How can I call a private method contained into a class that implements an interface, in a junit test?

Question

edit: I apologize if the post has been considered too confusing, i'll edit it and leave only the parts regarding my problem...

I have written a class named "ArithmeticNode" which implements an interface containing the following methods:

public void turnOn() {
  arithmeticServer.start();
} 

public void turnOff(){
  arithmeticServer.stop();
}

and contains also a private method:

private void negotiatePort(NodeManifest nodeManifest, ThriftServer arithmeticServer) {
    while(true) {
        int proposedPort = arithmeticServer.start();
        int returnedPort = managementClient.registerNode(nodeManifest, proposedPort);
        if(proposedPOrt != returnedPort) {
            arithnemticServer.stop();
        }
        else
            break;
    }
}

What I'm trying to do is to write a test in which I create a number of these arithmetic nodes and make them register to a management node that I've already written and use as server. Then there will be a second part of my project where I'll make those nodes interact, but that's not part of the actual problem. I have already written a working junit test:

@Test
public void testArithmeticServer() throws Exception {

    List<NodeManifest> nodeManifests = new ArrayList<>();
    nodeManifests.add(new NodeManifest("localhost", Arrays.asList(new String[]{"addition"})));
    nodeManifests.add(new NodeManifest("localhost", Arrays.asList(new String[]{"subtraction","multiplication"})));
    nodeManifests.add(new NodeManifest("localhost", Arrays.asList(new String[]{"addition","multiplication","division"})));
    nodeManifests.add(new NodeManifest("localhost", Arrays.asList(new String[]{"addition","division"})));

    List<ThriftServer> arithmeticServers = new ArrayList<>();

    for (NodeManifest nodeManifest : nodeManifests) {
        ThriftServer arithmeticServer = new ThriftServer(ArithmeticServiceHandler.class);
        arithmeticServers.add(arithmeticServer);
        negotiatePort(nodeManifest,arithmeticServer);
    }


    private void negotiatePort() {
        while(true) {
        int proposedPort = arithmeticServer.start();
        int returnedPort = managementClient.registerNode(nodeManifest, proposedPort);
        if(proposedPOrt != returnedPort) {
            arithnemticServer.stop();
        }
        else
            break;
    }
}

I need to write a test where i don't have to put the negotiatePort method directly inside the test code, but I call for each node the private negotiatePort method I have inside my arithmeticNode class; I'm not sure if it's possible to do that and how. I hope I've been less confusing than the previous version of the post :-)

Answer 1

You can make the negotiatePort method package local. Then you would be able to call it within your test (which should reside in the same package). And nobody outside the package would be able to use it