diff --git a/packages/test-utils/types/index.d.ts b/packages/test-utils/types/index.d.ts
index ed8d0c502..48d1a4d90 100644
--- a/packages/test-utils/types/index.d.ts
+++ b/packages/test-utils/types/index.d.ts
@@ -56,7 +56,7 @@ interface BaseWrapper {
   visible (): boolean
 
   attributes(): { [name: string]: string }
-  classes(): Array<string> | void
+  classes(): Array<string>
   props(): { [name: string]: any }
 
   hasAttribute (attribute: string, value: string): boolean