I'm using Mockito 1.9.0. I want mock the behaviour for a single method of a class in a JUnit test, so I have
final MyClass myClassSpy = Mockito.spy(myInstance);
Mockito.when(myClassSpy.method1()).thenReturn(myResults);
The problem is, in the second line, myClassSpy.method1() is actually getting called, resulting in an exception. The only reason I'm using mocks is so that later, whenever myClassSpy.method1() is called, the real method won't be called and the myResults object will be returned.
MyClass is an interface and myInstance is an implementation of that, if that matters.
What do I need to do to correct this spying behaviour?
Let me quote the official documentation:
Important gotcha on spying real objects!
Sometimes it's impossible to use when(Object) for stubbing spies. Example:
List list = new LinkedList();
List spy = spy(list);
// Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
when(spy.get(0)).thenReturn("foo");
// You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);
In your case it goes something like:
doReturn(resultsIWant).when(myClassSpy).method1();
In my case, using Mockito 2.0, I had to change all the any() parameters to nullable() in order to stub the real call.
My case was different from the accepted answer. I was trying to mock a package-private method for an instance that did not live in that package
package common;
public class Animal {
void packageProtected();
}
package instances;
class Dog extends Animal { }
and the test classes
package common;
public abstract class AnimalTest<T extends Animal> {
#Before
setup(){
doNothing().when(getInstance()).packageProtected();
}
abstract T getInstance();
}
package instances;
class DogTest extends AnimalTest<Dog> {
Dog getInstance(){
return spy(new Dog());
}
#Test
public void myTest(){}
}
The compilation is correct, but when it tries to setup the test, it invokes the real method instead.
Declaring the method protected or public fixes the issue, tho it's not a clean solution.
The answer by Tomasz Nurkiewicz appears not to tell the whole story!
NB Mockito version: 1.10.19.
I am very much a Mockito newb, so can't explain the following behaviour: if there's an expert out there who can improve this answer, please feel free.
The method in question here, getContentStringValue, is NOT final and NOT static.
This line does call the original method getContentStringValue:
doReturn( "dummy" ).when( im ).getContentStringValue( anyInt(), isA( ScoreDoc.class ));
This line does not call the original method getContentStringValue:
doReturn( "dummy" ).when( im ).getContentStringValue( anyInt(), any( ScoreDoc.class ));
For reasons which I can't answer, using isA() causes the intended (?) "do not call method" behaviour of doReturn to fail.
Let's look at the method signatures involved here: they are both static methods of Matchers. Both are said by the Javadoc to return null, which is a little difficult to get your head around in itself. Presumably the Class object passed as the parameter is examined but the result either never calculated or discarded. Given that null can stand for any class and that you are hoping for the mocked method not to be called, couldn't the signatures of isA( ... ) and any( ... ) just return null rather than a generic parameter* <T>?
Anyway:
public static <T> T isA(java.lang.Class<T> clazz)
public static <T> T any(java.lang.Class<T> clazz)
The API documentation does not give any clue about this. It also seems to say the need for such "do not call method" behaviour is "very rare". Personally I use this technique all the time: typically I find that mocking involves a few lines which "set the scene" ... followed by calling a method which then "plays out" the scene in the mock context which you have staged... and while you are setting up the scenery and the props the last thing you want is for the actors to enter stage left and start acting their hearts out...
But this is way beyond my pay grade... I invite explanations from any passing Mockito high priests...
* is "generic parameter" the right term?
One more possible scenario which may causing issues with spies is when you're testing spring beans (with spring test framework) or some other framework that is proxing your objects during test.
Example
#Autowired
private MonitoringDocumentsRepository repository
void test(){
repository = Mockito.spy(repository)
Mockito.doReturn(docs1, docs2)
.when(repository).findMonitoringDocuments(Mockito.nullable(MonitoringDocumentSearchRequest.class));
}
In above code both Spring and Mockito will try to proxy your MonitoringDocumentsRepository object, but Spring will be first, which will cause real call of findMonitoringDocuments method. If we debug our code just after putting a spy on repository object it will look like this inside debugger:
repository = MonitoringDocumentsRepository$$EnhancerBySpringCGLIB$$MockitoMock$
#SpyBean to the rescue
If instead #Autowired annotation we use #SpyBean annotation, we will solve above problem, the SpyBean annotation will also inject repository object but it will be firstly proxied by Mockito and will look like this inside debugger
repository = MonitoringDocumentsRepository$$MockitoMock$$EnhancerBySpringCGLIB$
and here is the code:
#SpyBean
private MonitoringDocumentsRepository repository
void test(){
Mockito.doReturn(docs1, docs2)
.when(repository).findMonitoringDocuments(Mockito.nullable(MonitoringDocumentSearchRequest.class));
}
Important gotcha on spying real objects
When stubbing a method using spies , please use doReturn() family of methods.
when(Object) would result in calling the actual method that can throw exceptions.
List spy = spy(new LinkedList());
//Incorrect , spy.get() will throw IndexOutOfBoundsException
when(spy.get(0)).thenReturn("foo");
//You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);
I've found yet another reason for spy to call the original method.
Someone had the idea to mock a final class, and found about MockMaker:
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
Source: https://github.com/mockito/mockito/wiki/What%27s-new-in-Mockito-2#mock-the-unmockable-opt-in-mocking-of-final-classesmethods
After I merged and brought that file to my machine, my tests failed.
I just had to remove the line (or the file), and spy() worked.
One way to make sure a method from a class is not called is to override the method with a dummy.
WebFormCreatorActivity activity = spy(new WebFormCreatorActivity(clientFactory) {//spy(new WebFormCreatorActivity(clientFactory));
#Override
public void select(TreeItem i) {
log.debug("SELECT");
};
});
As mentioned in some of the comments, my method was "static" (though being called on by an instance of the class)
public class A {
static void myMethod() {...}
}
A instance = spy(new A());
verify(instance).myMethod(); // still calls the original method because it's static
Work around was make an instance method or upgrade Mockito to a newer version with some config: https://stackoverflow.com/a/62860455/32453
Bit late to the party but above solutions did not work for me , so sharing my 0.02$
Mokcito version: 1.10.19
MyClass.java
private int handleAction(List<String> argList, String action)
Test.java
MyClass spy = PowerMockito.spy(new MyClass());
Following did NOT work for me (actual method was being called):
1.
doReturn(0).when(spy , "handleAction", ListUtils.EMPTY_LIST, new String());
2.
doReturn(0).when(spy , "handleAction", any(), anyString());
3.
doReturn(0).when(spy , "handleAction", null, null);
Following WORKED:
doReturn(0).when(spy , "handleAction", any(List.class), anyString());
I want to mock below method chain using easymock-powermock,
OtherClass oc = SampleClass.getInstance().getSampleMethod(new StringReader("ABC");
getInstance () is a singleton method.
getSampleMethod() is a public method.
When I try to use expect/andReturn getting null.
I am not sure if you are setting the expectations at once to the whole method chain but that is not how it works. You have to set the expectation for each and every method call separately.
In your case, as first method call is a static call you should use powermock and set the expectation and return the mocked instance for it. Then you should add the expectation for second method call. I have given the sample code below Please check if it works in your case.
#RunWith(PowerMockRunner.class)
#PrepareForTest({SampleClass.class})
public class SimpleClassTest{
#Test
public void test(){
PowerMock.mockStatic(SampleClass.class);
SampleClass sampleClassInstance = EasyMock.createMock(SampleClass);
EasyMock.expect(SampleClass.getInstance).andReturn(sampleClassInstance);
EasyMock.expect(sampleClassInstance.getSampleMethod(/*required parameter goes here*/).andReturn(/*Otherclass instance goes here*/);
PowerMock.replayAll();
EasyMock.replay(sampleClassInstance);
}
}
There is a local instance of a class being instantiated inside a method.
eg
class TestMe{
public void foo()
{
A a = new A();
a.setState(this);
}
}
class A
{
private B b;
public void setState(TestMe tm)
{
b.doSomething(); //returns void
b.doSomethingAdditional(); //returns void
}
}
When testing foo, using powerMock, I wanted to do a verify to ensure that methods doSomething() and doSomethingAdditional() are called. I was looking something along the lines of the Mockito.verify(ObjectName).functionName() to do. Any suggestions??
PowerMock works in combination with Mockito. You should still have all the functionality to verify using Mockito calls.
Once you mock B, when you mock its functions and then pass it into A you can use the Mockito.verify.
verify(mockBObject).doSomething();
verify(mockBObject).doSomethingAdditional();
This may need a few extra steps to hook your mock object into A, since you don't have a constructor where you can define B passed in, or have some constructor to hook into. If you are just having A initialize B at the creation of A, you can use some PowerMockito tools to tell it what to do. Just mocking B will not do, because when your A is setup, it doesn't know to use your mocked object in its code as the B internal.
PowerMockito.whenNew(B.class).withNoArguments().thenReturn(mockBObject);
As of right now B is never setup or initialized, so it could cause some issues. If B is a static singleton object that you are assuming is created somewhere else, you can do similar mocking of the static getInstance() call to return a mock of B.
How to mock Runnable here using PowerMock.... here initialize () calls some two other methods.
Can you please clarify how this can be done? searched for almost 2days..
Please try these steps:
Use the #RunWith(PowerMockRunner.class) annotation at the class-level of the test case.
Use the #PrepareForTest(ClassThatCreatesTheNewInstance.class) annotation at the class-level of the test case.
Use PowerMock.createMock(NewInstanceClass.class) to create a mock object of the class that should be constructed (let's call it mockObject).
Use PowerMock.expectNew(NewInstanceClass.class).andReturn(mockObject) to expect a new construction of an object of type NewInstanceClass.class but instead return the mock object.
Use PowerMock.replay(mockObject, NewInstanceClass.class) to change the mock object and class to replay mode, alternatively use the PowerMock.replayAll() method.
Use PowerMock.verify(mockObject, NewInstanceClass.class) to change the mock object and class to verify mode, alternatively use the PowerMock.verifyAll() method.
Reference: https://code.google.com/p/powermock/wiki/MockConstructor
I have a service class which has overloaded constructors. One constructor has 5 parameters and the other has 4.
Before I call,
var service = IoC.Resolve<IService>();
I want to do a test and based on the result of this test, resolve service using a specific constructor. In other words,
bool testPassed = CheckCertainConditions();
if (testPassed)
{
//Resolve service using 5 paramater constructor
}
else
{
//Resolve service using 4 parameter constructor
//If I use 5 parameter constructor under these conditions I will have epic fail.
}
Is there a way I can specify which one I want to use?
In general, you should watch out for ambiguity in constructors when it comes to DI because you are essentially saying to any caller that 'I don't really care if you use one or the other'. This is unlikely to be what you intended.
However, one container-agnostic solution is to wrap the conditional implementation into another class that implements the same interface:
public class ConditionalService : IService
{
private readonly IService service;
public ConditionalService()
{
bool testPassed = CheckCertainConditions();
if (testPassed)
{
// assign this.service using 5 paramater constructor
}
else
{
// assign this.service using 4 parameter constructor
}
}
// assuming that IService has a Foo method:
public IBaz Foo(IBar bar)
{
return this.service.Foo(bar);
}
}
If you can't perform the CheckCertainConditions check in the constructor, you can use lazy evaluation instead.
It would be a good idea to let ConditionalService request all dependencies via Constructor Injection, but I left that out of the example code.
You can register ConditionalService with the DI Container instead of the real implementation.
My underlying problem was that I was trying to resolve my class which had the following signature:
public DatabaseSchemaSynchronisationService(IDatabaseService databaseService, IUserSessionManager userSessionManager)
This was basically useless to me because my usersessionmanager had no active NHibernate.ISession because a connection to my database had not yet been made. What I was trying to do was check if I did have a connection and only then resolve this class which served as a service to run database update scripts.
When changing my whole class to perform the scripts in a different way, all I needed in its constructor's signature was:
public DatabaseSchemaSynchronisationService(ISessionFactory sessionFactory)
This allowed me to open my own session. I did, however have to first check if the connection was ready before attempting to resolve the class, but having IDatabaseSchemaSynchronisationService as a parameter to another class's constructor; this class also gettting resolved somewhere where I could not check the db connection was a bad idea.
Instead in this second class, I took the IDatabaseSchemaSynchronisationService paramater out of the constructor signature and made it a local variable which only gets instantiated (resolved) :
if (connectionIsReady)
Thanks to everyone who answered.