diff --git a/tests/mocks/autoloader.php b/tests/mocks/autoloader.php
index 1fcba78..be1c222 100644
--- a/tests/mocks/autoloader.php
+++ b/tests/mocks/autoloader.php
@@ -87,7 +87,7 @@
 			return FALSE;
 		}
 
-		throw new InvalidArgumentException("Unable to load $class.");
+		throw new InvalidArgumentException("Unable to load {$class}.");
 	}
 
 	include_once($file);