chromium/third_party/blink/web_tests/external/wpt/css/selectors/focus-visible-028.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8" />
  <title>CSS Test (Selectors): Programmatic focus causes :focus-visible to match after keyboard usage when preventDefault() is used</title>
  <link rel="author" title="Tyler Jones" href="[email protected]" />
  <link rel="help" href="https://drafts.csswg.org/selectors-4/#the-focus-visible-pseudo" />
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="/resources/testdriver.js"></script>
  <script src="/resources/testdriver-vendor.js"></script>
  <style>
    @supports not selector(:focus-visible) {
      :focus {
        outline: red solid 5px;
        background-color: red;
      }
    }

    :focus-visible {
      outline: blue solid 5px;
    }

    :focus:not(:focus-visible) {
      outline: 0;
      background-color: lime;
    }
  </style>
</head>
<body>
  This test checks that programmatically focusing an element after a click and using keyboard afterwards triggers <code>:focus-visible</code> matching.
  <ol id="instructions">
    <li>If the user-agent does not claim to support the <code>:focus-visible</code> pseudo-class then SKIP this test.</li>
    <li>Click the button below that says "Click me".</li>
    <li>Once focused on the button that says "I will be focused programmatically", use "Left" or "Right" arrow keys to navigate through the button group</li>
    <li>If any button within the group has a blue outline after using either arrow key, then the test result is SUCCESS. If the element has a green background after using either arrow key, then the test result is FAILURE.</li>
  </ol>
  <br />
  <button id="button">Click me</button>
  <div id="container">
      <button id="btn1">I will be focused programmatically.</button>
      <button id="btn2">Button 2</button>
      <button id="btn3">Button 3</button>
  </div>
  <script>
    button.addEventListener("click", () => {
      btn1.focus();
    });

    focusTrap(document.querySelector('#container'));

    function focusTrap(container) {
      container.addEventListener('keydown', (e) => {
        if (e.key !== 'ArrowRight' && e.key !== 'ArrowLeft') return;
        e.preventDefault();

        const btns = container.querySelectorAll('button');
        const currentIndex = Array.from(btns).indexOf(document.activeElement);
        let nextIndex;

        if (e.key === 'ArrowRight') {
          nextIndex = (currentIndex + 1) % btns.length;
        } else if (e.key === 'ArrowLeft') {
          nextIndex = (currentIndex - 1 + btns.length) % btns.length;
        }

        btns[nextIndex].focus();
      });
    }

    promise_test(async t => {
      const arrow_right = "\uE014";
      btn2.addEventListener("focus", t.step_func_done((e) => {
        assert_equals(getComputedStyle(btn2).outlineColor, "rgb(0, 0, 255)", `outlineColor for ${btn2.tagName}#${btn2.id} is blue`);
        assert_not_equals(getComputedStyle(btn2).backgroundColor, "rgb(0, 255, 0)", `backgroundColor for ${btn2.tagName}#${btn2.id} is NOT lime`);
      }));

      await test_driver.click(button);
      assert_equals(document.activeElement, btn1);
      await test_driver.send_keys(btn1, arrow_right);
    }, "Programmatic focus after click and keyboard interaction should match :focus-visible");
  </script>
</body>
</html>