create animation frame test helper

Author: keithamus

test/lazy-define.ts

@@ -2,14 +2,16 @@ import {expect, fixture, html} from '@open-wc/testing'
 import {spy} from 'sinon'
 import {lazyDefine} from '../src/lazy-define.js'
 
+const animationFrame = () => new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+
 describe('lazyDefine', () => {
   describe('ready strategy', () => {
     it('calls define for a lazy component', async () => {
       const onDefine = spy()
       lazyDefine('scan-document-test', onDefine)
       await fixture(html`<scan-document-test></scan-document-test>`)
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
 
       expect(onDefine).to.be.callCount(1)
     })
@@ -19,7 +21,7 @@ describe('lazyDefine', () => {
       await fixture(html`<later-defined-element-test></later-defined-element-test>`)
       lazyDefine('later-defined-element-test', onDefine)
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
 
       expect(onDefine).to.be.callCount(1)
     })
@@ -39,7 +41,7 @@ describe('lazyDefine', () => {
         <twice-defined-element></twice-defined-element>
       `)
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
 
       expect(onDefine).to.be.callCount(2)
     })
@@ -51,12 +53,12 @@ describe('lazyDefine', () => {
       lazyDefine('scan-document-test', onDefine)
       await fixture(html`<scan-document-test data-load-on="firstInteraction"></scan-document-test>`)
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
       expect(onDefine).to.be.callCount(0)
 
       document.dispatchEvent(new Event('mousedown'))
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
       expect(onDefine).to.be.callCount(1)
     })
   })
@@ -68,12 +70,12 @@ describe('lazyDefine', () => {
         html`<div style="height: calc(100vh + 256px)"></div>
           <scan-document-test data-load-on="visible"></scan-document-test>`
       )
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
       expect(onDefine).to.be.callCount(0)
 
       document.documentElement.scrollTo({top: 10})
 
-      await new Promise<unknown>(resolve => requestAnimationFrame(resolve))
+      await animationFrame()
       expect(onDefine).to.be.callCount(1)
     })
   })