diff --git a/Tests/Command/CachePoolDeleteCommandTest.php b/Tests/Command/CachePoolDeleteCommandTest.php
index e22d85420..143364eac 100644
--- a/Tests/Command/CachePoolDeleteCommandTest.php
+++ b/Tests/Command/CachePoolDeleteCommandTest.php
@@ -23,7 +23,7 @@ class CachePoolDeleteCommandTest extends TestCase
 {
     private $cachePool;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $this->cachePool = $this->getMockBuilder(CacheItemPoolInterface::class)
             ->getMock();
diff --git a/Tests/Command/XliffLintCommandTest.php b/Tests/Command/XliffLintCommandTest.php
index 1729351a7..542272da5 100644
--- a/Tests/Command/XliffLintCommandTest.php
+++ b/Tests/Command/XliffLintCommandTest.php
@@ -131,13 +131,13 @@ private function getKernelAwareApplicationMock()
         return $application;
     }
 
-    protected function setUp()
+    protected function setUp(): void
     {
         @mkdir(sys_get_temp_dir().'/xliff-lint-test');
         $this->files = [];
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         foreach ($this->files as $file) {
             if (file_exists($file)) {
diff --git a/Tests/Functional/CachePoolListCommandTest.php b/Tests/Functional/CachePoolListCommandTest.php
index e9b8ed5e3..a76234697 100644
--- a/Tests/Functional/CachePoolListCommandTest.php
+++ b/Tests/Functional/CachePoolListCommandTest.php
@@ -20,7 +20,7 @@
  */
 class CachePoolListCommandTest extends AbstractWebTestCase
 {
-    protected function setUp()
+    protected function setUp(): void
     {
         static::bootKernel(['test_case' => 'CachePools', 'root_config' => 'config.yml']);
     }
diff --git a/Tests/Functional/RouterDebugCommandTest.php b/Tests/Functional/RouterDebugCommandTest.php
index a13a4e9fc..c7c7ac9ac 100644
--- a/Tests/Functional/RouterDebugCommandTest.php
+++ b/Tests/Functional/RouterDebugCommandTest.php
@@ -21,7 +21,7 @@ class RouterDebugCommandTest extends AbstractWebTestCase
 {
     private $application;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $kernel = static::createKernel(['test_case' => 'RouterDebug', 'root_config' => 'config.yml']);
         $this->application = new Application($kernel);
diff --git a/Tests/Functional/TranslationDebugCommandTest.php b/Tests/Functional/TranslationDebugCommandTest.php
index de4c293c0..8ce0ce060 100644
--- a/Tests/Functional/TranslationDebugCommandTest.php
+++ b/Tests/Functional/TranslationDebugCommandTest.php
@@ -21,7 +21,7 @@ class TranslationDebugCommandTest extends AbstractWebTestCase
 {
     private $application;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $kernel = static::createKernel(['test_case' => 'TransDebug', 'root_config' => 'config.yml']);
         $this->application = new Application($kernel);