diff --git a/src/Definition/ArrayDefinition.php b/src/Definition/ArrayDefinition.php
index fd0f8b48..b36eb343 100644
--- a/src/Definition/ArrayDefinition.php
+++ b/src/Definition/ArrayDefinition.php
@@ -42,7 +42,7 @@ public function replaceNestedDefinitions(callable $replacer) : void
 
     public function __toString() : string
     {
-        $str = '[' . \PHP_EOL;
+        $str = '[' . "\n";
 
         foreach ($this->values as $key => $value) {
             if (is_string($key)) {
@@ -52,12 +52,12 @@ public function __toString() : string
             $str .= '    ' . $key . ' => ';
 
             if ($value instanceof Definition) {
-                $str .= str_replace(\PHP_EOL, \PHP_EOL . '    ', (string) $value);
+                $str .= str_replace("\n", "\n" . '    ', (string) $value);
             } else {
                 $str .= var_export($value, true);
             }
 
-            $str .= ',' . \PHP_EOL;
+            $str .= ',' . "\n";
         }
 
         return $str . ']';
diff --git a/src/Definition/Dumper/ObjectDefinitionDumper.php b/src/Definition/Dumper/ObjectDefinitionDumper.php
index c59c5100..2cf2389c 100644
--- a/src/Definition/Dumper/ObjectDefinitionDumper.php
+++ b/src/Definition/Dumper/ObjectDefinitionDumper.php
@@ -35,7 +35,7 @@ public function dump(ObjectDefinition $definition) : string
         $str = sprintf('    class = %s%s', $warning, $className);
 
         // Lazy
-        $str .= \PHP_EOL . '    lazy = ' . var_export($definition->isLazy(), true);
+        $str .= "\n" . '    lazy = ' . var_export($definition->isLazy(), true);
 
         if ($classExist) {
             // Constructor
@@ -48,7 +48,7 @@ public function dump(ObjectDefinition $definition) : string
             $str .= $this->dumpMethods($className, $definition);
         }
 
-        return sprintf('Object (' . \PHP_EOL . '%s' . \PHP_EOL . ')', $str);
+        return sprintf('Object (' . "\n" . '%s' . "\n" . ')', $str);
     }
 
     /**
@@ -63,7 +63,7 @@ private function dumpConstructor(string $className, ObjectDefinition $definition
         if ($constructorInjection !== null) {
             $parameters = $this->dumpMethodParameters($className, $constructorInjection);
 
-            $str .= sprintf(\PHP_EOL . '    __construct(' . \PHP_EOL . '        %s' . \PHP_EOL . '    )', $parameters);
+            $str .= sprintf("\n" . '    __construct(' . "\n" . '        %s' . "\n" . '    )', $parameters);
         }
 
         return $str;
@@ -77,7 +77,7 @@ private function dumpProperties(ObjectDefinition $definition) : string
             $value = $propertyInjection->getValue();
             $valueStr = $value instanceof Definition ? (string) $value : var_export($value, true);
 
-            $str .= sprintf(\PHP_EOL . '    $%s = %s', $propertyInjection->getPropertyName(), $valueStr);
+            $str .= sprintf("\n" . '    $%s = %s', $propertyInjection->getPropertyName(), $valueStr);
         }
 
         return $str;
@@ -93,7 +93,7 @@ private function dumpMethods(string $className, ObjectDefinition $definition) :
         foreach ($definition->getMethodInjections() as $methodInjection) {
             $parameters = $this->dumpMethodParameters($className, $methodInjection);
 
-            $str .= sprintf(\PHP_EOL . '    %s(' . \PHP_EOL . '        %s' . \PHP_EOL . '    )', $methodInjection->getMethodName(), $parameters);
+            $str .= sprintf("\n" . '    %s(' . "\n" . '        %s' . "\n" . '    )', $methodInjection->getMethodName(), $parameters);
         }
 
         return $str;
@@ -139,6 +139,6 @@ private function dumpMethodParameters(string $className, MethodInjection $method
             $args[] = sprintf('$%s = #UNDEFINED#', $parameter->getName());
         }
 
-        return implode(\PHP_EOL . '        ', $args);
+        return implode("\n" . '        ', $args);
     }
 }
diff --git a/src/Definition/EnvironmentVariableDefinition.php b/src/Definition/EnvironmentVariableDefinition.php
index 5b420967..f82ca413 100644
--- a/src/Definition/EnvironmentVariableDefinition.php
+++ b/src/Definition/EnvironmentVariableDefinition.php
@@ -68,20 +68,20 @@ public function replaceNestedDefinitions(callable $replacer) : void
 
     public function __toString() : string
     {
-        $str = '    variable = ' . $this->variableName . \PHP_EOL
+        $str = '    variable = ' . $this->variableName . "\n"
             . '    optional = ' . ($this->isOptional ? 'yes' : 'no');
 
         if ($this->isOptional) {
             if ($this->defaultValue instanceof Definition) {
                 $nestedDefinition = (string) $this->defaultValue;
-                $defaultValueStr = str_replace(\PHP_EOL, \PHP_EOL . '    ', $nestedDefinition);
+                $defaultValueStr = str_replace("\n", "\n" . '    ', $nestedDefinition);
             } else {
                 $defaultValueStr = var_export($this->defaultValue, true);
             }
 
-            $str .= \PHP_EOL . '    default = ' . $defaultValueStr;
+            $str .= "\n" . '    default = ' . $defaultValueStr;
         }
 
-        return sprintf('Environment variable (' . \PHP_EOL . '%s' . \PHP_EOL . ')', $str);
+        return sprintf('Environment variable (' . "\n" . '%s' . "\n" . ')', $str);
     }
 }
diff --git a/src/Definition/Exception/InvalidDefinition.php b/src/Definition/Exception/InvalidDefinition.php
index f00d93ef..95f95578 100644
--- a/src/Definition/Exception/InvalidDefinition.php
+++ b/src/Definition/Exception/InvalidDefinition.php
@@ -17,7 +17,7 @@ class InvalidDefinition extends \Exception implements ContainerExceptionInterfac
     public static function create(Definition $definition, string $message, \Exception $previous = null) : self
     {
         return new self(sprintf(
-            '%s' . \PHP_EOL . 'Full definition:' . \PHP_EOL . '%s',
+            '%s' . "\n" . 'Full definition:' . "\n" . '%s',
             $message,
             (string) $definition
         ), 0, $previous);
diff --git a/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php b/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
index 7cbb905b..270bad13 100644
--- a/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
+++ b/tests/UnitTest/ServiceLocator/ServiceLocatorTest.php
@@ -4,6 +4,7 @@
 
 namespace DI\Test\UnitTest;
 
+use DI\Container;
 use DI\ContainerBuilder;
 use DI\ServiceLocator;
 use DI\Test\UnitTest\Fixtures\Singleton;
@@ -16,6 +17,8 @@
  */
 class ServiceLocatorTest extends TestCase
 {
+	private ?Container $container;
+
     public function setUp(): void
     {
         $containerBuilder = new ContainerBuilder();