input-events-spin-button-click-on-number-input.html

<!DOCTYPE html>
<html>
<head>
<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>
</head>
<body>
<input type="number" id="number_input">
<script>
promise_test(async function() {
  const inputElement = document.getElementById("number_input");
  let events = [];
  inputElement.addEventListener("beforeinput", () => {
    events.push("beforeinput");
  });
  inputElement.addEventListener("input", () => {
    events.push("input");
  });
  inputElement.addEventListener("change", () => {
    events.push("change");
  });

  inputElement.focus();
  // Get the spin button up arrow key location
  const x1 = (inputElement.offsetLeft + inputElement.offsetWidth - 10);
  const y1 = (inputElement.offsetTop + inputElement.offsetHeight / 4);
  await test_driver_internal.click(inputElement,{x: x1, y: y1});
  assert_array_equals(events, ['beforeinput','input','change']);
}, "Number input should fire beforeinput event before the input and change event");
</script>
</body>
</html>

chromium/third_party/blink/web_tests/external/wpt/input-events/input-events-spin-button-click-on-number-input.html