diff --git a/lib/extensions.js b/lib/extensions.js
index <HASH>..<HASH> 100644
--- a/lib/extensions.js
+++ b/lib/extensions.js
@@ -17,7 +17,9 @@ Chai.Assertion.addMethod("class", function(classNames){
 			classList.contains(name),
 			"expected classList '" + subject.className + "' to include #{exp}",
 			"expected classList '" + subject.className + "' not to include #{exp}",
-			name
+			subject.className,
+			name,
+			false
 		);
 	}
 });
Avoid printing "HTMLSpanElement" in failed class-matches