<!DOCTYPE HTML>
<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api/#register-a-custom-property" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
// Tests for error checking during property registration

test(function() {
    assert_throws(new TypeError(), () => CSS.registerProperty());
    assert_throws(new TypeError(), () => CSS.registerProperty(undefined));
    assert_throws(new TypeError(), () => CSS.registerProperty(true));
    assert_throws(new TypeError(), () => CSS.registerProperty(2));
    assert_throws(new TypeError(), () => CSS.registerProperty("css"));
    assert_throws(new TypeError(), () => CSS.registerProperty(null));
}, "registerProperty requires a Dictionary type");

test(function() {
    // Valid property names, shouldn't throw
    CSS.registerProperty({name: '--name1'});
    CSS.registerProperty({name: '--name2, no need for escapes'});
    CSS.registerProperty({name: ['--name', 3]});

    // Invalid property names
    assert_throws(new TypeError(), () => CSS.registerProperty({}));
    assert_throws(new SyntaxError(), () => CSS.registerProperty({name: 'no-leading-dash'}));
    assert_throws(new SyntaxError(), () => CSS.registerProperty({name: ''}));
    assert_throws(new SyntaxError(), () => CSS.registerProperty({name: '\\--name'}));
}, "registerProperty requires a name matching <custom-property-name>");

test(function() {
    CSS.registerProperty({name: '--syntax-test-1', syntax: '*'});
    CSS.registerProperty({name: '--syntax-test-2', syntax: ' * '});
    assert_throws(new SyntaxError(),
        () => CSS.registerProperty({name: '--syntax-test-3', syntax: 'length'}));
}, "registerProperty only allows omitting initialValue is syntax is '*'");

test(function() {
    CSS.registerProperty({name: '--re-register', syntax: '<length>', initialValue: '0px'});
    assert_throws({name: 'InvalidModificationError'},
        () => CSS.registerProperty({name: '--re-register', syntax: '<percentage>', initialValue: '0%'}));
}, "registerProperty fails for an already registered property");
</script>