als.states.delete('--foo') });
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_true(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector only applies on given ident");

    test(function(t) {
        myCE.elementInternals.states.add('--foo');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--foo') });
        assert_false(myCE.elementInternals.states.h