How to use RealMethod class of org.mockito.internal.invocation package

Even more meaningful :

import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;

// ...

verify(dependency, never()).someMethod();

The documentation of this feature is there §4 "Verifying exact number of invocations / at least x / never", and the never javadoc is here.

Thanks to @J Andy's line of thought, I realised that I had been heading down the wrong path on this. In Update 1 I was trying to inject the mock service into the MockMvc but after taking a step back I realised that it's not the MockMvc that was under test, it was the PolicyController I wanted to test.

To give a bit of background, I wanted to avoid a traditional unit test of the @Controllers in my Spring MVC application because I wanted to test things that are only provided by running the controllers within Spring itself (e.g. RESTful calls to controller actions). This can be achieved by using the Spring MVC Test framework which allows you to run your tests within Spring.

You'll see from the code in my initial question that I was running the Spring MVC tests in a WebApplicationContext (i.e. this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build(); ) whereas what I should have been doing was running standalone. Running standalone allows me to directly inject the controller I want to test and, therefore, have control over how the service is injected into the controller (i.e. force a mock service to be used).

This is easier explained in code. So for the following controller:

import javax.validation.Valid;

import name.hines.steven.medical_claims_tracker.domain.Benefit;
import name.hines.steven.medical_claims_tracker.domain.Policy;
import name.hines.steven.medical_claims_tracker.services.DomainEntityService;
import name.hines.steven.medical_claims_tracker.services.PolicyService;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

@Controller
@RequestMapping("/policies")
public class PolicyController extends DomainEntityController<Policy> {

    @Autowired
    private PolicyService service;

    @RequestMapping(value = "persist", method = RequestMethod.POST)
    public String createOrUpdate(@Valid @ModelAttribute("policy") Policy policy, BindingResult result) {
        if (result.hasErrors()) {
            return "createOrUpdatePolicyForm";
        }
        service.save(policy);
        return "redirect:list";
    }
}

I now have the following test class in which the service is successfully mocked out and my test database is no longer hit:

package name.hines.steven.medical_claims_tracker.controllers;

import static org.mockito.Matchers.isA;
import static org.mockito.Mockito.when;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.model;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.redirectedUrl;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.view;
import name.hines.steven.medical_claims_tracker.domain.Policy;
import name.hines.steven.medical_claims_tracker.services.PolicyService;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({ "classpath:/applicationContext.xml" })
public class PolicyControllerTest {

    @Mock
    PolicyService policyService;

    @InjectMocks
    PolicyController controllerUnderTest;

    private MockMvc mockMvc;

    @Before
    public void setup() {

        // this must be called for the @Mock annotations above to be processed
        // and for the mock service to be injected into the controller under
        // test.
        MockitoAnnotations.initMocks(this);

        this.mockMvc = MockMvcBuilders.standaloneSetup(controllerUnderTest).build();

    }

    @Test
    public void createOrUpdateFailsWhenInvalidDataPostedAndSendsUserBackToForm() throws Exception {
        // POST no data to the form (i.e. an invalid POST)
        mockMvc.perform(post("/policies/persist")).andExpect(status().isOk())
        .andExpect(model().attributeHasErrors("policy"))
        .andExpect(view().name("createOrUpdatePolicy"));
    }

    @Test
    public void createOrUpdateSuccessful() throws Exception {

        when(policyService.save(isA(Policy.class))).thenReturn(new Policy());

        mockMvc.perform(
                post("/policies/persist").param("companyName", "Company Name")
                .param("name", "Name").param("effectiveDate", "2001-01-01"))
                .andExpect(status().isMovedTemporarily()).andExpect(model().hasNoErrors())
                .andExpect(redirectedUrl("list"));
    }
}

I'm still very much learning when it comes to Spring so any comments that will improve my explanation would be welcomed. This blog post was helpful to me in coming up with this solution.

You do not need mockito to test this method, only a java.io.StringWriter.

Here is how you can write the test for a nominal use:

@Test
void status_written_in_csv_format() {
    // Setup
    WriteCsvToResponse objectUnderTest = new WriteCsvToResponse ();
    StringWriter stringWriter = new StringWriter();
    PrintWriter printWriter = new PrintWriter(stringWriter);

    // Given
    Status status = ...

    // When
    objectUnderTest.writeStatus(printWriter, status);

    // Then
    String actualCsv = stringWriter.toString();
    assertThat(actualCsv.split("\n"))
       .as("Produced CSV")
       .containsExactly(
         "id,storeId,status",
         "42,142,OK");
}

This example assume some things about your Status object, but you have the general idea. For assertions, I use AssertJ, but you can do the same with JUnit5 built-in assertions.

Hope this helps !

You should use RuntimeException or subclass it. Your method has to declare checked exception (example: findByState(String state) throws IOException;) otherwise use RuntimeException:

 when(userRepository.findByState("Karnataka"))
       .thenThrow(new RuntimeException("Exception"));

This is possible using Mockito.when:

Mockito.when(statusRepository.delete(any(Post.class)).thenReturn(Mono.empty());

...call the method and verify...

Mockito.verify(statusRepository).delete(any(Post.class));

I had the following problem: I had a method that was returning a Page<...> ,but I can use doNothing() only on void method ,so the fix is easy:

    @Override
    public Page<ThreadServiceModel> findAll(Pageable pageable) {
        return this.findAll(ThreadServiceModel.class, pageable);
    }

And here we go:

        //Will fail and the actualy findAll will be invoked:
        when(this.threadServices.findAll(ThreadServiceModel.class,pageable)).thenReturn(null);

        //Will fail ,cuz you cannot call doNothing() on something that returns values

        doNothing().when(this.threadServices).findAll(ThreadServiceModel.class,pageable);

        //This is the solution ,and when you use doReturn() the actual method will be NOT invoked,
        //+In my case i dont need value , but if i want I cant use...
        doReturn(null).when(this.threadServices).findAll(ThreadServiceModel.class,pageable);

So the solution is simple ,use the last method on the code that I have showed you :)

You can do that by instantiating your main class with parametrized constructor in your junit and then creating a spy from it.

Let's suppose your main class is A. Where B and C are its dependencies

public class A {

    private B b;

    private C c;

    public A(B b,C c)
    {
        this.b=b;
        this.c=c;
    }

    void method() {
        System.out.println("A's method called");
        b.method();
        c.method();
        System.out.println(method2());

    }

    protected int method2() {
        return 10;
    }
}

Then you can write junit for this using your parametrized class as below

@RunWith(MockitoJUnitRunner.class)
public class ATest {

    A a;

    @Mock
    B b;

    @Mock
    C c;

    @Test
    public void test() {
        a=new A(b, c);
        A spyA=Mockito.spy(a);

        doReturn(20).when(spyA).method2();

        spyA.method();
    }
}

Output of test class

A's method called
20

1. Here B and C are mocked object that you injected in your class A using parametrized constructor.
2. Then we created a spy of A called spyA.
3. We checked if spy is really working by modifying the return value of a protected method method2 in class A which could not have been possible if spyA was not an actual spy of A.

This occurs because you are using any() along with a real parameter VehicleCollection.class of type Class<VehicleCollection>.

Change it just like below, and you should be fine:

 when(queryBus.handle(any(VehicleCollection.class), any(GetVehicle.class))).thenAnswer(null);

Mockito explains why:

If you are using argument matchers, all arguments have to be provided by matchers.

E.g: (example shows verification but the same applies to stubbing):

    // Correct - eq() is also an argument matcher
    verify(mock).someMethod(anyInt(), anyString(), eq("third argument"));


    // Incorrect - exception will be thrown because third argument is given without argument matcher.
    verify(mock).someMethod(anyInt(), anyString(), "third argument");    

I've just finished comparing three BDD frameworks for Java. Obviously my findings have a fairly short use-by date.

Concordion

• Very flexible
• Very pretty report output
• Nice plugin framework
• Poorly documented. I had to read the source to figure it out (luckily its extremely good quality).
• Fixtures seemed likely to end up tightly coupled to the html.

EasyB

• Very shallow learning curve (even for non-Groovy Developers)
• Extremely powerful DBUnit integration
• Apparently no support for parameters (leads to either very vague stories or duplication between text and code (edit: actually there is but the documentation for it was very well hidden.)
• Story and Code are very tightly coupled (same file)
• Very basic report output
• Couldn't get IntelliJ plugin to work
• Inactive community (Maven plugin seems to have been broken for three months - not many code examples to draw on)

JBehave

• Extremely powerful and flexible (eg reduction of boiler-plate through composition of stories as pre-requisites)
• Extensive (if fragmented) documentation and examples
• Extensive (if overwhelming) support for different frameworks and environments
• Excellent separation of story files from code
• Looks to have a pretty active community and much more examples and discussion of it on web.
• Quite a steep learning curve (took me 3-4 times longer to figure out than Concordion/EasyB)

I didn't have the chance to try out Cuke4Duke of JDave as I would have liked, but will probably push for JBehave at this time.