How to use shouldVerifyExactNumberOfInvocationsUsingMatcher method of org.mockitousage.verification.BasicVerificationInOrderTest class

If you want to do a pure unit test then for the line

service.getJdbcTemplate().query("....");

You will need to mock the Service, then the service.getJdbcTemplate() method to return a mock JdbcTemplate object, then mock the query method of mocked JdbcTemplate to return the List you need. Something like this:

@Mock
Service service;

@Mock
JdbcTemplate jdbcTemplate;


@Test
public void testGetUserNames() {

    List<String> userNames = new ArrayList<String>();
    userNames.add("bob");

    when(service.getJdbcTemplate()).thenReturn(jdbcTemplate);
    when(jdbcTemplate.query(anyString(), anyObject()).thenReturn(userNames);

    String retVal = Class.getUserNames("test");
    assertEquals("bob", retVal);
}

The above doesn't require any sort of Spring support. If you were doing an Integration Test where you actually wanted to test that data was being pulled from a DB properly, then you would probably want to use the Spring Test Runner.

With Mockito framework, you can use AdditionalMatchers

ClassA classA = Mockito.mock(ClassA.class);
Mockito.when(classA.getString(Matchers.eq("a"))).thenReturn("something"); 
Mockito.when(classA.getString(AdditionalMatchers.not(Matchers.eq("a")))).thenReturn("something else");

Hope it helps.

From the PowerMock Private Method Example:

@RunWith(PowerMockRunner.class)
// We prepare PartialMockClass for test because it's final or we need to mock private or static methods
@PrepareForTest(PartialMockClass.class)
public class YourTestCase {
@Test
public void privatePartialMockingWithPowerMock() {        
    PartialMockClass classUnderTest = PowerMockito.spy(new PartialMockClass());

    // use PowerMockito to set up your expectation
    PowerMockito.doReturn(value).when(classUnderTest, "methodToMock", "parameter1");

    // execute your test
    classUnderTest.execute();

    // Use PowerMockito.verify() to verify result
    PowerMockito.verifyPrivate(classUnderTest, times(2)).invoke("methodToMock", "parameter1");
}

So to apply this to your code, I think it might become:

@RunWith(PowerMockRunner.class)
@PrepareForTest(CodeWithPrivateMethod.class)
public class PowerMock_Test {
    @Test(expected = RuntimeException.class)
    public void when_gambling_is_true_then_always_explode() throws Exception {
        CodeWithPrivateMethod spy = PowerMockito.spy(new CodeWithPrivateMethod());

        PowerMockito.doReturn(true).when(spy, "doTheGamble", anyString(), anyInt());


/* 1 */ PowerMockito.verifyPrivate(spy, times(0)).invoke("doTheGamble", anyString(), anyInt());            
        spy.meaningfulPublicApi();
/* 2 */ PowerMockito.verifyPrivate(spy, times(2)).invoke("doTheGamble", anyString(), anyInt());            
    }
}

I just coded that in the editor here. No tests have actually been run, and no bugs have been harmed in the crafting of this code.

To test an application in isolation when the real production JMS provider is not available you can use one of:

1. JMS mock:
   When testing your applications you can simulate the non-existing dependencies using test doubles. You can use a JMS mock which will simulate the behaviour of a real JMS provider. API simulation tools will allow you to create JMS mocks (just choose a tool that supports JMS, for example Traffic Parrot). Using a JMS mock will allow you for a high level of flexibility during testing. You will be able to test typical production-like test scenarios but also hypothetical situations by setting up your mock to return almost any type of message. You will also be able to simulate different types of errors, which is often hard to do with real JMS providers. Have a look at this introduction video to JMS service virtualization for ActiveMq (service virtualization is a different name for a mock) or this one for IBM MQ. Note, these videos are from Traffic Parrot, but the principle described there will apply to any tool you choose.

2. JMS provider test instance:
   You can run a JMS provider on your laptop or in one of your test environments and connect your application to it instead of the production provider. When you use open source providers in production like ActiveMQ or RabbitMQ, it should be easy to run one of them on your laptop as well because they are lightweight and free. For IBM Websphere MQ, you can use the free IBM MQ for Developers.

3. JMS class mock:
   You can use Mockito in unit tests to mock interactions with JMS classes. This solution comes with all the trade-offs of unit testing. For more information on those see testing pyramid.

If you would like to black box test your application, use one of the solutions I have described above.

import org.springframework.test.util.ReflectionTestUtils;

@RunWith(MockitoJUnitRunner.class)
public CustomServiceTest{

@InjectMocks
private CustomServiceImpl customService;

@Mock
private DataService dataService;

@Before
public void setup() {
    ReflectionTestUtils.setField(customService, "url", "http://someurl");
}    
...
}

In new Mockito versions you can use stubbing consecutive calls to throw exception on first can and returning a value on a second call.

when(mock.someMethod("some arg"))
    .thenThrow(new RuntimeException())
    .thenReturn("foo");

https://javadoc.io/doc/org.mockito/mockito-core/latest/org/mockito/Mockito.html#10

With PowerMock you can mock constructors. See example

I'm not with an IDE right now, but would be something like this:

  UserQueries userQueries = PowerMockito.mock(UserQueries.class);
  PowerMockito.whenNew(UserQueries.class).withArguments(Mockito.any(CrudService.class)).thenReturn(userQueries);

You need to run your test with PowerMockRunner (add these annotations to your test class):

@RunWith(PowerMockRunner.class)
@PrepareForTest(UserQueries .class)

If you cannot use PowerMock, you have to inject a factory, as it says @Briggo answer.

Hope it helps

You need to have prepared the class calling the constructor, not the class on which the constructor is called, the following should fix you up:

@PrepareForTest(DummyTarget.class)

For more information check this page.

PowerMock 1.6 isn't compatible with Mockito 2.7 (take a look at https://github.com/powermock/powermock/wiki/Mockito#supported-versions)

You should use PowerMock 1.7.0RC2 (or 1.7.0RC3 if 1.7.0RC2 doesn't work), and also use powermock-api-mockito2 instead of powermock-api-mockito.