map.keys()], ["b", "a"]);
        assert_array_equals([...map.values()].map(v => v.idlType), ["long", "DOMString"]);
    }, 'should return a properly ordered map that contains IDL types of valid attributes for inherited interfaces');

    test(function() {
        var context = new IdlArray();
        context.add_idls("interface A : B { attribute DOMString a; };");
        context.add_idls("interface B { [Default] object toJSON(); attribute long b; };");
        var map = context.members.A.default_to_json_o