Mockito: InvalidUseOfMatchersException

I have a command line tool that performs a DNS check. If the DNS check succeeds, the command proceeds with further tasks. I am trying to write unit tests for this using Mockito. Here's my code:

public class Command() {
    // ....
    void runCommand() {
        // ..
        dnsCheck(hostname, new InetAddressFactory());
        // ..
        // do other stuff after dnsCheck
    }

    void dnsCheck(String hostname, InetAddressFactory factory) {
        // calls to verify hostname
    }
}

I am using InetAddressFactory to mock a static implementation of the InetAddress class. Here's the code for the factory:

public class InetAddressFactory {
    public InetAddress getByName(String host) throws UnknownHostException {
        return InetAddress.getByName(host);
    }
}

Here's my unit test case:

@RunWith(MockitoJUnitRunner.class)
public class CmdTest {

    // many functional tests for dnsCheck

    // here's the piece of code that is failing
    // in this test I want to test the rest of the code (i.e. after dnsCheck)
    @Test
    void testPostDnsCheck() {
        final Cmd cmd = spy(new Cmd());

        // this line does not work, and it throws the exception below:
        // tried using (InetAddressFactory) anyObject()
        doNothing().when(cmd).dnsCheck(HOST, any(InetAddressFactory.class));
        cmd.runCommand();
    }
}

Exception on running testPostDnsCheck() test:

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: 
Invalid use of argument matchers!
2 matchers expected, 1 recorded.
This exception may occur if matchers are combined with raw values:
    //incorrect:
    someMethod(anyObject(), "raw String");
When using matchers, all arguments have to be provided by matchers.
For example:
    //correct:
    someMethod(anyObject(), eq("String by matcher"));

Any input on how to solve this?


The error message outlines the solution. The line

doNothing().when(cmd).dnsCheck(HOST, any(InetAddressFactory.class))

uses one raw value and one matcher, when it's required to use either all raw values or all matchers. A correct version might read

doNothing().when(cmd).dnsCheck(eq(HOST), any(InetAddressFactory.class))

I had the same problem for a long time now, I often needed to mix Matchers and values and I never managed to do that with Mockito.... until recently ! I put the solution here hoping it will help someone even if this post is quite old.

It is clearly not possible to use Matchers AND values together in Mockito, but what if there was a Matcher accepting to compare a variable ? That would solve the problem... and in fact there is : eq

when(recommendedAccessor.searchRecommendedHolidaysProduct(eq(metas), any(List.class), any(HotelsBoardBasisType.class), any(Config.class)))
            .thenReturn(recommendedResults);

In this example 'metas' is an existing list of values