css/mediaqueries/forced-colors.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/mediaqueries-5/#forced-colors" />
<script type="text/javascript" src="/resources/testharness.js"></script>
<script type="text/javascript" src="/resources/testharnessreport.js"></script>

<script type="text/javascript" src="resources/matchmedia-utils.js"></script>
<script>
query_should_be_known("(forced-colors)");
query_should_be_known("(forced-colors: none)");
query_should_be_known("(forced-colors: active)");

query_should_be_unknown("(forced-colors: 0)");
query_should_be_unknown("(forced-colors: no-preference)");
query_should_be_unknown("(forced-colors: 10px)");
query_should_be_unknown("(forced-colors: active 0)");
query_should_be_unknown("(forced-colors: none active)");
query_should_be_unknown("(forced-colors: active/none)");

test(() => {
  let booleanContext = window.matchMedia("(forced-colors)");
  let none = window.matchMedia("(forced-colors: none)");
  assert_equals(booleanContext.matches, !none.matches);
}, "Check that none evaluates to false in the boolean context");
</script>