<!DOCTYPE html>
<body>
<script src="../resources/js-test-pre.js"></script>
<script>
    description("Streams should not directly use array public APIs");
    jsTestIsAsync = true;

    const ArrayPushBackup = Array.prototype.push;
    const ArrayShiftBackup = Array.prototype.shift;

    Array.prototype.push = function() {
        testFailed("Array.prototype.push called");
    }

    Array.prototype.shift = function() {
        testFailed("Array.prototype.shift called");
    }

    function cleanAndFinishTest() {
        Array.prototype.push = ArrayPushBackup;
        Array.prototype.shift = ArrayShiftBackup;
        finishJSTest();
    }

    try {
        let _controller;
        const reader = new ReadableStream({
            start: function(controller) {
                _controller = controller;
            }
        }).getReader();

        // checking whether pushing/shifting pending read promises is shielded.
        const readPromise = reader.read().then(function(_result) {
            result = _result;
            shouldBeEqualToString("result.value", "half baked potato");
            // checking whether pushing/shifting enqueued values is shielded.
            _controller.enqueue("fully baked potato");
            return reader.read().then(function(_result) {
                result = _result;
                shouldBeEqualToString("result.value", "fully baked potato");
                cleanAndFinishTest();
            }, cleanAndFinishTest);
        }, cleanAndFinishTest);
        _controller.enqueue("half baked potato");
    } catch (error) {
        testFailed("Exception thrown: " + error);
        cleanAndFinishTest();
    }
</script>
<script src="../resources/js-test-post.js"></script>
</body>