### Question:
MessageBus implements IOFogModule { @Override public int getModuleIndex() { return MESSAGE_BUS; } private  MessageBus(); @Override int getModuleIndex(); @Override String getModuleName(); static MessageBus getInstance(); synchronized void enableRealTimeReceiving(String receiver); synchronized void disableRealTimeReceiving(String receiver); void update(); void instanceConfigUpdated(); void startServer(); void start(); void stop(); MessagePublisher getPublisher(String publisher); MessageReceiver getReceiver(String receiver); synchronized String getNextId(); synchronized Map<String, Route> getRoutes();  }### Answer:
@Test public void testGetModuleIndex() { assertEquals(Constants.MESSAGE_BUS, messageBus.getModuleIndex()); }