How to use getInjected method of org.mockitousage.junitrule.InvalidTargetMockitoJUnitRuleTest class

To answer your second question first. If you're using JUnit 4, you can annotate your test with

@Test(expected=MyException.class)

to assert that an exception has occured. And to "mock" an exception with mockito, use

when(myMock.doSomething()).thenThrow(new MyException());

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).

You should use thenReturn or doReturn when you know the return value at the time you mock a method call. This defined value is returned when you invoke the mocked method.

thenReturn(T value) Sets a return value to be returned when the method is called.

@Test
public void test_return() throws Exception {
    Dummy dummy = mock(Dummy.class);
    int returnValue = 5;

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenReturn(returnValue);
    doReturn(returnValue).when(dummy).stringLength("dummy");
}

Answer is used when you need to do additional actions when a mocked method is invoked, e.g. when you need to compute the return value based on the parameters of this method call.

Use doAnswer() when you want to stub a void method with generic Answer.

Answer specifies an action that is executed and a return value that is returned when you interact with the mock.

@Test
public void test_answer() throws Exception {
    Dummy dummy = mock(Dummy.class);
    Answer<Integer> answer = new Answer<Integer>() {
        public Integer answer(InvocationOnMock invocation) throws Throwable {
            String string = invocation.getArgumentAt(0, String.class);
            return string.length() * 2;
        }
    };

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenAnswer(answer);
    doAnswer(answer).when(dummy).stringLength("dummy");
}

Here is a solution that will work for you particular case:

First of all you need to create a PersonMixin since you cannot add the required annotations to the mock.

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonProperty;


@JsonAutoDetect(getterVisibility = JsonAutoDetect.Visibility.NONE, isGetterVisibility = JsonAutoDetect.Visibility.NONE)
public interface PersonMixin {

    @JsonProperty
    String getName();

    @JsonProperty
    Integer getAge();
}

Now, use the object mapper like the in following code and you will get the same result as when you serialize the real object:

Person mockPerson = mock(Person.class);
when(mockPerson.getName()).thenReturn(name);
when(mockPerson.getAge()).thenReturn(age);
objectMapper.addMixInAnnotations(Person.class, PersonMixin.class);
try {
    System.out.println(objectMapper.writeValueAsString(mockPerson));
} catch (JsonProcessingException e) {
    e.printStackTrace();
    System.err.println("Failed to serialize mock object.");
}

Wiremock provides a simulator for HTTP-based APIs while Mockito provides the mock implementation of the method/object.

If we are using Mockito to mock HTTP-based method, it means we are trying to return the object/response without testing any code to invoke REST service, getting HTTP response and deserializing the same.

If we use the Wiremock, we will able to test close to reality as it will test invocation of REST call as well as deserialization of the response.

https://www.linkedin.com/pulse/what-difference-between-stub-mock-virtual-service-wojciech-bulaty/ is one good article to read, of course not by me :-)

MethodSorters is a new class introduced after Junit 4.6 release. This class declared three types of execution order, which can be used in your test cases while executing them.

1. NAME_ASCENDING(MethodSorters.NAME_ASCENDING) - Sorts the test methods by the method name, in lexicographic order.

2. JVM(null) - Leaves the test methods in the order returned by the JVM. Note that the order from the JVM my vary from run to run.

3. DEFAULT(MethodSorter.DEFAULT) - Sorts the test methods in a deterministic, but not predictable, order.

.

import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runners.MethodSorters;

//Running test cases in order of method names in ascending order

@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class OrderedTestCasesExecution {

    @Test
    public void secondTest() {
        System.out.println("Executing second test");
    }

    @Test
    public void firstTest() {
        System.out.println("Executing first test");
    }

    @Test
    public void thirdTest() {
        System.out.println("Executing third test");
    }
}

Output:

Executing first test
Executing second test
Executing third test

Reference: http://howtodoinjava.com/2012/11/24/ordered-testcases-execution-in-junit-4/

Since verifyNoMoreInteractions take an array of object we have to find a way to get all the created mocks.

You can create this class

public class MocksCollector {
    private final List<Object> createdMocks;

    public MocksCollector() {
        createdMocks = new LinkedList<Object>();
        final MockingProgress progress = new ThreadSafeMockingProgress();
        progress.setListener(new CollectCreatedMocks(createdMocks));
    }

    public Object[] getMocks() {
        return createdMocks.toArray();
    }
}

and then use it in your test :

    public class ATest {
    private final MocksCollector mocksCollector = new MocksCollector();

    @Test
    public void test() throws Exception {
        A a1 = mock(A.class);
        A a2 = mock(A.class);
        A a3 = mock(A.class);
        assertEquals("wrong amount of mocks", 3, mocksCollector.getMocks().length);
        verifyNoMoreInteractions(mocksCollector.getMocks());
        a3.doSomething();
        verifyNoMoreInteractions(mocksCollector.getMocks()); // fail
    }
}

or with annotations :

@RunWith(MockitoJUnitRunner.class)
public class A2Test {
    private final MocksCollector mocksCollector = new MocksCollector();

    @Mock
    private A a1;
    @Mock
    private A a2;
    @Mock
    private A a3;

    @Test
    public void test() throws Exception {
        assertEquals("wrong amount of mocks", 3, mocksCollector.getMocks().length);
        verifyNoMoreInteractions(mocksCollector.getMocks());
        a2.doSomething();
        verifyNoMoreInteractions(mocksCollector.getMocks()); // fail
    }
}

It works but it adds a dependency on mockito internal.

Use PowerMockito on top of Mockito.

Example code:

@RunWith(PowerMockRunner.class)
@PrepareForTest(DriverManager.class)
public class Mocker {

    @Test
    public void shouldVerifyParameters() throws Exception {

        //given
        PowerMockito.mockStatic(DriverManager.class);
        BDDMockito.given(DriverManager.getConnection(...)).willReturn(...);

        //when
        sut.execute(); // System Under Test (sut)

        //then
        PowerMockito.verifyStatic();
        DriverManager.getConnection(...);

    }

More information:

• Why doesn't Mockito mock static methods?

You don't need to use PowerMockito, and as its an Interface, theres no need to spy() as you are not relying on any non mocked logic.

It can be done like this, in your test class define a class variable.

private FlowCopyParamsBusinessManager flowCopyParamsBusinessManagerMock;

In an @Before annotated method:

flowCopyParamsBusinessManagerMock = Mockito.mock(FlowCopyParamsBusinessManager.class);
List<FlowCopyParams> flowCopyParamsList = new ArrayList<>();
when(flowCopyParamsBusinessManagerMock 
.findByAppli(Mockito.anyString(), Mockito.anyString()).thenReturn(flowCopyParamsList);

Then refer to flowCopyParamsBusinessManagerMock in your tests.