Fix the issue.

Author: ghengeveld

src/hello.spec.js

@@ -1,5 +1,8 @@
 import React from "react"
 import { render } from "@testing-library/react"
+import { act } from "react-dom/test-utils"
+
+act(() => ({ then: () => {} })).then(() => {})
 
 const Hello = () => {
   const promise = Promise.reject("Oh no!")