Mockito:How to mock method called inside another method

Question

I am new to mockito and I am using mockito to test method which is calling another method and called method returns string. I tried but I am unable write test. Please help

public class MyClass {
  protected String processIncominData(String input) {
    String request = ...;
    ...
    String response = forwardRequest(request);
    ...
    return response;
  }

  public String forwardRequest(String requestToSocket) {
   String hostname = socketServerName;
    int port = socketServerPort;
    String responseLine=null;
    Socket clientSocket = null;  
    PrintStream outs=null;

    BufferedReader is = null;
    BufferedWriter bwriter=null;

    try {
        clientSocket = new Socket(hostname, port);
        outs=new PrintStream(clientSocket.getOutputStream());
        is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        bwriter = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));

    } catch (UnknownHostException e) {
        LOGGER.error("Don't know about host: " + hostname + e.getMessage());
    } catch (IOException e) {
        LOGGER.error("Couldn't get I/O for the connection to: " + hostname + e.getMessage());
    }

    if (clientSocket == null || outs == null || is == null) {
        LOGGER.error("Something is wrong. One variable is null.");
    }
    try {
        while ( true ) {
            StringBuilder sb = new StringBuilder();
            sb.append(requestToSocket);

            String  request = sb.toString().trim();
            bwriter.write(request);
            bwriter.write("\r\n");
            bwriter.flush();
            responseLine = is.readLine();
            LOGGER.info("Socket returns : " + responseLine);
            //outs.println(responseLine);
            bwriter.close();
        }
    } catch (UnknownHostException e) {
        LOGGER.error("Trying to connect to unknown host: "+ e.getMessage());
    } catch (IOException e) {
        LOGGER.error("IOException:  "+ e.getMessage());
    }
    finally{
        try {
            outs.close();
            is.close();
            clientSocket.close(); 
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    return responseLine;
  }
}

I want to mock xml response here to test processIncomingData method..This response is coming from socket server and I am sending request by socket client. I think socket will not matter if I can mock xmlResponse from socket. Please give any helpful answer

Show how xmlResponse is being generated. You need to use a mock at the line String xmlResponse = ...;. If this is an instance method call, use Mockito to mock the bean (read socket client). If this is a static call, use JMockit to mock the static call. — John B
– John B, Commented Nov 25, 2014 at 12:42
I am reading xml response from socket server. It is in string format like "<response><test>123</test></response>" etc — Lakshya
– Lakshya, Commented Nov 25, 2014 at 13:17
Your unit test should not depend on a socket server. You should be mocking the client. — John B
– John B, Commented Nov 25, 2014 at 13:28
Post more code. Specifically, 1) the full line of code that retrieves xmlResponse 2) how MyClass gets the instance of the client it is using. — John B
– John B, Commented Nov 25, 2014 at 13:33

AntoineB · Accepted Answer · 2018-07-12 12:17:29Z

3

You can try the spy method:

MyClass myClass = spy(new MyClass());
when(myClass.forwardRequest("foo")).thenReturn("bar");

then when you call

myClass.processIncominData("baz");

the response will be "bar" (if request is "foo")

PS: When you need to mock class under test it shows some problem with your design.

edited Jul 12, 2018 at 12:17

AntoineB

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answered Nov 25, 2014 at 12:35

talex

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11 Comments

talex Over a year ago

But better refactor this to have thous methods in different classes.

John B Over a year ago

Generally considered bad practice to mock the class under test.

talex Over a year ago

@JohnB Yes. It is wy I'm added comment to separate class.

John B Over a year ago

Didn't realize that was a comment on your own post. Might have been better to edit your post to put the expansion in the body.

talex Over a year ago

@JohnB It was not part of answer, just general hint. But I edited my answer.

|

Community · Accepted Answer · 2017-05-23 10:32:29Z

2

Now that you have posted it, the answer to how to mock it is here.

testing-java-sockets

edited May 23, 2017 at 10:32

CommunityBot

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answered Nov 25, 2014 at 13:49

John B

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1 Comment

Lakshya Over a year ago

but I am not using socket in my first method?

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