Function assert_array_equals

test/fixtures/wpt/resources/testharness.js:1696–1750

* Assert that ``actual`` and ``expected`` are both arrays, and that the array properties of * ``actual`` and ``expected`` are all the same value (as for :js:func:`assert_equals`). * * @param {Array} actual - Test array. * @param {Array} expected - Array that is expected to contai

(actual, expected, description)

     * @param {string} [description] - Description of the condition being tested.
     */
    function assert_array_equals(actual, expected, description)
    {
        const max_array_length = 20;
        function shorten_array(arr, offset = 0) {
            // Make ", …" only show up when it would likely reduce the length, not accounting for
            // fonts.
            if (arr.length < max_array_length + 2) {
                return arr;
            }
            // By default we want half the elements after the offset and half before
            // But if that takes us past the end of the array, we have more before, and
            // if it takes us before the start we have more after.
            const length_after_offset = Math.floor(max_array_length / 2);
            let upper_bound = Math.min(length_after_offset + offset, arr.length);
            const lower_bound = Math.max(upper_bound - max_array_length, 0);

            if (lower_bound === 0) {
                upper_bound = max_array_length;
            }

            const output = arr.slice(lower_bound, upper_bound);
            if (lower_bound > 0) {
                output.beginEllipsis = true;
            }
            if (upper_bound < arr.length) {
                output.endEllipsis = true;
            }
            return output;
        }

        assert(typeof actual === "object" && actual !== null && "length" in actual,
               "assert_array_equals", description,
               "value is ${actual}, expected array",
               {actual:actual});
        assert(actual.length === expected.length,
               "assert_array_equals", description,
               "lengths differ, expected array ${expected} length ${expectedLength}, got ${actual} length ${actualLength}",
               {expected:shorten_array(expected, expected.length - 1), expectedLength:expected.length,
                actual:shorten_array(actual, actual.length - 1), actualLength:actual.length
               });

        for (var i = 0; i < actual.length; i++) {
            assert(actual.hasOwnProperty(i) === expected.hasOwnProperty(i),
                   "assert_array_equals", description,
                   "expected property ${i} to be ${expected} but was ${actual} (expected array ${arrayExpected} got ${arrayActual})",
                   {i:i, expected:expected.hasOwnProperty(i) ? "present" : "missing",
                    actual:actual.hasOwnProperty(i) ? "present" : "missing",
                    arrayExpected:shorten_array(expected, i), arrayActual:shorten_array(actual, i)});
            assert(same_value(expected[i], actual[i]),
                   "assert_array_equals", description,
                   "expected property ${i} to be ${expected} but got ${actual} (expected array ${arrayExpected} got ${arrayActual})",
                   {i:i, expected:expected[i], actual:actual[i],
                    arrayExpected:shorten_array(expected, i), arrayActual:shorten_array(actual, i)});
        }
    }
    expose_assert(assert_array_equals, "assert_array_equals");

    /**