    @Test
    public void nextMicrophoneState() {

        assertEquals(MicrophoneState.BLOCKED, stateMachine.getMicrophoneState());
        stateMachine.nextMicrophoneState();
        assertEquals(MicrophoneState.NO_SOUND, stateMachine.getMicrophoneState());
        stateMachine.nextMicrophoneState();
        assertEquals(MicrophoneState.NEUTRAL_SOUND, stateMachine.getMicrophoneState());
        stateMachine.nextMicrophoneState();
    }