diff --git a/src/DoctrineNullableEmbeddables/Annotations/Nullable.php b/src/DoctrineNullableEmbeddables/Annotations/Nullable.php
index e446cde..4ad3af6 100644
--- a/src/DoctrineNullableEmbeddables/Annotations/Nullable.php
+++ b/src/DoctrineNullableEmbeddables/Annotations/Nullable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Fmasa\DoctrineNullableEmbeddables\Annotations;
 
 /**
diff --git a/src/DoctrineNullableEmbeddables/Subscriber.php b/src/DoctrineNullableEmbeddables/Subscriber.php
index e36f559..4084f4c 100644
--- a/src/DoctrineNullableEmbeddables/Subscriber.php
+++ b/src/DoctrineNullableEmbeddables/Subscriber.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Fmasa\DoctrineNullableEmbeddables;
 
 use Doctrine\Common\Annotations\Reader;
diff --git a/tests/SubscriberTest.php b/tests/SubscriberTest.php
index fde49e7..ca5daf6 100644
--- a/tests/SubscriberTest.php
+++ b/tests/SubscriberTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Fmasa\DoctrineNullableEmbeddables;
 
 use Doctrine\Common\Annotations\AnnotationReader;
diff --git a/tests/stubs/Embeddable.php b/tests/stubs/Embeddable.php
index a81d1a4..993f28f 100644
--- a/tests/stubs/Embeddable.php
+++ b/tests/stubs/Embeddable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Doctrine\ORM\Mapping as ORM;
 
 
diff --git a/tests/stubs/EntityWithNestedEmbeddable.php b/tests/stubs/EntityWithNestedEmbeddable.php
index 186ab93..dd94d80 100644
--- a/tests/stubs/EntityWithNestedEmbeddable.php
+++ b/tests/stubs/EntityWithNestedEmbeddable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Doctrine\ORM\Mapping as ORM;
 use Fmasa\DoctrineNullableEmbeddables\Annotations\Nullable;
 
diff --git a/tests/stubs/NestedEmbeddable.php b/tests/stubs/NestedEmbeddable.php
index 2f11c16..56a476a 100644
--- a/tests/stubs/NestedEmbeddable.php
+++ b/tests/stubs/NestedEmbeddable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Doctrine\ORM\Mapping as ORM;
 use Fmasa\DoctrineNullableEmbeddables\Annotations\Nullable;
 
diff --git a/tests/stubs/SimpleEntity.php b/tests/stubs/SimpleEntity.php
index a389767..cc3af7c 100644
--- a/tests/stubs/SimpleEntity.php
+++ b/tests/stubs/SimpleEntity.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Fmasa\DoctrineNullableEmbeddables\Annotations\Nullable;
 use Doctrine\ORM\Mapping as ORM;