test: update test case

src/Image.tsx

@@ -13,6 +13,7 @@ import type { ImageElementProps } from './interface';
 import type { PreviewProps, ToolbarRenderInfoType } from './Preview';
 import Preview from './Preview';
 import PreviewGroup from './PreviewGroup';
+import { isImageValid } from './util';
 
 export interface ImagePreviewType
   extends Omit<
@@ -66,15 +67,6 @@ interface CompoundedComponent<P> extends React.FC<P> {
 
 type ImageStatus = 'normal' | 'error' | 'loading';
 
-function isImageValid(src) {
-  return new Promise(resolve => {
-    const img = document.createElement('img');
-    img.onerror = () => resolve(false);
-    img.onload = () => resolve(true);
-    img.src = src;
-  });
-}
-
 const ImageInternal: CompoundedComponent<ImageProps> = props => {
   const {
     src: imgSrc,

src/util.ts

@@ -0,0 +1,8 @@
+export function isImageValid(src: string) {
+  return new Promise(resolve => {
+    const img = document.createElement('img');
+    img.onerror = () => resolve(false);
+    img.onload = () => resolve(true);
+    img.src = src;
+  });
+}

tests/fallback.test.tsx

@@ -1,7 +1,16 @@
+import { act, fireEvent, render } from '@testing-library/react';
 import React from 'react';
-import { render, fireEvent, act } from '@testing-library/react';
 import Image from '../src';
 
+jest.mock('../src/util', () => {
+  const { isImageValid, ...rest } = jest.requireActual('../src/util');
+
+  return {
+    ...rest,
+    isImageValid: () => Promise.resolve(false),
+  };
+});
+
 describe('Fallback', () => {
   beforeEach(() => {
     jest.useFakeTimers();
@@ -13,19 +22,15 @@ describe('Fallback', () => {
 
   const fallback = 'https://zos.alipayobjects.com/rmsportal/jkjgkEfvpUPVyRjUImniVslZfWPnJuuZ.png';
 
-  it('Fallback correct', () => {
+  it('Fallback correct', async () => {
     const { container } = render(<Image src="abc" fallback={fallback} />);
 
-    act(() => {
-      jest.runAllTimers();
-    });
-
-    fireEvent.click(container.querySelector('.rc-image'));
-    act(() => {
+    await act(async () => {
       jest.runAllTimers();
+      await Promise.resolve();
     });
 
-    expect(container.querySelector('.rc-image-preview')).toBeFalsy();
+    expect(container.querySelector('img').src).toEqual(fallback);
   });
 
   it('should not show preview', () => {