gecko-dev/testing/web-platform/tests/encoding/textdecoder-utf16-surrogates.any.js

// META: title=Encoding API: UTF-16 surrogate handling

var bad = [
    {
        encoding: 'utf-16le',
        input: [0x00, 0xd8],
        expected: '\uFFFD',
        name: 'lone surrogate lead'
    },
    {
        encoding: 'utf-16le',
        input: [0x00, 0xdc],
        expected: '\uFFFD',
        name: 'lone surrogate trail'
    },
    {
        encoding: 'utf-16le',
        input: [0x00, 0xd8, 0x00, 0x00],
        expected: '\uFFFD\u0000',
        name: 'unmatched surrogate lead'
    },
    {
        encoding: 'utf-16le',
        input: [0x00, 0xdc, 0x00, 0x00],
        expected: '\uFFFD\u0000',
        name: 'unmatched surrogate trail'
    },
    {
        encoding: 'utf-16le',
        input: [0x00, 0xdc, 0x00, 0xd8],
        expected: '\uFFFD\uFFFD',
        name: 'swapped surrogate pair'
    }
];

bad.forEach(function(t) {
    test(function() {
        assert_equals(new TextDecoder(t.encoding).decode(new Uint8Array(t.input)), t.expected);
    }, t.encoding + ' - ' + t.name);
    test(function() {
        assert_throws(new TypeError(), function() {
            new TextDecoder(t.encoding, {fatal: true}).decode(new Uint8Array(t.input))
        });
    }, t.encoding + ' - ' + t.name + ' (fatal flag set)');
});