@Test
public void testIsLiquidEntering() {

    assertFalse(pipe.isLiquidEntering());
    pipe.putIn(new Liquid(pipe.getMaxInput(), SimulationConstants.MIN_TEMPERATURE, new Color(0)));
    assertTrue(pipe.isLiquidEntering());
    pipe.putIn(new Liquid(0, SimulationConstants.MIN_TEMPERATURE, new Color(0)));
    assertFalse(pipe.isLiquidEntering());
}