@Test public void connectionTest() { CircularBumper circularBumper = new CircularBumper(100, 100, 0, "cBump"); Flipper flipper = new Flipper(200, 200, true, "f1"); assertEquals(model.getConnections(), new ArrayList<Connection>()); model.addConnection(circularBumper, flipper); assertTrue(model.getConnections().size() == 1); model.addConnection(circularBumper, flipper); assertTrue(model.getConnections().size() == 1); }