@@ -12,14 +13,14 @@ class PriorityType extends AbstractType
     public function configureOptions(OptionsResolver $resolver)
     {
         $choices = TicketMessageInterface::PRIORITIES;
-        unset($choices[0]);
+        unset($choices[TicketMessageInterface::PRIORITY_INVALID]);
 
-        $resolver->setDefaults(
-            [
-                'choices_as_values' => true,
-                'choices'           => array_flip($choices),
-            ]
-        );
+        // Workaround for symfony/options-resolver >= 2.7, < 3.1.
+        if ($resolver->hasDefault('choices_as_values') && version_compare(Kernel::VERSION, '3.1', '<')) {
+            $resolver->setDefaults(['choices' => array_flip($choices), 'choices_as_values' => true]);
+        } else {
+            $resolver->setDefaults(['choices' => array_flip($choices)]);
+        }
     }
 
     public function getParent()
diff --git a/Form/Type/StatusType.php b/Form/Type/StatusType.php
index b6be34b4..49cc4b8a 100644
--- a/Form/Type/StatusType.php
+++ b/Form/Type/StatusType.php
@@ -5,6 +5,7 @@
 use Hackzilla\Bundle\TicketBundle\Model\TicketMessageInterface;
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+use Symfony\Component\HttpKernel\Kernel;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 class StatusType extends AbstractType
@@ -12,14 +13,14 @@ class StatusType extends AbstractType
     public function configureOptions(OptionsResolver $resolver)
     {
         $choices = TicketMessageInterface::STATUSES;
-        unset($choices[0]);
+        unset($choices[TicketMessageInterface::STATUS_INVALID]);
 
-        $resolver->setDefaults(
-            [
-                'choices_as_values' => true,
-                'choices'           => array_flip($choices),
-            ]
-        );
+        // Workaround for symfony/options-resolver >= 2.7, < 3.1.
+        if ($resolver->hasDefault('choices_as_values') && version_compare(Kernel::VERSION, '3.1', '<')) {
+            $resolver->setDefaults(['choices' => array_flip($choices), 'choices_as_values' => true]);
+        } else {
+            $resolver->setDefaults(['choices' => array_flip($choices)]);
+        }
     }
 
     public function getParent()
diff --git a/Tests/EventListener/UserLoadTest.php b/Tests/EventListener/UserLoadTest.php
index 6015a6cf..aecf2ce0 100644
--- a/Tests/EventListener/UserLoadTest.php
+++ b/Tests/EventListener/UserLoadTest.php
@@ -19,10 +19,7 @@ public function setUp()
 
     public function getUserManagerMock()
     {
-        return $this
-            ->getMockBuilder(UserManager::class)
-            ->disableOriginalConstructor()
-            ->getMock();
+        return $this->createMock(UserManager::class);
     }
 
     public function tearDown()
diff --git a/Tests/Form/Type/TicketMessageTypeTest.php b/Tests/Form/Type/TicketMessageTypeTest.php
index d055d943..968ed9dd 100644
--- a/Tests/Form/Type/TicketMessageTypeTest.php
+++ b/Tests/Form/Type/TicketMessageTypeTest.php
@@ -15,7 +15,7 @@ class TicketMessageTypeTest extends TypeTestCase
 
     protected function setUp()
     {
-        $this->user = $this->getMockBuilder(UserManagerInterface::class)->getMock();
+        $this->user = $this->createMock(UserManagerInterface::class);
 
         parent::setUp();
     }
diff --git a/Tests/Form/Type/TicketTypeTest.php b/Tests/Form/Type/TicketTypeTest.php
index 32c282f0..1d7a659b 100644
--- a/Tests/Form/Type/TicketTypeTest.php
+++ b/Tests/Form/Type/TicketTypeTest.php
@@ -17,7 +17,7 @@ class TicketTypeTest extends TypeTestCase
 
     protected function setUp()
     {
-        $this->user = $this->getMockBuilder(UserManagerInterface::class)->getMock();
+        $this->user = $this->createMock(UserManagerInterface::class);
 
         parent::setUp();
     }
@@ -41,7 +41,7 @@ public function testSubmitValidData()
     {
         $formData = [];
 
-        $data = new \Hackzilla\Bundle\TicketBundle\Entity\Ticket();
+        $data = new Ticket();
 
         $form = $this->factory->create(TicketType::class);
 
diff --git a/Tests/Functional/TestKernel.php b/Tests/Functional/TestKernel.php
index e3bec424..1c72cd66 100644
--- a/Tests/Functional/TestKernel.php
+++ b/Tests/Functional/TestKernel.php
@@ -78,6 +78,11 @@ protected function configureContainer(ContainerBuilder $c, LoaderInterface $load
         ]);
 
         // SecurityBundle config
+        $mainFirewallConfig = ['anonymous' => null];
+        // "logout_on_user_change" configuration was marked as mandatory since version 3.4 and deprecated as of 4.1.
+        if (version_compare(self::VERSION, '3.4', '>=') && version_compare(self::VERSION, '4.1', '<')) {
+            $mainFirewallConfig['logout_on_user_change'] = true;
+        }
         $c->loadFromExtension('security', [
             'providers' => [
                 'in_memory' => [
@@ -85,9 +90,7 @@ protected function configureContainer(ContainerBuilder $c, LoaderInterface $load
                 ],
             ],
             'firewalls' => [
-                'main' => [
-                    'anonymous' => null,
-                ],
+                'main' => $mainFirewallConfig,
             ],
         ]);
 
@@ -105,6 +108,17 @@ protected function configureContainer(ContainerBuilder $c, LoaderInterface $load
             ],
         ]);
 
+        // TwigBundle config
+        $twigConfig = [
+            'strict_variables' => '%kernel.debug%',
+            'autoescape'       => 'name',
+        ];
+        // "default_path" configuration is available since version 3.4.
+        if (version_compare(self::VERSION, '3.4', '>=')) {
+            $twigConfig['default_path'] = __DIR__.'/Resources/views';
+        }
+        $c->loadFromExtension('twig', $twigConfig);
+
         // HackzillaBundle config
         $c->loadFromExtension('hackzilla_ticket', [
             'user_class' => User::class,
diff --git a/Tests/Manager/UserManagerTest.php b/Tests/Manager/UserManagerTest.php
index 0c7e58d9..669e072e 100644
--- a/Tests/Manager/UserManagerTest.php
+++ b/Tests/Manager/UserManagerTest.php
@@ -35,12 +35,7 @@ public function setUp()
 
     private function getMockUserRepository()
     {
-        $userRepository = $this
-            ->getMockBuilder(EntityRepository::class)
-            ->disableOriginalConstructor()
-            ->getMock();
-
-        return $userRepository;
+        return $this->createMock(EntityRepository::class);
     }
 
     public function tearDown()
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index c373c024..bb3f10ed 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -11,7 +11,7 @@
          bootstrap="Tests/bootstrap.php"
 >
     <php>
-        <env name="SYMFONY_DEPRECATIONS_HELPER" value="weak" />
+        <env name="SYMFONY_DEPRECATIONS_HELPER" value="max[direct]=1" />
     </php>
     <testsuites>
         <testsuite name="HackzillaTicketBundle test suite">