webstorage/storage_in.window.js

["localStorage", "sessionStorage"].forEach(function(name) {
    test(function() {
        var storage = window[name];
        storage.clear();

        assert_false("name" in storage);
        storage["name"] = "user1";
        assert_true("name" in storage);
    }, "The in operator in " + name + ": property access");

    test(function() {
        var storage = window[name];
        storage.clear();

        assert_false("name" in storage);
        storage.setItem("name", "user1");
        assert_true("name" in storage);
        assert_equals(storage.name, "user1");
        storage.removeItem("name");
        assert_false("name" in storage);
    }, "The in operator in " + name + ": method access");
});