How to mock out InetAddress.getLocalHost() using JMockit

Question

The InetAddress constructor is not visible because the factory pattern is used.

final InetAddress anyInstance = InetAddress.getLocalHost();
    new NonStrictExpectations(InetAddress.class) {
      {
        anyInstance.getHostAddress();
        result = "192.168.0.101";
      }
    };

When I try to use the factory method to get an instance for partial mocking I get the error:

java.lang.IllegalStateException: Missing invocation to mocked type at this point; please make sure such invocations appear only after the declaration of a suitable mock field or parameter

Answer 1

You need to specify that InetAddress and any subclasses should be mocked:

@Test
public void mockAnyInetAddress(@Capturing final InetAddress anyInstance)
    throws Exception
{
    new Expectations() {{
        anyInstance.getHostAddress(); result = "192.168.0.101";
    }};

    String localHostAddress = InetAddress.getLocalHost().getHostAddress();

    assertEquals("192.168.0.101", localHostAddress);
}