diff --git a/types/underscore.string/underscore.string-tests.ts b/types/underscore.string/underscore.string-tests.ts
index 545f6362d6..5b827cd880 100644
--- a/types/underscore.string/underscore.string-tests.ts
+++ b/types/underscore.string/underscore.string-tests.ts
@@ -52,6 +52,7 @@ _.succ('A');
 _.titleize('my name is epeli');
 
 _.camelize('-moz-transform');
+_.camelize('-moz-transform', true);
 
 _.classify('some_class_name');