diff --git a/src/CodeGenerator/AbstractInjector.php b/src/CodeGenerator/AbstractInjector.php
index 74b4c897..ae447602 100644
--- a/src/CodeGenerator/AbstractInjector.php
+++ b/src/CodeGenerator/AbstractInjector.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/CodeGenerator/AutoloadGenerator.php b/src/CodeGenerator/AutoloadGenerator.php
index 2cf11fd0..da9cde08 100644
--- a/src/CodeGenerator/AutoloadGenerator.php
+++ b/src/CodeGenerator/AutoloadGenerator.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use SplFileObject;
diff --git a/src/CodeGenerator/FactoryGenerator.php b/src/CodeGenerator/FactoryGenerator.php
index 6266c1b3..7c0af979 100644
--- a/src/CodeGenerator/FactoryGenerator.php
+++ b/src/CodeGenerator/FactoryGenerator.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use SplFileObject;
diff --git a/src/CodeGenerator/FactoryInterface.php b/src/CodeGenerator/FactoryInterface.php
index f159a399..bfc0e3b6 100644
--- a/src/CodeGenerator/FactoryInterface.php
+++ b/src/CodeGenerator/FactoryInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/CodeGenerator/GeneratorTrait.php b/src/CodeGenerator/GeneratorTrait.php
index 47f2d5e1..f0b8f5c2 100644
--- a/src/CodeGenerator/GeneratorTrait.php
+++ b/src/CodeGenerator/GeneratorTrait.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use Zend\Di\Exception\GenerateCodeException;
diff --git a/src/CodeGenerator/InjectorGenerator.php b/src/CodeGenerator/InjectorGenerator.php
index 0c6e043c..4cde34fb 100644
--- a/src/CodeGenerator/InjectorGenerator.php
+++ b/src/CodeGenerator/InjectorGenerator.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\CodeGenerator;
 
 use Psr\Log\LoggerInterface;
diff --git a/src/Config.php b/src/Config.php
index 7eb16f18..175faaea 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 use ArrayAccess;
@@ -225,7 +227,7 @@ public function setTypePreference(string $type, string $preference, ?string $con
     public function setAlias(string $name, string $class) : self
     {
         if (! class_exists($class) && ! interface_exists($class)) {
-            throw new Exception\ClassNotFoundException('Could not find class "' . $class . '"');
+            throw new Exception\ClassNotFoundException($class);
         }
 
         $this->types[$name]['typeOf'] = $class;
diff --git a/src/ConfigInterface.php b/src/ConfigInterface.php
index 9de0e70e..a25fc09e 100644
--- a/src/ConfigInterface.php
+++ b/src/ConfigInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 /**
diff --git a/src/ConfigProvider.php b/src/ConfigProvider.php
index 54b5bc71..0ee13937 100644
--- a/src/ConfigProvider.php
+++ b/src/ConfigProvider.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 /**
diff --git a/src/Container/AutowireFactory.php b/src/Container/AutowireFactory.php
index 737cff90..adeea7c2 100644
--- a/src/Container/AutowireFactory.php
+++ b/src/Container/AutowireFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Container;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Container/ConfigFactory.php b/src/Container/ConfigFactory.php
index aa92e737..3708dbfa 100644
--- a/src/Container/ConfigFactory.php
+++ b/src/Container/ConfigFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Container;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Container/GeneratorFactory.php b/src/Container/GeneratorFactory.php
index 506bf05a..0b5be88a 100644
--- a/src/Container/GeneratorFactory.php
+++ b/src/Container/GeneratorFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Container;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Container/InjectorFactory.php b/src/Container/InjectorFactory.php
index a8ab44bc..49fdacb9 100644
--- a/src/Container/InjectorFactory.php
+++ b/src/Container/InjectorFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Container;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Container/ServiceManager/AutowireFactory.php b/src/Container/ServiceManager/AutowireFactory.php
index 169a57c2..49759148 100644
--- a/src/Container/ServiceManager/AutowireFactory.php
+++ b/src/Container/ServiceManager/AutowireFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Container\ServiceManager;
 
 use Interop\Container\ContainerInterface;
diff --git a/src/DefaultContainer.php b/src/DefaultContainer.php
index 1dc1a52d..b68cb60e 100644
--- a/src/DefaultContainer.php
+++ b/src/DefaultContainer.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Definition/ClassDefinitionInterface.php b/src/Definition/ClassDefinitionInterface.php
index 5d011c07..33d38b59 100644
--- a/src/Definition/ClassDefinitionInterface.php
+++ b/src/Definition/ClassDefinitionInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition;
 
 use ReflectionClass;
diff --git a/src/Definition/DefinitionInterface.php b/src/Definition/DefinitionInterface.php
index 0cfcb5d2..1209e6ae 100644
--- a/src/Definition/DefinitionInterface.php
+++ b/src/Definition/DefinitionInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition;
 
 /**
diff --git a/src/Definition/ParameterInterface.php b/src/Definition/ParameterInterface.php
index cab560e1..452f92a5 100644
--- a/src/Definition/ParameterInterface.php
+++ b/src/Definition/ParameterInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition;
 
 /**
diff --git a/src/Definition/Reflection/ClassDefinition.php b/src/Definition/Reflection/ClassDefinition.php
index 0aa661de..c7b3f56d 100644
--- a/src/Definition/Reflection/ClassDefinition.php
+++ b/src/Definition/Reflection/ClassDefinition.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition\Reflection;
 
 use ReflectionClass;
diff --git a/src/Definition/Reflection/Parameter.php b/src/Definition/Reflection/Parameter.php
index b8ae010b..aa8b2cc2 100644
--- a/src/Definition/Reflection/Parameter.php
+++ b/src/Definition/Reflection/Parameter.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition\Reflection;
 
 use ReflectionParameter;
diff --git a/src/Definition/RuntimeDefinition.php b/src/Definition/RuntimeDefinition.php
index 3732d636..e772e86a 100644
--- a/src/Definition/RuntimeDefinition.php
+++ b/src/Definition/RuntimeDefinition.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Definition;
 
 use Zend\Di\Definition\Reflection\ClassDefinition;
diff --git a/src/Exception/CircularDependencyException.php b/src/Exception/CircularDependencyException.php
index fd01c06a..3f10d394 100644
--- a/src/Exception/CircularDependencyException.php
+++ b/src/Exception/CircularDependencyException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 use DomainException;
diff --git a/src/Exception/ExceptionInterface.php b/src/Exception/ExceptionInterface.php
index 7197a40a..b01bd533 100644
--- a/src/Exception/ExceptionInterface.php
+++ b/src/Exception/ExceptionInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 use Throwable;
diff --git a/src/Exception/GenerateCodeException.php b/src/Exception/GenerateCodeException.php
index 7ab814b0..81de3774 100644
--- a/src/Exception/GenerateCodeException.php
+++ b/src/Exception/GenerateCodeException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 /**
diff --git a/src/Exception/InvalidArgumentException.php b/src/Exception/InvalidArgumentException.php
index 0fd4539e..3ecdb0d7 100644
--- a/src/Exception/InvalidArgumentException.php
+++ b/src/Exception/InvalidArgumentException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class InvalidArgumentException extends \InvalidArgumentException implements ExceptionInterface
diff --git a/src/Exception/InvalidCallbackException.php b/src/Exception/InvalidCallbackException.php
index fc249a14..c80e6aea 100644
--- a/src/Exception/InvalidCallbackException.php
+++ b/src/Exception/InvalidCallbackException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 /**
diff --git a/src/Exception/InvalidParamNameException.php b/src/Exception/InvalidParamNameException.php
index ab330297..7a4459b9 100644
--- a/src/Exception/InvalidParamNameException.php
+++ b/src/Exception/InvalidParamNameException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class InvalidParamNameException extends InvalidArgumentException
diff --git a/src/Exception/InvalidPositionException.php b/src/Exception/InvalidPositionException.php
index a4f798a1..2cb6601c 100644
--- a/src/Exception/InvalidPositionException.php
+++ b/src/Exception/InvalidPositionException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class InvalidPositionException extends InvalidArgumentException
diff --git a/src/Exception/LogicException.php b/src/Exception/LogicException.php
index a3622cfc..7f72a467 100644
--- a/src/Exception/LogicException.php
+++ b/src/Exception/LogicException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class LogicException extends \LogicException implements ExceptionInterface
diff --git a/src/Exception/MissingPropertyException.php b/src/Exception/MissingPropertyException.php
index 470aaa00..060b35fd 100644
--- a/src/Exception/MissingPropertyException.php
+++ b/src/Exception/MissingPropertyException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 use DomainException;
diff --git a/src/Exception/RuntimeException.php b/src/Exception/RuntimeException.php
index feb420a5..e250eaf3 100644
--- a/src/Exception/RuntimeException.php
+++ b/src/Exception/RuntimeException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class RuntimeException extends \RuntimeException implements ExceptionInterface
diff --git a/src/Exception/UndefinedReferenceException.php b/src/Exception/UndefinedReferenceException.php
index b9d5e289..3898d7df 100644
--- a/src/Exception/UndefinedReferenceException.php
+++ b/src/Exception/UndefinedReferenceException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 use DomainException;
diff --git a/src/Exception/UnexpectedValueException.php b/src/Exception/UnexpectedValueException.php
index fa46ac8a..839ce6a7 100644
--- a/src/Exception/UnexpectedValueException.php
+++ b/src/Exception/UnexpectedValueException.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Exception;
 
 class UnexpectedValueException extends \UnexpectedValueException implements ExceptionInterface
diff --git a/src/Injector.php b/src/Injector.php
index c554d8b4..9433d039 100644
--- a/src/Injector.php
+++ b/src/Injector.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 use Psr\Container\ContainerExceptionInterface;
diff --git a/src/InjectorInterface.php b/src/InjectorInterface.php
index 222bd59e..4286f16d 100644
--- a/src/InjectorInterface.php
+++ b/src/InjectorInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 /**
diff --git a/src/LegacyConfig.php b/src/LegacyConfig.php
index 8114b201..54d4ee13 100644
--- a/src/LegacyConfig.php
+++ b/src/LegacyConfig.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 use Traversable;
diff --git a/src/Module.php b/src/Module.php
index 70552921..494679a3 100644
--- a/src/Module.php
+++ b/src/Module.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di;
 
 /**
diff --git a/src/Resolver/AbstractInjection.php b/src/Resolver/AbstractInjection.php
index 639aae1c..f0bd5bed 100644
--- a/src/Resolver/AbstractInjection.php
+++ b/src/Resolver/AbstractInjection.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use const E_USER_DEPRECATED;
diff --git a/src/Resolver/DependencyResolver.php b/src/Resolver/DependencyResolver.php
index c50ac150..2be0e85a 100644
--- a/src/Resolver/DependencyResolver.php
+++ b/src/Resolver/DependencyResolver.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Resolver/DependencyResolverInterface.php b/src/Resolver/DependencyResolverInterface.php
index d747d903..ce3d7e2b 100644
--- a/src/Resolver/DependencyResolverInterface.php
+++ b/src/Resolver/DependencyResolverInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Resolver/InjectionInterface.php b/src/Resolver/InjectionInterface.php
index ae8ced66..c7698de2 100644
--- a/src/Resolver/InjectionInterface.php
+++ b/src/Resolver/InjectionInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Resolver/TypeInjection.php b/src/Resolver/TypeInjection.php
index e90c2098..ed6c076c 100644
--- a/src/Resolver/TypeInjection.php
+++ b/src/Resolver/TypeInjection.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use Psr\Container\ContainerInterface;
diff --git a/src/Resolver/ValueInjection.php b/src/Resolver/ValueInjection.php
index 6d935963..4f019eed 100644
--- a/src/Resolver/ValueInjection.php
+++ b/src/Resolver/ValueInjection.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace Zend\Di\Resolver;
 
 use Psr\Container\ContainerInterface;
diff --git a/templates/autoloader-class.template b/templates/autoloader-class.template
index 591ffd2d..1c4d2c17 100644
--- a/templates/autoloader-class.template
+++ b/templates/autoloader-class.template
@@ -3,6 +3,8 @@
  * Generated autoloader for Zend\Di
  */
 
+declare(strict_types=1);
+
 %namespace%
 use function spl_autoload_register;
 use function spl_autoload_unregister;
diff --git a/templates/autoloader-file.template b/templates/autoloader-file.template
index fe1010ea..38defa4c 100644
--- a/templates/autoloader-file.template
+++ b/templates/autoloader-file.template
@@ -3,6 +3,8 @@
  * Generated autoload file for Zend\Di
  */
 
+declare(strict_types=1);
+
 %namespace%
 require_once __DIR__ . '/Autoloader.php';
 
diff --git a/templates/factory-list.template b/templates/factory-list.template
index f6dd8583..a2e82243 100644
--- a/templates/factory-list.template
+++ b/templates/factory-list.template
@@ -3,6 +3,8 @@
  * Factory list generated by Zend\Di
  */
 
+declare(strict_types=1);
+
 return [
     %factories%
 ];
diff --git a/templates/factory.template b/templates/factory.template
index 57b81342..d1bc792c 100644
--- a/templates/factory.template
+++ b/templates/factory.template
@@ -3,6 +3,8 @@
  * Generated factory for %class%
  */
 
+declare(strict_types=1);
+
 %namespace%
 use Psr\Container\ContainerInterface;
 use Zend\Di\CodeGenerator\FactoryInterface;
diff --git a/templates/injector.template b/templates/injector.template
index bff4ce1f..c701422e 100644
--- a/templates/injector.template
+++ b/templates/injector.template
@@ -3,6 +3,8 @@
  * Injector generated by Zend\Di
  */
 
+declare(strict_types=1);
+
 %namespace%
 use Zend\Di\CodeGenerator\AbstractInjector;
 
diff --git a/test/CodeGenerator/AbstractInjectorTest.php b/test/CodeGenerator/AbstractInjectorTest.php
index dea1ea2f..c4c7e5d9 100644
--- a/test/CodeGenerator/AbstractInjectorTest.php
+++ b/test/CodeGenerator/AbstractInjectorTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\CodeGenerator;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/CodeGenerator/AutoloadGeneratorTest.php b/test/CodeGenerator/AutoloadGeneratorTest.php
index 719cac92..d70c64d0 100644
--- a/test/CodeGenerator/AutoloadGeneratorTest.php
+++ b/test/CodeGenerator/AutoloadGeneratorTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\CodeGenerator;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/CodeGenerator/FactoryGeneratorTest.php b/test/CodeGenerator/FactoryGeneratorTest.php
index 486ae7cd..70e39018 100644
--- a/test/CodeGenerator/FactoryGeneratorTest.php
+++ b/test/CodeGenerator/FactoryGeneratorTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\CodeGenerator;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/CodeGenerator/GeneratorTestTrait.php b/test/CodeGenerator/GeneratorTestTrait.php
index 1131f34c..4f52073a 100644
--- a/test/CodeGenerator/GeneratorTestTrait.php
+++ b/test/CodeGenerator/GeneratorTestTrait.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\CodeGenerator;
 
 use org\bovigo\vfs\vfsStream;
diff --git a/test/CodeGenerator/InjectorGeneratorTest.php b/test/CodeGenerator/InjectorGeneratorTest.php
index adb285f0..6fba2b84 100644
--- a/test/CodeGenerator/InjectorGeneratorTest.php
+++ b/test/CodeGenerator/InjectorGeneratorTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\CodeGenerator;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/ConfigProviderTest.php b/test/ConfigProviderTest.php
index e8c2145b..ddda6313 100644
--- a/test/ConfigProviderTest.php
+++ b/test/ConfigProviderTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\Constraint\IsType;
diff --git a/test/ConfigTest.php b/test/ConfigTest.php
index 91c2e040..ac10c91a 100644
--- a/test/ConfigTest.php
+++ b/test/ConfigTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Container/AutowireFactoryTest.php b/test/Container/AutowireFactoryTest.php
index ff464261..72e384c1 100644
--- a/test/Container/AutowireFactoryTest.php
+++ b/test/Container/AutowireFactoryTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Container;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Container/ConfigFactoryTest.php b/test/Container/ConfigFactoryTest.php
index f14db9d5..68744074 100644
--- a/test/Container/ConfigFactoryTest.php
+++ b/test/Container/ConfigFactoryTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Container;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Container/GeneratorFactoryTest.php b/test/Container/GeneratorFactoryTest.php
index 3d8eb3e1..d555312c 100644
--- a/test/Container/GeneratorFactoryTest.php
+++ b/test/Container/GeneratorFactoryTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Container;
 
 use org\bovigo\vfs\vfsStream;
diff --git a/test/Container/InjectorFactoryTest.php b/test/Container/InjectorFactoryTest.php
index b10e20e0..104ce9d0 100644
--- a/test/Container/InjectorFactoryTest.php
+++ b/test/Container/InjectorFactoryTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Container;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Container/ServiceManager/AutowireFactoryTest.php b/test/Container/ServiceManager/AutowireFactoryTest.php
index 441de542..91dbc1f3 100644
--- a/test/Container/ServiceManager/AutowireFactoryTest.php
+++ b/test/Container/ServiceManager/AutowireFactoryTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Container\ServiceManager;
 
 use Interop\Container\ContainerInterface;
diff --git a/test/DefaultContainerTest.php b/test/DefaultContainerTest.php
index ff755202..a472b312 100644
--- a/test/DefaultContainerTest.php
+++ b/test/DefaultContainerTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Definition/Reflection/ClassDefinitionTest.php b/test/Definition/Reflection/ClassDefinitionTest.php
index eb416bc7..ec2cd878 100644
--- a/test/Definition/Reflection/ClassDefinitionTest.php
+++ b/test/Definition/Reflection/ClassDefinitionTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Definition\Reflection;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Definition/Reflection/ParameterTest.php b/test/Definition/Reflection/ParameterTest.php
index 502fa4d2..47ab327c 100644
--- a/test/Definition/Reflection/ParameterTest.php
+++ b/test/Definition/Reflection/ParameterTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Definition\Reflection;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Definition/Reflection/ParameterTestTrait.php b/test/Definition/Reflection/ParameterTestTrait.php
index 24b9b356..36500692 100644
--- a/test/Definition/Reflection/ParameterTestTrait.php
+++ b/test/Definition/Reflection/ParameterTestTrait.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Definition\Reflection;
 
 use ReflectionClass;
diff --git a/test/Definition/RuntimeDefinitionTest.php b/test/Definition/RuntimeDefinitionTest.php
index cf01cd81..fa8a45ff 100644
--- a/test/Definition/RuntimeDefinitionTest.php
+++ b/test/Definition/RuntimeDefinitionTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Definition;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/InjectorTest.php b/test/InjectorTest.php
index 6b61c1fe..9d3aff05 100644
--- a/test/InjectorTest.php
+++ b/test/InjectorTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\Constraint;
diff --git a/test/LegacyConfigTest.php b/test/LegacyConfigTest.php
index 693e0d79..c33c83e6 100644
--- a/test/LegacyConfigTest.php
+++ b/test/LegacyConfigTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/ModuleTest.php b/test/ModuleTest.php
index 237b876d..cc76f86c 100644
--- a/test/ModuleTest.php
+++ b/test/ModuleTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 use PHPUnit\Framework\TestCase;
diff --git a/test/Resolver/AbstractInjectionTest.php b/test/Resolver/AbstractInjectionTest.php
index c24c847d..17380ed8 100644
--- a/test/Resolver/AbstractInjectionTest.php
+++ b/test/Resolver/AbstractInjectionTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Resolver;
 
 use PHPUnit\Framework\Error\Deprecated;
diff --git a/test/Resolver/DependencyResolverTest.php b/test/Resolver/DependencyResolverTest.php
index 32d852a3..2f219d43 100644
--- a/test/Resolver/DependencyResolverTest.php
+++ b/test/Resolver/DependencyResolverTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Resolver;
 
 use ArrayIterator;
diff --git a/test/Resolver/TypeInjectionTest.php b/test/Resolver/TypeInjectionTest.php
index acf90254..0e4726ab 100644
--- a/test/Resolver/TypeInjectionTest.php
+++ b/test/Resolver/TypeInjectionTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Resolver;
 
 use PHPUnit\Framework\Error\Deprecated;
diff --git a/test/Resolver/ValueInjectionTest.php b/test/Resolver/ValueInjectionTest.php
index e2ffa874..14e3be73 100644
--- a/test/Resolver/ValueInjectionTest.php
+++ b/test/Resolver/ValueInjectionTest.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Resolver;
 
 use PHPUnit\Framework\Error\Deprecated;
diff --git a/test/TestAsset/A.php b/test/TestAsset/A.php
index 051cf527..6ad09b94 100644
--- a/test/TestAsset/A.php
+++ b/test/TestAsset/A.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class A
diff --git a/test/TestAsset/B.php b/test/TestAsset/B.php
index 2309e7d6..abeebe07 100644
--- a/test/TestAsset/B.php
+++ b/test/TestAsset/B.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class B
diff --git a/test/TestAsset/BuiltinTypehintParameters.php b/test/TestAsset/BuiltinTypehintParameters.php
index 17093268..a2c69ddc 100644
--- a/test/TestAsset/BuiltinTypehintParameters.php
+++ b/test/TestAsset/BuiltinTypehintParameters.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class BuiltinTypehintParameters
diff --git a/test/TestAsset/CircularClasses/A.php b/test/TestAsset/CircularClasses/A.php
index 277f4b4e..5157b72a 100644
--- a/test/TestAsset/CircularClasses/A.php
+++ b/test/TestAsset/CircularClasses/A.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class A
diff --git a/test/TestAsset/CircularClasses/B.php b/test/TestAsset/CircularClasses/B.php
index 630f0deb..b22d0ca4 100644
--- a/test/TestAsset/CircularClasses/B.php
+++ b/test/TestAsset/CircularClasses/B.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class B
diff --git a/test/TestAsset/CircularClasses/C.php b/test/TestAsset/CircularClasses/C.php
index e34e091e..7c8aedb6 100644
--- a/test/TestAsset/CircularClasses/C.php
+++ b/test/TestAsset/CircularClasses/C.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class C
diff --git a/test/TestAsset/CircularClasses/D.php b/test/TestAsset/CircularClasses/D.php
index fbfde6a7..17edf39c 100644
--- a/test/TestAsset/CircularClasses/D.php
+++ b/test/TestAsset/CircularClasses/D.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class D
diff --git a/test/TestAsset/CircularClasses/E.php b/test/TestAsset/CircularClasses/E.php
index 4b1ccfef..e12d7c09 100644
--- a/test/TestAsset/CircularClasses/E.php
+++ b/test/TestAsset/CircularClasses/E.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class E
diff --git a/test/TestAsset/CircularClasses/X.php b/test/TestAsset/CircularClasses/X.php
index f03dc511..e2a3de8a 100644
--- a/test/TestAsset/CircularClasses/X.php
+++ b/test/TestAsset/CircularClasses/X.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class X
diff --git a/test/TestAsset/CircularClasses/Y.php b/test/TestAsset/CircularClasses/Y.php
index 8c3e7321..57f01941 100644
--- a/test/TestAsset/CircularClasses/Y.php
+++ b/test/TestAsset/CircularClasses/Y.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CircularClasses;
 
 class Y
diff --git a/test/TestAsset/CodeGenerator/StdClassFactory.php b/test/TestAsset/CodeGenerator/StdClassFactory.php
index ac6c75c2..0762caf6 100644
--- a/test/TestAsset/CodeGenerator/StdClassFactory.php
+++ b/test/TestAsset/CodeGenerator/StdClassFactory.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\CodeGenerator;
 
 use Psr\Container\ContainerInterface;
diff --git a/test/TestAsset/Constructor/EmptyConstructor.php b/test/TestAsset/Constructor/EmptyConstructor.php
index 154db7f4..90339c55 100644
--- a/test/TestAsset/Constructor/EmptyConstructor.php
+++ b/test/TestAsset/Constructor/EmptyConstructor.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class EmptyConstructor
diff --git a/test/TestAsset/Constructor/ManyArguments.php b/test/TestAsset/Constructor/ManyArguments.php
index f20215c3..07fe5007 100644
--- a/test/TestAsset/Constructor/ManyArguments.php
+++ b/test/TestAsset/Constructor/ManyArguments.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class ManyArguments
diff --git a/test/TestAsset/Constructor/MixedArguments.php b/test/TestAsset/Constructor/MixedArguments.php
index 9e5ab29d..d560ec96 100644
--- a/test/TestAsset/Constructor/MixedArguments.php
+++ b/test/TestAsset/Constructor/MixedArguments.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class MixedArguments
diff --git a/test/TestAsset/Constructor/NoConstructor.php b/test/TestAsset/Constructor/NoConstructor.php
index de80e42d..94632c0a 100644
--- a/test/TestAsset/Constructor/NoConstructor.php
+++ b/test/TestAsset/Constructor/NoConstructor.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class NoConstructor
diff --git a/test/TestAsset/Constructor/OptionalArguments.php b/test/TestAsset/Constructor/OptionalArguments.php
index d1c9d4be..da1f3069 100644
--- a/test/TestAsset/Constructor/OptionalArguments.php
+++ b/test/TestAsset/Constructor/OptionalArguments.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class OptionalArguments
diff --git a/test/TestAsset/Constructor/Php7.php b/test/TestAsset/Constructor/Php7.php
index d3dcf1de..bb69a3c5 100644
--- a/test/TestAsset/Constructor/Php7.php
+++ b/test/TestAsset/Constructor/Php7.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class Php7
diff --git a/test/TestAsset/Constructor/RequiredArguments.php b/test/TestAsset/Constructor/RequiredArguments.php
index a4135438..4b9953c9 100644
--- a/test/TestAsset/Constructor/RequiredArguments.php
+++ b/test/TestAsset/Constructor/RequiredArguments.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 use ArrayAccess;
diff --git a/test/TestAsset/Constructor/ThreeArguments.php b/test/TestAsset/Constructor/ThreeArguments.php
index 538558cb..366501d8 100644
--- a/test/TestAsset/Constructor/ThreeArguments.php
+++ b/test/TestAsset/Constructor/ThreeArguments.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Constructor;
 
 class ThreeArguments
diff --git a/test/TestAsset/DependencyTree/AdditionalLevel1.php b/test/TestAsset/DependencyTree/AdditionalLevel1.php
index bb243391..1e319014 100644
--- a/test/TestAsset/DependencyTree/AdditionalLevel1.php
+++ b/test/TestAsset/DependencyTree/AdditionalLevel1.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class AdditionalLevel1
diff --git a/test/TestAsset/DependencyTree/Complex.php b/test/TestAsset/DependencyTree/Complex.php
index c69683ae..81f1d175 100644
--- a/test/TestAsset/DependencyTree/Complex.php
+++ b/test/TestAsset/DependencyTree/Complex.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class Complex
diff --git a/test/TestAsset/DependencyTree/Level1.php b/test/TestAsset/DependencyTree/Level1.php
index 36c617da..ece8f8ac 100644
--- a/test/TestAsset/DependencyTree/Level1.php
+++ b/test/TestAsset/DependencyTree/Level1.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class Level1
diff --git a/test/TestAsset/DependencyTree/Level2.php b/test/TestAsset/DependencyTree/Level2.php
index d4bf913b..54b43cd0 100644
--- a/test/TestAsset/DependencyTree/Level2.php
+++ b/test/TestAsset/DependencyTree/Level2.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class Level2
diff --git a/test/TestAsset/DependencyTree/Level2Preference.php b/test/TestAsset/DependencyTree/Level2Preference.php
index 77c04e8f..488af772 100644
--- a/test/TestAsset/DependencyTree/Level2Preference.php
+++ b/test/TestAsset/DependencyTree/Level2Preference.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class Level2Preference extends Level2
diff --git a/test/TestAsset/DependencyTree/Simple.php b/test/TestAsset/DependencyTree/Simple.php
index 08ca6686..63b8c36d 100644
--- a/test/TestAsset/DependencyTree/Simple.php
+++ b/test/TestAsset/DependencyTree/Simple.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\DependencyTree;
 
 class Simple
diff --git a/test/TestAsset/DummyInterface.php b/test/TestAsset/DummyInterface.php
index 86f95e41..479276da 100644
--- a/test/TestAsset/DummyInterface.php
+++ b/test/TestAsset/DummyInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 interface DummyInterface
diff --git a/test/TestAsset/ExtendedB.php b/test/TestAsset/ExtendedB.php
index 25495231..7396eb03 100644
--- a/test/TestAsset/ExtendedB.php
+++ b/test/TestAsset/ExtendedB.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class ExtendedB extends B
diff --git a/test/TestAsset/Hierarchy/A.php b/test/TestAsset/Hierarchy/A.php
index edc10435..c65a79e7 100644
--- a/test/TestAsset/Hierarchy/A.php
+++ b/test/TestAsset/Hierarchy/A.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 class A
diff --git a/test/TestAsset/Hierarchy/B.php b/test/TestAsset/Hierarchy/B.php
index a1ff53a0..60f98ce9 100644
--- a/test/TestAsset/Hierarchy/B.php
+++ b/test/TestAsset/Hierarchy/B.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 class B extends A implements InterfaceC
diff --git a/test/TestAsset/Hierarchy/C.php b/test/TestAsset/Hierarchy/C.php
index d5683a67..74b45137 100644
--- a/test/TestAsset/Hierarchy/C.php
+++ b/test/TestAsset/Hierarchy/C.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 class C extends B
diff --git a/test/TestAsset/Hierarchy/InterfaceA.php b/test/TestAsset/Hierarchy/InterfaceA.php
index 379fdf03..22f944cc 100644
--- a/test/TestAsset/Hierarchy/InterfaceA.php
+++ b/test/TestAsset/Hierarchy/InterfaceA.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 interface InterfaceA
diff --git a/test/TestAsset/Hierarchy/InterfaceB.php b/test/TestAsset/Hierarchy/InterfaceB.php
index 23354fd8..a93aa351 100644
--- a/test/TestAsset/Hierarchy/InterfaceB.php
+++ b/test/TestAsset/Hierarchy/InterfaceB.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 interface InterfaceB
diff --git a/test/TestAsset/Hierarchy/InterfaceC.php b/test/TestAsset/Hierarchy/InterfaceC.php
index 5d16da08..318525b0 100644
--- a/test/TestAsset/Hierarchy/InterfaceC.php
+++ b/test/TestAsset/Hierarchy/InterfaceC.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Hierarchy;
 
 interface InterfaceC extends InterfaceA, InterfaceB
diff --git a/test/TestAsset/InvokableInterface.php b/test/TestAsset/InvokableInterface.php
index 97204d1d..c80b4c10 100644
--- a/test/TestAsset/InvokableInterface.php
+++ b/test/TestAsset/InvokableInterface.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 /**
diff --git a/test/TestAsset/IterableDependency.php b/test/TestAsset/IterableDependency.php
index 5ef84f92..a7c657e4 100644
--- a/test/TestAsset/IterableDependency.php
+++ b/test/TestAsset/IterableDependency.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class IterableDependency
diff --git a/test/TestAsset/Option1ForA.php b/test/TestAsset/Option1ForA.php
index 472685a1..eba0f213 100644
--- a/test/TestAsset/Option1ForA.php
+++ b/test/TestAsset/Option1ForA.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class Option1ForA extends A
diff --git a/test/TestAsset/Option2ForA.php b/test/TestAsset/Option2ForA.php
index 8d8843d4..a41638fe 100644
--- a/test/TestAsset/Option2ForA.php
+++ b/test/TestAsset/Option2ForA.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class Option2ForA extends A
diff --git a/test/TestAsset/Parameters.php b/test/TestAsset/Parameters.php
index 00ea9419..854a3554 100644
--- a/test/TestAsset/Parameters.php
+++ b/test/TestAsset/Parameters.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class Parameters
diff --git a/test/TestAsset/Pseudotypes/CallableImplementation.php b/test/TestAsset/Pseudotypes/CallableImplementation.php
index d2cf51ca..a4c54765 100644
--- a/test/TestAsset/Pseudotypes/CallableImplementation.php
+++ b/test/TestAsset/Pseudotypes/CallableImplementation.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Pseudotypes;
 
 class CallableImplementation
diff --git a/test/TestAsset/Pseudotypes/IteratorAggregateImplementation.php b/test/TestAsset/Pseudotypes/IteratorAggregateImplementation.php
index f1a0e2e3..147e8685 100644
--- a/test/TestAsset/Pseudotypes/IteratorAggregateImplementation.php
+++ b/test/TestAsset/Pseudotypes/IteratorAggregateImplementation.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Pseudotypes;
 
 use IteratorAggregate;
diff --git a/test/TestAsset/Pseudotypes/IteratorImplementation.php b/test/TestAsset/Pseudotypes/IteratorImplementation.php
index 92b8e2ca..657861d5 100644
--- a/test/TestAsset/Pseudotypes/IteratorImplementation.php
+++ b/test/TestAsset/Pseudotypes/IteratorImplementation.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Pseudotypes;
 
 use Iterator;
diff --git a/test/TestAsset/RequiresA.php b/test/TestAsset/RequiresA.php
index 1d5eb264..3728ad29 100644
--- a/test/TestAsset/RequiresA.php
+++ b/test/TestAsset/RequiresA.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class RequiresA
diff --git a/test/TestAsset/Resolver/ExportableValue.php b/test/TestAsset/Resolver/ExportableValue.php
index 215327b9..3efdc973 100644
--- a/test/TestAsset/Resolver/ExportableValue.php
+++ b/test/TestAsset/Resolver/ExportableValue.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Resolver;
 
 class ExportableValue
diff --git a/test/TestAsset/Resolver/UnexportableValue1.php b/test/TestAsset/Resolver/UnexportableValue1.php
index bca0f2ef..f384ace3 100644
--- a/test/TestAsset/Resolver/UnexportableValue1.php
+++ b/test/TestAsset/Resolver/UnexportableValue1.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Resolver;
 
 class UnexportableValue1
diff --git a/test/TestAsset/Resolver/UnexportableValue2.php b/test/TestAsset/Resolver/UnexportableValue2.php
index e02bf1c0..5db78a8a 100644
--- a/test/TestAsset/Resolver/UnexportableValue2.php
+++ b/test/TestAsset/Resolver/UnexportableValue2.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset\Resolver;
 
 class UnexportableValue2
diff --git a/test/TestAsset/ScalarTypehintParameters.php b/test/TestAsset/ScalarTypehintParameters.php
index e23cb7ba..1d19a3ea 100644
--- a/test/TestAsset/ScalarTypehintParameters.php
+++ b/test/TestAsset/ScalarTypehintParameters.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class ScalarTypehintParameters
diff --git a/test/TestAsset/TypelessDependency.php b/test/TestAsset/TypelessDependency.php
index 5379acb6..c958c172 100644
--- a/test/TestAsset/TypelessDependency.php
+++ b/test/TestAsset/TypelessDependency.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\TestAsset;
 
 class TypelessDependency
diff --git a/test/_files/expected-codegen-results/autoload-file.php b/test/_files/expected-codegen-results/autoload-file.php
index 3f5fd873..3cf1c44e 100644
--- a/test/_files/expected-codegen-results/autoload-file.php
+++ b/test/_files/expected-codegen-results/autoload-file.php
@@ -3,6 +3,8 @@
  * Generated autoload file for Zend\Di
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Generated;
 
 require_once __DIR__ . '/Autoloader.php';
diff --git a/test/_files/expected-codegen-results/autoloader-class.php b/test/_files/expected-codegen-results/autoloader-class.php
index 2923176c..580276c1 100644
--- a/test/_files/expected-codegen-results/autoloader-class.php
+++ b/test/_files/expected-codegen-results/autoloader-class.php
@@ -3,6 +3,8 @@
  * Generated autoloader for Zend\Di
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Generated;
 
 use function spl_autoload_register;
diff --git a/test/_files/expected-codegen-results/factories-file.php b/test/_files/expected-codegen-results/factories-file.php
index 5cb4f2a3..3ef026e0 100644
--- a/test/_files/expected-codegen-results/factories-file.php
+++ b/test/_files/expected-codegen-results/factories-file.php
@@ -3,6 +3,8 @@
  * Factory list generated by Zend\Di
  */
 
+declare(strict_types=1);
+
 return [
     'ZendTest\\Di\\TestAsset\\A' => 'ZendTest\\Di\\Generated\\Factory\\ZendTest\\Di\\TestAsset\\AFactory',
     'ZendTest\\Di\\TestAsset\\B' => 'ZendTest\\Di\\Generated\\Factory\\ZendTest\\Di\\TestAsset\\BFactory',
diff --git a/test/_files/expected-codegen-results/factories/with-params.php b/test/_files/expected-codegen-results/factories/with-params.php
index 967252ef..a50da808 100644
--- a/test/_files/expected-codegen-results/factories/with-params.php
+++ b/test/_files/expected-codegen-results/factories/with-params.php
@@ -3,6 +3,8 @@
  * Generated factory for \ZendTest\Di\TestAsset\Constructor\MixedArguments
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Generated\Factory\ZendTest\Di\TestAsset\Constructor;
 
 use Psr\Container\ContainerInterface;
diff --git a/test/_files/expected-codegen-results/factories/without-params.php b/test/_files/expected-codegen-results/factories/without-params.php
index 2600044c..5b3ad200 100644
--- a/test/_files/expected-codegen-results/factories/without-params.php
+++ b/test/_files/expected-codegen-results/factories/without-params.php
@@ -3,6 +3,8 @@
  * Generated factory for \ZendTest\Di\TestAsset\A
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Generated\Factory\ZendTest\Di\TestAsset;
 
 use Psr\Container\ContainerInterface;
diff --git a/test/_files/expected-codegen-results/injector-class.php b/test/_files/expected-codegen-results/injector-class.php
index f12fa73d..0bcb01a7 100644
--- a/test/_files/expected-codegen-results/injector-class.php
+++ b/test/_files/expected-codegen-results/injector-class.php
@@ -3,6 +3,8 @@
  * Injector generated by Zend\Di
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di\Generated;
 
 use Zend\Di\CodeGenerator\AbstractInjector;
diff --git a/test/_files/legacy-configs/common.php b/test/_files/legacy-configs/common.php
index 2bfcc6b4..799c95a0 100644
--- a/test/_files/legacy-configs/common.php
+++ b/test/_files/legacy-configs/common.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 return [
diff --git a/test/_files/preferences/common.php b/test/_files/preferences/common.php
index 5642d74f..ca273097 100644
--- a/test/_files/preferences/common.php
+++ b/test/_files/preferences/common.php
@@ -5,6 +5,8 @@
  * @license   https://github.com/zendframework/zend-di/blob/master/LICENSE.md New BSD License
  */
 
+declare(strict_types=1);
+
 namespace ZendTest\Di;
 
 return [