@Test
public void testPutIn() {

    Liquid empty = new Liquid(0, SimulationConstants.MIN_TEMPERATURE, new Color(0));
    Liquid l1 = new Liquid(pipe.getMaxInput() / 2, SimulationConstants.MIN_TEMPERATURE, new Color(0));
    Liquid l2 = new Liquid(pipe.getMaxInput(), SimulationConstants.MAX_TEMPERATURE, new Color(2));
    assertEquals(empty, pipe.putIn(l1));
    assertEquals(empty, pipe.putIn(l2));
    assertEquals(empty, pipe.putIn(l1));
    assertEquals(empty, pipe.putIn(l1));
    assertEquals(empty, pipe.putIn(l2));
    assertEquals(l1, pipe.putIn(l2));
    assertEquals(l2, pipe.putIn(l2));
    assertEquals(l1, pipe.putIn(l2));
    assertEquals(l1, pipe.putIn(l2));
}