@Test
    public void itSetsBoilerState() {
        maker.setBoilerState(CoffeeMakerAPI.BOILER_ON);
        assertEquals(CoffeeMakerAPI.BOILER_ON, maker.getBoilerState());

        maker.setBoilerState(CoffeeMakerAPI.BOILER_OFF);
        assertEquals(CoffeeMakerAPI.BOILER_OFF, maker.getBoilerState());
    }