auro-back-to-top: figure out how to test scroll behavior in OpenWC

[jason-capsule42]

User story

We need to figure out how to test scroll behavior within our automation testing framework and apply that to testing the UX of backtoptop

Outline subtasks or tasks

List specific steps required to deliver this work.

• learn how to test scrolling behavior in OpenWC
• create test cases covering the scrolling behavior of auro-backtoptop

Additional context

Due to low testing, the threshold was lowered. Once this update is complete, this should be updated to 80%

• a6637f4

[fajar-apri-alaska]

Hi team.
If I may, I have done some research for this issue.

it('tests scroll-related events', async () => {
    window.innerHeight = 2500;
    const el = await fixture(html`
      <auro-backtotop cssclass="testClass"></auro-backtotop>
    `);

    simulateScroll(0, 500);
    expect(el.hidden).to.be.false;

    simulateScroll(0, 0);
    expect(el.hidden).to.be.true;
  });

function simulateScroll(x, y) {
    const scrollEvent = new CustomEvent('scroll', { detail: { x, y } });
    window.scrollX = x;
    window.scrollY = y;
    document.dispatchEvent(scrollEvent);
  }

I have also added the rest for 100% achievement.

[blackfalcon]

Thanks @fajar-apri-alaska. If you want to submit a PR on this, I will assign the issue to you.