diff --git a/src/ClassSet.php b/src/ClassSet.php
index d654c1c5..0d748564 100644
--- a/src/ClassSet.php
+++ b/src/ClassSet.php
@@ -11,11 +11,9 @@
  */
 class ClassSet implements \IteratorAggregate
 {
-    /** @var string */
-    private $directory;
+    private string $directory;
 
-    /** @var array */
-    private $exclude;
+    private array $exclude;
 
     private function __construct(string $directory)
     {
@@ -51,7 +49,7 @@ public function getIterator(): \Traversable
             ->ignoreUnreadableDirs(true)
             ->ignoreVCS(true);
 
-        if ($this->exclude) {
+        if ([] !== $this->exclude) {
             $finder->notPath($this->exclude);
         }
 
diff --git a/tests/Integration/CheckEnumTest.php b/tests/Integration/CheckEnumTest.php
new file mode 100644
index 00000000..d0385f5e
--- /dev/null
+++ b/tests/Integration/CheckEnumTest.php
@@ -0,0 +1,107 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Arkitect\Tests\Integration;
+
+use Arkitect\Expression\ForClasses\HaveNameMatching;
+use Arkitect\Expression\ForClasses\IsEnum;
+use Arkitect\Expression\ForClasses\ResideInOneOfTheseNamespaces;
+use Arkitect\Rules\Rule;
+use Arkitect\Tests\Utils\TestRunner;
+use org\bovigo\vfs\vfsStream;
+use PHPUnit\Framework\TestCase;
+
+class CheckEnumTest extends TestCase
+{
+    public function test_naming_is_enforced(): void
+    {
+        $dir = vfsStream::setup('root', null, $this->createDirStructure())->url();
+
+        $runner = TestRunner::create('8.4');
+
+        $rules = [];
+
+        $rules[] = Rule::allClasses()
+            ->that(new ResideInOneOfTheseNamespaces('Modules\*\App\Domains\*\Enums'))
+            ->should(new HaveNameMatching('*Enum'))
+            ->because('we want uniform naming');
+
+        $rules[] = Rule::allClasses()
+            ->that(new ResideInOneOfTheseNamespaces('Modules\*\App\Domains\*\Enums'))
+            ->should(new IsEnum())
+            ->because('Enums should be enums');
+
+        $runner->run($dir, ...$rules);
+
+        $this->assertCount(2, $runner->getViolations());
+        $this->assertCount(0, $runner->getParsingErrors());
+
+        $this->assertStringContainsString('should have a name that matches *Enum because', $runner->getViolations()->get(0)->getError());
+        $this->assertStringContainsString('Aclass should be an enum because Enums should be enums', $runner->getViolations()->get(1)->getError());
+    }
+
+    public function createDirStructure(): array
+    {
+        return [
+            'Modules' => [
+                'Core' => [
+                    'App' => [
+                        'Domains' => [
+                            'Base' => [
+                                'Enums' => [
+                                    'BillingEnum.php' => '<?php
+
+                                    namespace Modules\Core\App\Domains\Base\Enums;
+
+                                    enum BillingEnum {
+                                        case PENDING;
+                                        case PAYED;
+                                    }
+                                    ',
+                                    'GenderEnum.php' => '<?php
+
+                                    namespace Modules\Core\App\Domains\Base\Enums;
+
+                                    enum GenderEnum {
+                                        case MALE;
+                                        case FEMALE;
+                                    }
+                                    ',
+                                    'AClass.php' => '<?php
+
+                                    namespace Modules\Core\App\Domains\Base\Enums;
+
+                                    class Aclass { }
+                                    ',
+                                ],
+                                'Traits' => [
+                                    'OneTrait.php' => '<?php
+
+                                    namespace Modules\Core\App\Domains\Base\Traits;
+
+                                    use Modules\Core\App\Domains\Base\Enums;
+
+                                    trait OneTrait {
+                                        public function one(GenderEnum $gender) {}
+                                    }
+                                    ',
+                                    'TwoTrait.php' => '<?php
+
+                                    namespace Modules\Core\App\Domains\Base\Traits;
+
+                                    use Modules\Core\App\Domains\Base\Enums;
+
+                                    trait TwoTrait {
+                                        public function one(GenderEnum $gender) {}
+                                    }
+                                    ',
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ];
+    }
+}