diff --git a/typo3/sysext/extbase/Tests/Fixture/ClassWithGettersAndSetters.php b/typo3/sysext/extbase/Tests/Fixture/ClassWithGettersAndSetters.php
index c8771ff10fe960462c00065cf7a18598795f312f..85a305fce5a38e37554523c4212a370bc3789ab1 100644
--- a/typo3/sysext/extbase/Tests/Fixture/ClassWithGettersAndSetters.php
+++ b/typo3/sysext/extbase/Tests/Fixture/ClassWithGettersAndSetters.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/ClassWithSetters.php b/typo3/sysext/extbase/Tests/Fixture/ClassWithSetters.php
index ceecc53b734c2b31f584cd575be54bccc35b5eb5..4c39cb0c0adc0e9238d974c5934b7bcd1666ed20 100644
--- a/typo3/sysext/extbase/Tests/Fixture/ClassWithSetters.php
+++ b/typo3/sysext/extbase/Tests/Fixture/ClassWithSetters.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/ClassWithSettersAndConstructor.php b/typo3/sysext/extbase/Tests/Fixture/ClassWithSettersAndConstructor.php
index 3412bd77417e7c3dc6fb8151bffca26b516fe8a3..f01f48159a0562877caa021aed8e325717399aaa 100644
--- a/typo3/sysext/extbase/Tests/Fixture/ClassWithSettersAndConstructor.php
+++ b/typo3/sysext/extbase/Tests/Fixture/ClassWithSettersAndConstructor.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/DummyClass.php b/typo3/sysext/extbase/Tests/Fixture/DummyClass.php
index 3cbee31fe32414dfa04d1fd52e3e6b20e7dd4ef6..53e645073b14dd49bbd03b49bf72dec68dde4097 100644
--- a/typo3/sysext/extbase/Tests/Fixture/DummyClass.php
+++ b/typo3/sysext/extbase/Tests/Fixture/DummyClass.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/Entity.php b/typo3/sysext/extbase/Tests/Fixture/Entity.php
index 97fa85a47f442c4ad87c57c9de2a45e73d5ff8d6..fdce5b70d303fd160106fbe616f16ab5abe77a32 100644
--- a/typo3/sysext/extbase/Tests/Fixture/Entity.php
+++ b/typo3/sysext/extbase/Tests/Fixture/Entity.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/SecondDummyClass.php b/typo3/sysext/extbase/Tests/Fixture/SecondDummyClass.php
index dc5615db8edde0202062173f842e016e09cf5f80..f7c7f8cf80abe3974f0a135f5ebd82b41642cf36 100644
--- a/typo3/sysext/extbase/Tests/Fixture/SecondDummyClass.php
+++ b/typo3/sysext/extbase/Tests/Fixture/SecondDummyClass.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/SlotFixture.php b/typo3/sysext/extbase/Tests/Fixture/SlotFixture.php
index b6db599c5fba7b1949295bff0ffc75d99d518503..bb32429b2976399c1439809669ef8a2f7ac5934e 100644
--- a/typo3/sysext/extbase/Tests/Fixture/SlotFixture.php
+++ b/typo3/sysext/extbase/Tests/Fixture/SlotFixture.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/TxClassWithGettersAndSetters.php b/typo3/sysext/extbase/Tests/Fixture/TxClassWithGettersAndSetters.php
index 0ae322aa998996e8a3bb2c280d02afecaf4f6055..6add7129f6bac6069b9b62ec620001f9a62db05b 100644
--- a/typo3/sysext/extbase/Tests/Fixture/TxClassWithGettersAndSetters.php
+++ b/typo3/sysext/extbase/Tests/Fixture/TxClassWithGettersAndSetters.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *
diff --git a/typo3/sysext/extbase/Tests/Fixture/ValueObject.php b/typo3/sysext/extbase/Tests/Fixture/ValueObject.php
index 12e456f80ce0881f0df0aa7cd0132ad955a207c6..e1c21d517df9c189bf1d30195c8c4f69fc88d2e9 100644
--- a/typo3/sysext/extbase/Tests/Fixture/ValueObject.php
+++ b/typo3/sysext/extbase/Tests/Fixture/ValueObject.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the TYPO3 CMS project.
  *