css/cssom-view/window-scroll-arguments.html

<!DOCTYPE HTML>
<title>Window.scroll* methods exception handling with various arguments</title>
<link rel="help"
  href="https://drafts.csswg.org/cssom-view/#extensions-to-the-window-interface">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<!--
  This test makes sure that calling the window scrolling methods with a single
  non-dictionary argument or with a dictionary whose 'behavior' field is invalid
  throws an exception.
-->
<div style="height: 1000px; width: 1000px;"></div>

<script type="text/javascript">
  "use strict";

  const x = 25;
  const y = 50;

  function reset() {
    window.scrollTo(0, 0);
  }

  let scroll_methods = [window.scrollTo, window.scroll, window.scrollBy];

  for (const scroll_method of scroll_methods) {
    promise_test(async (test) => {
      reset();
      try {
        await scroll_method();
      } catch(e) {
        assert_unreached(e);
      }
    }, scroll_method.name + " with 0 arguments");

    promise_test(async (test) => {
      reset();
      await promise_rejects_js(test, TypeError, scroll_method(x));
    }, scroll_method.name + " with 1 non-dictionary argument");

    promise_test(async (test) => {
      reset();
      try {
        await scroll_method({ });
        await scroll_method({ left: x });
        await scroll_method({ top: y });
        await scroll_method({ behavior: "auto" });
        await scroll_method({ behavior: "instant" });
        await scroll_method({ behavior: "smooth" });
        await scroll_method({ left: x, top: y });
        await scroll_method({ left: x, top: y, behavior: "auto" });
        await scroll_method({ left: x, top: y, behavior: "instant" });
        await scroll_method({ left: x, top: y, behavior: "smooth" });
      } catch(e) {
        assert_unreached(e);
      }
    }, scroll_method.name + " with a valid ScrollToOptions argument");

    promise_test(async (test) => {
      reset();
      await promise_rejects_js(test, TypeError, scroll_method({ behavior: "" }));
      await promise_rejects_js(test, TypeError, scroll_method({ left: x, top: y, behavior: "abcd" }));
      await promise_rejects_js(test, TypeError, scroll_method({ left: x, top: y, behavior: 200 }));
    }, scroll_method.name + " with an invalid ScrollToOptions argument");
  }
</script>