test: fix demo snapshot

test/index.ts

@@ -1,14 +1,5 @@
-import Vue from 'vue';
-import { mount, TransitionStub } from '@vue/test-utils';
-
-// prevent vue warning log
-Vue.config.silent = true;
-
-// stub transition
-Vue.component('transition', TransitionStub as any);
-
 // promisify setTimeout
-export function later(delay: number = 0): Promise<void> {
+export function later(delay = 0): Promise<void> {
   return new Promise((resolve) => {
     setTimeout(resolve, delay);
   });
@@ -16,4 +7,4 @@ export function later(delay: number = 0): Promise<void> {
 
 export * from './dom';
 export * from './event';
-export { mount };
+export { mount } from '@vue/test-utils';