How to use should_get_results_for_methods method of org.mockito.internal.stubbing.InvocationContainerImplStubbingTest class

Yes, you are doing it right.

You are injecting a mock repository into a real service, then testing the service. When it comes to business logic in your service, anything could be happening. That's why it's important to verify the code with known inputs and known outputs, just like you're doing.

1. You're checking the result of the business logic, given the response from the repository. This particular code is fairly straightforward, but imagine if the business logic was providing an average or a sum, not just the same value provided from the repository.

2. and 3. The verify and the assertEquals are testing different things. The verify checks that your repository method was called, the assert checks that the service responded with the correct value. Imagine that your service method had a hard-coded return 2L. The assertEquals would pass, but the verify would fail.

3. Yes, you're doing it right. What you're testing is linked to Why you're testing. Whether a particular assertion or verify is required is usually down to the individual situation. In this case, there is little point in testing that your repository method returns 2L, but there is a good case for testing that your service returns 2L. Similarly, there is no point in testing that the service method has been called, but there's a good case for testing that the repository method has been called.

You now have the tools to test your service, the next step is determining which tests to write.

If you are able to set a fixed number of calls to expect, it can be done with an ArgumentCaptor:

import static org.hamcrest.CoreMatchers.hasItem;

@Captor ArgumentCaptor<String> arg;

@Before
public void setUp() throws Exception {
    // init the @Captor
    initMocks(this);
}

@Test
public void testWithTimeoutCallOrderDoesntMatter() throws Exception {
    // there must be exactly 99 calls
    verify(myMock, timeout(5000).times(99)).myMethod(arg.capture());
    assertThat(arg.getAllValues(), hasItem("expectedArg"));
}

Another way is to specify all the expected values to verify, but those need to be provided in the exact order that they are invoked. The difference to the above solution is that this doesn't fail even if the mock is additionally called with some non-verified arguments. In other words, no need to know the number of total invocations. Code example:

@Test
public void testWithTimeoutFollowingCallsDoNotMatter() throws Exception {
    // the order until expected arg is specific
    verify(callback, timeout(5000)).call("firstExpectedArg");
    verify(callback, timeout(5000)).call("expectedArg");
    // no need to tell more, if additional calls come after the expected arg
    // verify(callback, timeout(5000)).call("randomArg");
}

You can use a Mockito Spy for this. If you setup anotherObj as a spy you can verify method calls on that object. In your example you need to make sure that the call to foo uses the spy instead of an ordinary implementation of anotherObj. The spy is setup something like this:

AnotherClass anotherObjSpy = Mockito.spy(new AnotherClass());
// do stuff -- e.g. anotherObjSpy.foo(...);
verify(anotherObjSpy).codePath1(...);

Add below code or maven equivalent:

testRuntimeOnly "org.junit.platform:junit-platform-commons:1.7.0"

Explnation:
ClassNamePatternFilterUtils belongs to platfrom-commons which is transitive dependency. This class introduced in the 1.7.0 version. Hence, needs to explicity add the dependency.

There is a type-safe way: use ArgumentMatchers.any() and qualify it with the type:

ArgumentMatchers.<AsyncCallback<ResponseX>>any()

Technically speaking both "mocks" and "spies" are a special kind of "test doubles".

Mockito is unfortunately making the distinction weird.

A mock in mockito is a normal mock in other mocking frameworks (allows you to stub invocations; that is, return specific values out of method calls).

A spy in mockito is a partial mock in other mocking frameworks (part of the object will be mocked and part will use real method invocations).

Mockito doesn't generate any byte code at compile time and hence is not affected by the used compiler. Same holds true for dexmaker. (they don't have any hooks into Gradle during build)

So you can simply continue to use Mockito, even with Jack compiler. Note that I have a test project which confirms this.

Why it didn't work

You're mocking Result.iterator():

when(deviceDataResultMock.iterator()).thenReturn(resultIterator);

But you didn't mock Result.spliterator(), or at least I didn't see it, which is what's being called by Result.stream(), which is just Collection.stream():

default Stream<E> stream() {
    return StreamSupport.stream(spliterator(), false);
}

So, you'll have to mock the spliterator() method as well, and probably a few others, too! Alternatively, tell Mockito to call default methods:

Can you make mockito (1.10.17) work with default methods in interfaces?

A comment on mocking in general

I'm not convinced that mocking the jOOQ API is a very good idea. The jOOQ API is vast, and you'll likely forget to mock this or that method as this question here has aptly shown. With your current setup, you're planning on updating your mock every time you project a new column? E.g. you're doing this:

when(recordMock.get(DEVICEID.getName()).thenReturn(deviceId);

What if the column is renamed? Or another column is projected? You'll have to update this test. That feels like quite the chore, and it's very error prone.

While jOOQ itself has JDBC mocking capabilities, please consider the bold disclaimer on that manual page:

Disclaimer: The general idea of mocking a JDBC connection with this jOOQ API is to provide quick workarounds, injection points, etc. using a very simple JDBC abstraction. It is NOT RECOMMENDED to emulate an entire database (including complex state transitions, transactions, locking, etc.) using this mock API. Once you have this requirement, please consider using an actual database product instead for integration testing, rather than implementing your test database inside of a MockDataProvider

When working with databases, it's usually best to resort to running integration tests, see the following resources for some details:

• Integration testing with Jooq
• Using H2 as a Test Database Product with jOOQ
• How to Integration Test Stored Procedures with jOOQ
• Using Testcontainers to Generate jOOQ Code

Of course, you can write a few smoke tests to ensure jOOQ works correctly if you don't trust jOOQ (jOOQ being an external dependency). But the jOOQ unit and integration tests are vast, so in general, you should be able to trust core types like Result or Record to do the right thing for you. What you really want to test is your query correctness, and that, you can only integration test against an actual database instance.

For the mocks initialization, using the runner or the MockitoAnnotations.initMocks are strictly equivalent solutions. From the javadoc of the MockitoJUnitRunner :

JUnit 4.5 runner initializes mocks annotated with Mock, so that explicit usage of MockitoAnnotations.initMocks(Object) is not necessary. Mocks are initialized before each test method.

The first solution (with the MockitoAnnotations.initMocks) could be used when you have already configured a specific runner (SpringJUnit4ClassRunner for example) on your test case.

The second solution (with the MockitoJUnitRunner) is the more classic and my favorite. The code is simpler. Using a runner provides the great advantage of automatic validation of framework usage (described by @David Wallace in this answer).

Both solutions allows to share the mocks (and spies) between the test methods. Coupled with the @InjectMocks, they allow to write unit tests very quickly. The boilerplate mocking code is reduced, the tests are easier to read. For example:

@RunWith(MockitoJUnitRunner.class)
public class ArticleManagerTest {

    @Mock private ArticleCalculator calculator;
    @Mock(name = "database") private ArticleDatabase dbMock;
    @Spy private UserProvider userProvider = new ConsumerUserProvider();

    @InjectMocks private ArticleManager manager;

    @Test public void shouldDoSomething() {
        manager.initiateArticle();
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        manager.finishArticle();
        verify(database).removeListener(any(ArticleListener.class));
    }
}

Pros: The code is minimal

Cons: Black magic. IMO it is mainly due to the @InjectMocks annotation. With this annotation "you loose the pain of code" (see the great comments of @Brice)

The third solution is to create your mock on each test method. It allow as explained by @mlk in its answer to have "self contained test".

public class ArticleManagerTest {

    @Test public void shouldDoSomething() {
        // given
        ArticleCalculator calculator = mock(ArticleCalculator.class);
        ArticleDatabase database = mock(ArticleDatabase.class);
        UserProvider userProvider = spy(new ConsumerUserProvider());
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.initiateArticle();

        // then 
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        // given
        ArticleCalculator calculator = mock(ArticleCalculator.class);
        ArticleDatabase database = mock(ArticleDatabase.class);
        UserProvider userProvider = spy(new ConsumerUserProvider());
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.finishArticle();

        // then
        verify(database).removeListener(any(ArticleListener.class));
    }
}

Pros: You clearly demonstrate how your api works (BDD...)

Cons: there is more boilerplate code. (The mocks creation)

My recommandation is a compromise. Use the @Mock annotation with the @RunWith(MockitoJUnitRunner.class), but do not use the @InjectMocks :

@RunWith(MockitoJUnitRunner.class)
public class ArticleManagerTest {

    @Mock private ArticleCalculator calculator;
    @Mock private ArticleDatabase database;
    @Spy private UserProvider userProvider = new ConsumerUserProvider();

    @Test public void shouldDoSomething() {
        // given
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.initiateArticle();

        // then 
        verify(database).addListener(any(ArticleListener.class));
    }

    @Test public void shouldDoSomethingElse() {
        // given
        ArticleManager manager = new ArticleManager(calculator, 
                                                    userProvider, 
                                                    database);

        // when 
        manager.finishArticle();

        // then 
        verify(database).removeListener(any(ArticleListener.class));
    }
}

Pros: You clearly demonstrate how your api works (How my ArticleManager is instantiated). No boilerplate code.

Cons: The test is not self contained, less pain of code