如何在Socket和OutputStreamWriter上执行JUnit测试

问题描述

想寻求有关我的单元测试如何关闭套接字的方法的帮助，并且outputstreamwriter将能够通过。现在，我的单元测试只能涵盖引发Exception的部分。

这是方法：

private final void CloseConnection() {
    ErrorHandler objErrHdl = new ErrorHandler();

    try {
        out.close();
        clientSocket.close();
    } catch ( IOException e ) {
        objErrHdl.LogError( this.getClass().getName(),"CloseConnection","Failed TO CLOSE CONNECTION",e.toString() );
    } catch ( Exception e ) {
        objErrHdl.LogError( this.getClass().getName(),e.toString() );
    }
}

这是我的单元测试：

        @Test
    public void testCloseConnection() throws IOException,NoSuchMethodException,SecurityException,illegalaccessexception,IllegalArgumentException,InvocationTargetException {

    serverSocket = new ServerSocket(6668);
    Method method = Systematic.class.getDeclaredMethod("CloseConnection");
        method.setAccessible(true);
        method.invoke(systematic);
        clientSocket = new Socket("127.0.0.1",6668);
        clientSocket.close(); 
        out.close(); 
    }

    @Test
    public void testCloseConnectionException() throws NoSuchMethodException,InvocationTargetException,IOException {
        Method method = Systematic.class.getDeclaredMethod("CloseConnection");
        method.setAccessible(true);
        method.invoke(systematic);

        clientSocket = new Socket("0",33654);
    }

    @Test
    public void testCloseConnectionIOException() throws NoSuchMethodException,IOException {

        Method method = Systematic.class.getDeclaredMethod("CloseConnection");
        method.setAccessible(true);
        Socket s =  (Socket) method.invoke(systematic);
        Mockito.when(s).thenThrow(new IOException());
    }

正如我所说，单元测试的testCloseConnectionException是覆盖我正在测试的CloseConnection方法的唯一成功方法。谢谢。

解决方法

我想您在业务代码和测试中使用的对象clientSocket和out不相同。

在测试中，您创建了新对象，但是这些对象不会传播到被测类中。

这是我对您的测试的主张：

正在测试的类，类似于您的

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.net.Socket;

public class SomeClass {

    private OutputStreamWriter out = null;
    private Socket clientSocket = null;

    private final void CloseConnection() {

        try {
            out.close();
            clientSocket.close();
        } catch (IOException e) {
            System.out.println(e);
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}

并对其进行测试

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.lang.reflect.Method;
import java.net.Socket;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class SomeClassTest {

    @Mock
    private OutputStreamWriter out;

    @Mock
    private Socket clientSocket;

    @InjectMocks
    private SomeClass someClass;

    @Test
    public void testCloseConnection() throws Exception {

        // run test method
        Method method = SomeClass.class.getDeclaredMethod("CloseConnection");
        method.setAccessible(true);
        method.invoke(someClass);

        // verify if action was taken
        Mockito.verify(clientSocket).close();
        Mockito.verify(out).close();

        // and nothing else was not occurred
        Mockito.verifyNoMoreInteractions(clientSocket,out);
    }

    @Test
    public void testCloseConnectionIOException1() throws Exception {

        // throw Exception on out.close()
        Mockito.doThrow(new IOException()).when(out).close();

        // run test method
        Method method = SomeClass.class.getDeclaredMethod("CloseConnection");
        method.setAccessible(true);
        method.invoke(someClass);

        // out.close() was called
        Mockito.verify(out).close();
        // and nothing else on out
        Mockito.verifyNoMoreInteractions(out);

        // no call on clientSocket - because out.close() throw Exception
        Mockito.verifyNoInteractions(clientSocket);
    }
}

在测试中，我们可以模拟java io类，没有必要再次测试那些类。我们要在现实世界中的某些情况下测试我们的应用程序和行为。