Core API

Core API

Core API is ment to be used for testing raw Java sockets. If you need too test HTTP connections, use the HTTP module.

Dependency

Add the following dependency to your build system

<dependency>
    <groupId>net.javacrumbs</groupId>
    <artifactId>mock-socket-core</artifactId>
    <version>0.9.0</version>
</dependency>

API

The API was inspired by Mockito framework. You have to start with static import:

import static net.javacrumbs.mocksocket.MockSocket.*; 

Mock response

Then you can write the test.

@Test
public void testResponse() throws Exception
{
	byte[] mockData = new byte[]{1,2,3,4};
	expectCall().andReturn(data(mockData));
	
	Socket socket = SocketFactory.getDefault().createSocket("example.org", 1234);
	byte[] data = IOUtils.toByteArray(socket.getInputStream());
	socket.close();
	assertThat(data, is(mockData));
}

This test is not much useful since it tests that Java sockets work, but I hope you have the idea.

Clean-up

It's necessary to call MockSocket.reset() after each test.

@After
public void tearDown()
{
	reset();
}

Validate request data

It's possible to compare the request data like this.

@Test
public void testRequest() throws Exception
{
	byte[] dataToWrite = new byte[]{5,4,3,2};
	expectCall().andReturn(emptyResponse());
	
	Socket socket = SocketFactory.getDefault().createSocket("example.org", 1234);
	IOUtils.write(dataToWrite, socket.getOutputStream());
	socket.close();
	assertThat(recordedConnections().get(0), data(is(dataToWrite)));
	assertThat(recordedConnections().get(0), address(is("example.org:1234")));
}

Condition based mock response

Sometimes it is not feasible to return mock responses based on the order of requests. In such situation, it's possible to use condition based mocks.

@Test
public void testConditionalAddress() throws Exception
{
	byte[] mockData = new byte[]{1,2,3,4};
	expectCall().andWhenRequest(address(is("example.org:1234"))).thenReturn(data(mockData));
	
	Socket socket = SocketFactory.getDefault().createSocket("example.org", 1234);
	byte[] data = IOUtils.toByteArray(socket.getInputStream());
	socket.close();
	assertThat(data, is(mockData));
}

or

@Test
public void testConditionalData() throws Exception
{
	byte[] dataToWrite = new byte[]{5,4,3,2};
	byte[] mockData = new byte[]{1,2,3,4};
	expectCall().andWhenRequest(data(is(dataToWrite))).thenReturn(data(mockData));
	
	Socket socket = SocketFactory.getDefault().createSocket("example.org", 1234);
	IOUtils.write(dataToWrite, socket.getOutputStream());
	byte[] data = IOUtils.toByteArray(socket.getInputStream());
	socket.close();
	assertThat(data, is(mockData));
}	

Matchers

As you have seen, Mock socket contains several built-in matchers.

Method	Description	Example
data(Matcher dataMatcher)	Compares data in andWhenRequest method	expectCall().andWhenRequest(data(is(dataToWrite))).thenReturn(data(mockData))
withData(InputStream data)	Compares data in andWhenRequest method	expectCall().andWhenRequest(withData(inputStream)).thenReturn(DATA1)
address(Matcher addressMatcher)	Compares address in andWhenRequest method	expectCall().andWhenRequest(address(is("example.org:1234"))).thenReturn(data(mockData));
data(Matcher dataMatcher)	Compares response data	assertThat(recordedConnections().get(0), data(is(dataToWrite)));