diff --git a/composer.json b/composer.json
index f6ca9ec..e75f3c2 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,8 @@
     },
     "require": {
         "php": "^8.1",
-        "doctrine/coding-standard": "^11.0"
+        "doctrine/coding-standard": "^11.0",
+        "slevomat/coding-standard": "^8.9.2"
     },
     "require-dev": {
         "phpstan/extension-installer": "^1.2",
diff --git a/tests/TestCase.php b/tests/TestCase.php
index e632c52..126da5f 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -6,6 +6,8 @@
 
 use SlevomatCodingStandard\Sniffs\TestCase as SlevomatTestCase;
 
+use function assert;
+use function class_exists;
 use function str_replace;
 use function strlen;
 use function substr;
@@ -14,6 +16,9 @@ abstract class TestCase extends SlevomatTestCase
 {
     protected static function getSniffClassName(): string
     {
-        return str_replace('\\Tests\\', '\\', substr(static::class, 0, -strlen('Test')));
+        $class = str_replace('\\Tests\\', '\\', substr(static::class, 0, -strlen('Test')));
+        assert(class_exists($class));
+
+        return $class;
     }
 }