Tests don't ensure specific interval between commands

e.g.
```
    assert [c.args[0] for c in mock_socket.sendto.mock_calls] == [
        b"PANEL_LIGHTING 1\n",
        b"DASHBOARD_LIGHTING 3276\n",
        b"TV_ON_OFF 1\n",
    ]
    assert [c.args[0] for c in mock_sleep.mock_calls] == [0.3, 0.3, 0.8, 0.3]
```
doesn't ensure `DASHBOARD_LIGHTING` is 0.3 seconds later than `PANEL_LIGHTING`