HarmonyOS 鸿蒙Next基于ArkTS测试示例运行报错 Error in testUiExample, Can not connect to AAMS 是什么原因？

HarmonyOS 鸿蒙Next基于ArkTS测试示例运行报错 Error in testUiExample, Can not connect to AAMS 是什么原因？

按照https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkxtest-guidelines-V5 文档提供的示例：

import { describe, it, expect } from '@ohos/hypium';

// 导入测试依赖kit
import { abilityDelegatorRegistry, Driver, ON } from '@kit.TestKit';
import { UIAbility, Want } from '@kit.AbilityKit';

const delegator: abilityDelegatorRegistry.AbilityDelegator = abilityDelegatorRegistry.getAbilityDelegator()
const bundleName = abilityDelegatorRegistry.getArguments().bundleName;

function sleep(time: number) {
  return new Promise<void>((resolve: Function) => setTimeout(resolve, time));
}

export default function abilityTest() {
  describe('ActsAbilityTest', () => {
    it('testUiExample',0, async (done: Function) => {
      console.info("uitest: TestUiExample begin");
      //start tested ability
      const want: Want = {
        bundleName: bundleName,
        abilityName: 'EntryAbility'
      }
      await delegator.startAbility(want);
      await sleep(1000);
      //check top display ability
      await delegator.getCurrentTopAbility().then((Ability: UIAbility)=>{
        console.info("get top ability");
        expect(Ability.context.abilityInfo.name).assertEqual('EntryAbility');
      })
      //ui test code
      //init driver
      let driver = Driver.create();
      await driver.delayMs(1000);
      //find button on text 'Next'
      let button = await driver.findComponent(ON.text('Next'));
      //click button
      await button.click();
      await driver.delayMs(1000);
      //check text
      await driver.assertComponentExist(ON.text('after click'));
      await driver.pressBack();
      done();
    })
  })
}

操作到 执行测试脚本报错提示：

07/01 10:31:48:391: Launching com.example.uitest
Testing started at 10:31 ...
$hdc uninstall com.example.uitest
$hdc install D:\DevEcoStudioProjects\UiTest\entry\build\default\outputs\default\entry-default-unsigned.hap
$hdc install D:\DevEcoStudioProjects\UiTest\entry\build\default\outputs\ohosTest\entry-ohosTest-unsigned.hap
Running tests.
$hdc shell aa test -b com.example.uitest -m entry_test -s unittest OpenHarmonyTestRunner -s class ActsAbilityTest -s timeout 15000
07/01 10:32:01:635: Launch com.example.uitest success in 13 s 244 ms
Error in testUiExample, Can not connect to AAMS at anonymous (entrycosTest/ets/test/Ability.test.ets:29:20)

麻烦大佬帮看下这个问题是什么原因导致的~