<!DOCTYPE html>
<title>Tests which properties are allowed in @fallback-position</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#fallback-rule">
<link rel="author" href="mailto:xiaochengh@chromium.org">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style id="style"></style>
<script>
function cleanup() {
  while (style.sheet.cssRules.length)
    style.sheet.deleteRule(0);
}

function test_allowed_declaration(property, value = '1px') {
  test(t => {
    t.add_cleanup(cleanup);
    const serialization = `${property}: ${value}`;
    const rule = `@position-fallback --foo { @try { ${property}: ${value}; } }`;
    const index = style.sheet.insertRule(rule);
    const parsed = style.sheet.cssRules[index].cssRules[0];
    assert_equals(parsed.cssText, `@try { ${serialization}; }`);
  }, `${property}: ${value} is allowed in @fallback-position`);
}

function test_disallowed_declaration(property, value = '1px') {
  test(t => {
    t.add_cleanup(cleanup);
    const rule = `@position-fallback --foo { @try { ${property}: ${value}; } }`;
    const index = style.sheet.insertRule(rule);
    const parsed = style.sheet.cssRules[index].cssRules[0];
    assert_equals(parsed.cssText, `@try { }`);
  }, `${property}: ${value} is disallowed in @fallback-position`);
}

// Inset properties are allowed
test_allowed_declaration('top');
test_allowed_declaration('bottom');
test_allowed_declaration('left');
test_allowed_declaration('right');
test_allowed_declaration('inset-block-start');
test_allowed_declaration('inset-block-end');
test_allowed_declaration('inset-inline-start');
test_allowed_declaration('inset-inline-end');
test_allowed_declaration('inset-block');
test_allowed_declaration('inset-inline');
test_allowed_declaration('inset');

// Sizing properties are allowed
test_allowed_declaration('width');
test_allowed_declaration('height');
test_allowed_declaration('block-size');
test_allowed_declaration('inline-size');
test_allowed_declaration('min-width');
test_allowed_declaration('min-height');
test_allowed_declaration('min-block-size');
test_allowed_declaration('min-inline-size');
test_allowed_declaration('max-width');
test_allowed_declaration('max-height');
test_allowed_declaration('max-block-size');
test_allowed_declaration('max-inline-size');

// Box alignment properties are allowed
test_allowed_declaration('justify-content', 'normal');
test_allowed_declaration('align-content', 'normal');
test_allowed_declaration('justify-items', 'normal');
test_allowed_declaration('align-items', 'normal');
test_allowed_declaration('justify-self', 'normal');
test_allowed_declaration('align-self', 'normal');

// Custom properties are disallowed
test_disallowed_declaration('--custom');

// Margin properties are disallowed
test_disallowed_declaration('margin-left');
test_disallowed_declaration('margin-right');
test_disallowed_declaration('margin-top');
test_disallowed_declaration('margin-bottom');
test_disallowed_declaration('margin');

// Test some other disallowed properties
test_disallowed_declaration('font-size');
test_disallowed_declaration('border-width');
test_disallowed_declaration('padding');
test_disallowed_declaration('display');
test_disallowed_declaration('position');
test_disallowed_declaration('float');

// 'revert' and 'revert-layer' are disallowed
test_disallowed_declaration('top', 'revert');
test_disallowed_declaration('top', 'revert-layer');
test_disallowed_declaration('inset', 'revert');
test_disallowed_declaration('inset', 'revert-layer');

// !important is disallowed
test_disallowed_declaration('top', '1px !important');
test_disallowed_declaration('inset', '1px !important');
</script>
