css/css-scoping/host-parsing.html

<!DOCTYPE html>
<title>Test parsing of the :host/host() pseudo-classes</title>
<link rel="help" href="https://drafts.csswg.org/css-scoping/#selectordef-host-function">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/support/parsing-testcommon.js"></script>
<script>
  test_valid_selector(':host');
  test_valid_selector(':host(.a)');
  test_valid_selector(':host(div.a)');

  test_invalid_selector(':host()');
  test_invalid_selector(':host(.a, .b)');
  test_invalid_selector(':host(.a + .b)');
  test_invalid_selector(':host(.a + .b, #c > #d)');
</script>