Introduce ClassNotFoundException for container

src/Container/ClassNotFoundException.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Ardent\Undercurrent\Container;
+
+use Exception;
+
+class ClassNotFoundException extends Exception
+{
+    public function __construct(string $className)
+    {
+        parent::__construct(sprintf(
+            'Class %s not found in container',
+            $className
+        ));
+    }
+}

src/Container/GenericContainer.php

@@ -43,7 +43,7 @@ class GenericContainer implements ContainerInterface
             $className = $this->aliases[$className];
         }
         if (!isset($this->definitions[$className])) {
-            throw new Exception("Class $className not found in container");
+            throw new ClassNotFoundException($className);
         }
 
         $definition = $this->definitions[$className]['definition'];