diff --git a/.phan/config.php b/.phan/config.php
index fcb6935..17d0da4 100644
--- a/.phan/config.php
+++ b/.phan/config.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 $default = include __DIR__ . '/../vendor/jbzoo/codestyle/src/phan/default.php';
 
 return array_merge($default, [
diff --git a/src/var-dumper.php b/src/var-dumper.php
index 5a9bb1d..470ad01 100644
--- a/src/var-dumper.php
+++ b/src/var-dumper.php
@@ -11,9 +11,10 @@
  * @license    MIT
  * @copyright  Copyright (C) JBZoo.com, All rights reserved.
  * @link       https://github.com/JBZoo/Toolbox-Dev
- * @author     Denis Smetannikov <denis@jbzoo.com>
  */
 
+declare(strict_types=1);
+
 use Symfony\Component\VarDumper\Cloner\VarCloner;
 use Symfony\Component\VarDumper\Dumper\CliDumper;
 use Symfony\Component\VarDumper\VarDumper;
diff --git a/tests/ToolboxDevCodestyleTest.php b/tests/ToolboxDevCodestyleTest.php
index 0ccfda7..676ea8d 100644
--- a/tests/ToolboxDevCodestyleTest.php
+++ b/tests/ToolboxDevCodestyleTest.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 namespace JBZoo\PHPUnit;
 
 /**
diff --git a/tests/ToolboxDevComposerTest.php b/tests/ToolboxDevComposerTest.php
index fdc621d..17a4efb 100644
--- a/tests/ToolboxDevComposerTest.php
+++ b/tests/ToolboxDevComposerTest.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 namespace JBZoo\PHPUnit;
 
 /**
diff --git a/tests/ToolboxDevCopyrightTest.php b/tests/ToolboxDevCopyrightTest.php
index 5a19509..2cdc29c 100644
--- a/tests/ToolboxDevCopyrightTest.php
+++ b/tests/ToolboxDevCopyrightTest.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 namespace JBZoo\PHPUnit;
 
 /**
@@ -25,5 +27,6 @@ class ToolboxDevCopyrightTest extends AbstractCopyrightTest
     /**
      * @var string
      */
-    protected $packageName = 'Toolbox-Dev';
+    protected $packageName     = 'Toolbox-Dev';
+    protected $isPhpStrictType = true;
 }
diff --git a/tests/ToolboxDevReadmeTest.php b/tests/ToolboxDevReadmeTest.php
index 5639a34..8e5bbcb 100644
--- a/tests/ToolboxDevReadmeTest.php
+++ b/tests/ToolboxDevReadmeTest.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 namespace JBZoo\PHPUnit;
 
 /**
diff --git a/tests/ToolboxDevTest.php b/tests/ToolboxDevTest.php
index 0f02b99..be1a2d7 100644
--- a/tests/ToolboxDevTest.php
+++ b/tests/ToolboxDevTest.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 namespace JBZoo\PHPUnit;
 
 /**
diff --git a/tests/autoload.php b/tests/autoload.php
index 2449a8d..004d4fa 100644
--- a/tests/autoload.php
+++ b/tests/autoload.php
@@ -13,6 +13,8 @@
  * @link       https://github.com/JBZoo/Toolbox-Dev
  */
 
+declare(strict_types=1);
+
 // main autoload
 if ($autoload = realpath('./vendor/autoload.php')) {
     require_once $autoload;