Suppose I have the following interface:
public interface ISomething {
default int doStuff() {
return 2 * getValue();
}
int getValue();
}
When I now mock this interface like this:
#Mock
private ISomething _something;
#Before
public void setup() {
doCallRealMethod().when(_something).doStuff();
}
and try to test the doStuff() method like the following:
#Test
public void testDoStuff() {
when(_something.getValue()).thenReturn(42);
assertThat("doStuff() returns 84", _something.doStuff(), is(84));
}
I expect the test to succeed, but I get:
org.mockito.exceptions.base.MockitoException:
Cannot call real method on java interface. Interface does not have any implementation!
Calling real methods is only possible when mocking concrete classes.
I tried subclassing ISomething with an abstract class like this:
public abstract class Something implements ISomething {
}
and mock this class like above. With this approach, I get the same.
Does Mockito not support calling default implementations?
That's correct. The current version of Mockito doesn't support this. You could raise a feature request here. Do note that it seems to be related to issue 456 which was fixed in release 1.10.0, so please make sure you test this in the latest version first.
I was working on a project using Mockito 1.9.5 and ran into the same issue that you found. We couldn't upgrade Mockito because of the way our build server worked. The problem we ran into was when we were writing unit tests for the concrete subclasses, as we couldn't stub out or include the default methods from the interface in our mock objects (so slightly different from your example).
Here is an example subclass using your model:
public class ConcreteSomething implements ISomething {
#Override
int getValue()
{
return 42;
}
}
Then in the unit test class, we explicitly made a private inner class. This class overrode all the default methods of the concrete class under test (i.e. ConcreteSomething) with the interface's default implementation. So in this example, something like:
private class ConcreteSomethingDefaultImpl extends ConcreteSomething {
#Override
int doStuff() {
return super.doStuff();
}
}
For us, a mock made using mock(ConcreteSomething.class) couldn't have it's default methods called using doCallRealMethod(), but mock(ConcreteSomethingDefaultImpl.class) could, and more importantly, it was the default implementation code in the interface that was being used.
I hope that helps anyone else who is constrained to use a particular version of Mockito.
Related
Now I have some other library beans that implement initializingBeans and add some time-consuming methods, but I don't want to actually execute them, I need the Spring environment, but this bean I can mock it to reduce the overall test time, what should I do
This is the pseudo code of the bean of Mock：
public final class TimeoutBean implements InitializingBean, ApplicationContextAware, ApplicationListener {
#Override
public void afterPropertiesSet() throws Exception {
initProc();
}
/**
* init
*/
public void initProc() {
//... Something time-consuming and irrelevant to this test
}
}
And my mock unit test code：
#SpringBootTest(classes = Application.class)
#DelegateTo(SpringJUnit4ClassRunner.class)
public class MockTest {
#MockBean
private TimeoutBean timeoutBean;
#Resource
private MyRepository myRepository;
#SneakyThrows
#Test
public void test() {
doNothing().when(timeoutBean).initProc();
myRepository.getById(1L);
}
}
In this way, the Mock initProc method is invalid. I can probably understand because #MockBean calls after InitializingBean#afterPropertiesSet. When the afterPropertiesSet is executed, TimeoutBean is not an Mock object, but I don't know how to solve it.
Your class TimeoutBean is final and mockito cannot mock final classes. So first you will have to fix that. After that I think it should work. For mocked classes you don't have to tell mockito to doNothing() becease that is the default behaviour for mocks.
I don't understand what you mean with: the Mock initProc method is invalid?
I have a DAO implementation class :
public class DataPollingDAOImpl implements DataPollingDAO {
public List<String> getInfo(String id,String columnName)
{
// some code which calls the database and retrieves data.
}
}
I have written a mockito test case as follows-
public class connection{
#Mock private DataPollingDAOImpl myDao;
#Test public void test() {
when(myDao.getInfo("520", "Hole"));
}
}
I created a mock database connection as well. However what shall I do to print success on the console to show a success case after calling myDao.getInfo() in test method?
If you are mocking using #Mock then I suppose you want your mock to return a value, you specify how to return the value by:
when(myDao.getInfo(anyString(), anyString()).thenReturn(Arrays.asList("yourReturnValue"));
If you want to see if you have called your Mock, then normally #Spy is used and you write:
Mockito.verify(myDao).getInfo(anyString(),anyString());
And I do recommend you to use interfaces (as DataPollingDAO) and not implementations (DataPollingDAOImpl)
I've an interface like this:
public interface ICustomer extends IEnd<Customer> {
String getId();
ICustomer id(String id);
ICustomer email(String email);
ICustomer description(String description);
}
I need to mock any methods which returns an ICustomer regardless of parameters.
When these methods are called, the self called ICustomer have to be returned.
Any ideas?
To do this you need a custom Answer class:
public class CustomerAnswer implements Answer {
#Override
public Object answer(InvocationOnMock invocation) throws Throwable {
Class retType = invocation.getMethod().getReturnType();
if (ICustomer.class.isInstance(retType)) {
return invocation.getMock();
}
// provide default logic here -- override with "when()" calls.
return null;
}
}
Then create your mock, specifying the default behavior:
Foo mockCustomer = mock(ICustomer.class, new CustomerAnswer());
Add, when() statements for other methods that need to be stubbed.
But as I commented in the OP, be sure you actually want to mock this class before you go thru all the trouble. Only mock when it will make the test code simpler. If you have some simple implementation of the interface that is just a POJO with fluent API (no side-effects, no complicated dependencies or injections), there is probably no need to mock it. Instead use a real instance, because the real instance already returns the original object.
If you need to verify() on the ICustomer object, then use a #Spy of a real instance of a ICustomer.
How to bind mock of final class in Jukito ?
For example :
public final class SomeFinalClass(){
public SomeFinalClass(String someString){
}
}
//Testing class
#Runwith(JukitoRunner.class)
public class TestingClass(){
#Inject
private SomeFinalClass someFinalClassMock;
public static class TestModule extends JukitoModule {
#Override
protected void configureTest() {
// bind(SomeClient.class).in(TestSingleton.class);
}
#Provides
public SomeFinalClass getSomkeFinalClass() {
return Mokito.mock(SomeFinalClass.class); //throws error
}
}
}
Is there a way i can use PowerMockito with JukitoRunner ?
You can mock a final class if you're using Mockito 2. From Mockito 2 Wiki:
Mocking of final classes and methods is an incubating, opt-in feature. It uses a combination of Java agent instrumentation and subclassing in order to enable mockability of these types. As this works differently to our current mechanism and this one has different limitations and as we want to gather experience and user feedback, this feature had to be explicitly activated to be available ; it can be done via the mockito extension mechanism by creating the file src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker containing a single line: mock-maker-inline.
After you created this file, Mockito will automatically use this new engine and one can do :
final class FinalClass {
final String finalMethod() { return "something"; }
}
FinalClass concrete = new FinalClass();
FinalClass mock = mock(FinalClass.class);
given(mock.finalMethod()).willReturn("not anymore");
assertThat(mock.finalMethod()).isNotEqualTo(concrete.finalMethod());
I'm new on using ninject and Dependency Injection, and have a problem using it.
I try to using Ninject on my class libray, and building an integration tests.
now, I see in many example that, for using ninject is just specified the DI Module like this:
Public Class DIModule : NinjectModule
public override void Load()
{
Bind<IUSAServices>().To<USAServices>();
}
And then on my test class, I try to call my dependency is like this:
[TestClass]
public class USAIntegrationTests
{
private readonly IUSAServices _usaService;
public USAIntegrationTests(IUSAServices usaServices)
{
_usaService = usaServices;
}
[TestMethod]
public void ValidateUserTests()
{
Assert.IsTrue(_usaService.ValidateUser("username1", "password1"));
}
}
And Getting this error:
Unable to get default constructor for class USATests.IntegrationTests.USAIntegrationTests.
However I read the documentation and tried like this:
[TestClass]
public class USAIntegrationTests
{
private readonly IUSAServices _usaService;
public USAIntegrationTests()
{
using (IKernel kernel = new StandardKernel(new DIModule()))
{
_usaService = kernel.Get<IUSAServices>();
}
}
[TestMethod]
public void ValidateUserTests()
{
Assert.IsTrue(_usaService.ValidateUser("mantab", "banget"));
}
}
The test is works properly.
My question is, why I getting that error? is that some way to get around it?
Thanks in advance.
Unit test frameworks require your test classes to have a default constructor. You usually can't integrate DI containers with them. Instead of using constructor injection, you will have to call the container directly from your code, although for unit tests you should typically not have a container at all (for integration tests however, this is okay).
You can add a paramterless constructor for the class. It worked for me.