How to use clearMocks method of org.mockito.MockitoFramework class

You are confusing a Mock with a Spy.

In a mock all methods are stubbed and return "smart return types". This means that calling any method on a mocked class will do nothing unless you specify behaviour.

In a spy the original functionality of the class is still there but you can validate method invocations in a spy and also override method behaviour.

What you want is

MyProcessingAgent mockMyAgent = Mockito.spy(MyProcessingAgent.class);

A quick example:

static class TestClass {

    public String getThing() {
        return "Thing";
    }

    public String getOtherThing() {
        return getThing();
    }
}

public static void main(String[] args) {
    final TestClass testClass = Mockito.spy(new TestClass());
    Mockito.when(testClass.getThing()).thenReturn("Some Other thing");
    System.out.println(testClass.getOtherThing());
}

Output is:

Some Other thing

NB: You should really try to mock the dependencies for the class being tested not the class itself.

The parentheses are poorly placed.

You need to use:

doThrow(new Exception()).when(mockedObject).methodReturningVoid(...);
                                          ^

and NOT use:

doThrow(new Exception()).when(mockedObject.methodReturningVoid(...));
                                                                   ^

This is explained in the documentation

I think you do need to cast it, but it shouldn't be too bad:

Foo<Bar> mockFoo = (Foo<Bar>) mock(Foo.class);
when(mockFoo.getValue()).thenReturn(new Bar());

If you want to test using the URL, then you will need to start a server from your test. You can explicitly start an embedded server, which is pretty common for tests. Something like

public class MyResourceTest {

    public static final String BASE_URI = "http://localhost:8080/api/";
    private HttpServer server;

    @Before
    public void setUp() throws Exception {
        final ResourceConfig rc = new ResourceConfig(Service.class);
        server = GrizzlyHttpServerFactory.createHttpServer(URI.create(BASE_URI), rc);       
    }

    @After
    public void tearDown() throws Exception {
        server.stop();
    }

    @Test
    public void testService() {
        Client client = ClientBuilder.newClient();
        WebTarget target = client.target(BASE_URI).path("service");
        ...
    }
}

It's basically an integration test. You're starting the Grizzly container and loading a ResourceConfig to the server with only the Service class. Of course you could add more classes to the configuration. You can use "real" resource config if you wanted.

The above test uses this dependency

<dependency>
    <groupId>org.glassfish.jersey.containers</groupId>
    <artifactId>jersey-container-grizzly2-http</artifactId>
    <version>${jersey2.version}</version>
</dependency>

Another option, which is the one I prefer, is to make use of the Jersey Test Framework, which will start an embedded container for you. A test might look something more like

public class SimpleTest extends JerseyTest {
 
    @Override
    protected Application configure() {
        return new ResourceConfig(Service.class);
    }
 
    @Test
    public void test() {
        String hello = target("service").request().get(String.class);
    }
}

Using this dependency

<dependency>
    <groupId>org.glassfish.jersey.test-framework.providers</groupId>
    <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
    <version>${jersey2.version}</version>
    <scope>test</scope>
</dependency>

And embedded Grizzly container will get started under the hood, with your ResourceConfig configuration. In both examples above it is assumed the @Path value for the Service class is service, as you can see in the test URLs.

Some Resources

• Jersey 2 Test Framework user guide

Some Examples

• How to write Unit Test for this class using Jersey 2 test framework
• How to in-memory unit test Spring-Jersey
• Example with Mockito, Test Framework, and Jersey 2
• Example with Mockito, Test Framework, and Jersey 1

UPDATE

If you're not using Maven, here are the jars you will need to run an embedded Grizzly container for the Jersey Test Fraemwork

I usually search for all my jars here. You can select the version and there should be a link in the next page, to download. You can use the search bar to search for the others.

Here's a simple running example, once you have all the jars

import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.core.DefaultResourceConfig;
import com.sun.jersey.spi.container.servlet.WebComponent;
import com.sun.jersey.test.framework.JerseyTest;
import com.sun.jersey.test.framework.WebAppDescriptor;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import junit.framework.Assert;
import org.junit.Test;

public class SimpleTest extends JerseyTest {
    
    @Path("service")
    public static class Service {
        @GET
        public String getTest() { return "Hello World!"; }
    }

    public static class AppConfig extends DefaultResourceConfig {
        public AppConfig() {
            super(Service.class);
        }
    }
    
    @Override
    public WebAppDescriptor configure() {
        return new WebAppDescriptor.Builder()
                .initParam(WebComponent.RESOURCE_CONFIG_CLASS, 
                           AppConfig.class.getName())
                .build();
    }
    
    @Test
    public void doTest() {
        WebResource resource = resource().path("service");
        String result = resource.get(String.class);
        Assert.assertEquals("Hello World!", result);
        System.out.println(result);
    }
}

You're most likely not going to have the resources and ResourceConfig in the same class as the test, but I just want to keep it simple and all visible in one class.

Whether you are using a web.xml or a ResourceConfig subclass (as shown above), you can cut down what you test by using a separate ResourceConfig, built in the test class, as I have done. Otherwise, if you are using your normal ResourceConfig class, you can just replace it in the configure method.

The configure method, is pretty much just building a web.xml file, just in Java code. You can see different methods in the WebAppDescriptor.Builder, like initParam, which is the same as an <init-param> in your web xml. You can simply use the string in the arguments, but there are some constants, as I used above.

The @Test is you usual JUnit test that will run. It is using the Jersey Client. But instead of creating the Client, you can simply just use the preconfigured Client by just accessing the resource() method, which returns a WebResource. If you are familiar with the Jersey Client, then this class should not be new to you.

Something like this should do it (not tested):

doAnswer(new Answer() {
    public Object answer(InvocationOnMock invocation) {
        Object[] args = invocation.getArguments();
        List<?> list = (List<?>) args[0];
        list.clear();
        return null;
    }
}).when(test).clearList(any(List.class));

The right thing to do is to restructure your code to make it more testable as shown below. Restructuring your code to remove the direct dependency on Date will allow you to inject different implementations for normal runtime and test runtime:

interface DateTime {
    Date getDate();
}

class DateTimeImpl implements DateTime {
    @Override
    public Date getDate() {
       return new Date();
    }
}

class MyClass {

    private final DateTime dateTime;
    // inject your Mock DateTime when testing other wise inject DateTimeImpl

    public MyClass(final DateTime dateTime) {
        this.dateTime = dateTime;
    }

    public long getDoubleTime(){
        return dateTime.getDate().getTime()*2;
    }
}

public class MyClassTest {
    private MyClass myClassTest;

    @Before
    public void setUp() {
        final Date date = Mockito.mock(Date.class);
        Mockito.when(date.getTime()).thenReturn(30L);

        final DateTime dt = Mockito.mock(DateTime.class);
        Mockito.when(dt.getDate()).thenReturn(date);

        myClassTest = new MyClass(dt);
    }

    @Test
    public void someTest() {
        final long doubleTime = myClassTest.getDoubleTime();
        assertEquals(60, doubleTime);
    }
}

I don't quite follow what problem you're having using Mockito. Assuming you create a mock of the interface that contains your myMethod() method, you can then verify only the parameters to the method that you are interested in. For example (assuming the interface is called MyInterface and using JUnit 4):

@Test
public void test() {
    MyInterface myInterface = mock(MyInterface.class);
    FooBar expectedFooBar = new FooBar();        

    // other testing stuff

    verify(myInterface).myMethod(any(), any(), eq(expectedFooBar), any(), ...);
}

You'll need to do a static import on the Mockito methods for this to work. The any() matcher doesn't care what value has been passed when verifying.

You can't avoid passing something for every argument in your method (even if it's only NULL).

Note that documentToPojo takes a Class as its second argument. any(Foo.class) returns an argument of type Foo, not of type Class<Foo>, whereas eq(WorkItemDTO.class) should return a Class<WorkItemDTO> as expected. I'd do it this way:

when(mongoUtil.documentToPojo(
    Mockito.any(Document.class),
    Mockito.eq(WorkItemDTO.class))).thenReturn(...);

The article isn't very clear as it misses out the setup steps. By visiting the GitHub project linked in the article, you can see the full source code which explains those missing steps:

1) The code samples are extracted from a test class testing a specific activity. As part of the setup (i.e. in @Before), it replaces the Activity's reference to a GitHub API implementation with a mock one. It then calls the Activity's onCreate().

2) During onCreate(), the activity makes a call to the now-replaced GitHub API, passing in its Callback object.

Those first two steps explain why the Mockito.verify(mockApi).repositories(Mockito.anyString(), cb.capture()); step at the beginning of each test works. As the test is run after @Before, the mockApi has indeed had a call on its repositories() method.

The rest of the code is easier to understand once that's in place. As he's only created a mockApi, but not changed the actual Callback being used, the activity's content is changed. The rest of the code then verifies that those changes have taken place, either by checking a ListView or the Toasts.

So to answer your question, you need to:

1) At the start of your test method, replace the AuthAPI's loginService object with your mockApi object, then call AuthAPI.Login().

2) Use verify() as you already are to check that the function has been called.

3) Create a sample AuthObject and pass it to the cb.getValue().success() function.

4) Obtain the AuthObject from your Bus and assert that it is the same one you sent to the callback.success() function.

This tests that your AuthAPI.Login() correctly sends to your Bus the AuthObject that it would retrieve from Retrofit.

(I realise the SO question was written some time ago, but as I came across the same article and had the same confusion very recently, I thought this answer could be useful for others.)