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 am getting InvalidUseOfMatchersException on a different test than the one using Matchers
The below two tests are running fine individually but when running together, after the first test passes successfully, second test is failing and throwing InvalidUseOfMatchersException pointing to first test
#Test(expected = InputException.class)
public void shouldThrowExceptionWhenInputNull() {
calculator.calculateA(any(), any(), any(),eq(null));
}
#Test
public void testCalculateB() {
assertTrue(BigDecimal.valueOf(8000).compareTo(calculator.calculateB(12)) == 0);
}
This is the exception in stack trace
org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Misplaced or misused argument matcher detected here:
TestClass.shouldThrowExceptionWhenInputNull
According to the exception, first test should fail but its passing and second test is failing. Individually both these tests are passing successfully
calculator.calculateA(any(), any(), any(), eq(null));
This isn't a valid use of Matchers. Mockito only uses any and eq when used with when or verify, as a means of matching invocations that tell Mockito what to return or what calls should have been recorded. You'll need to call calculateA with specific values, such as calculator.calculateA(1, 2, 3, null);.
Mockito matchers work via side effects, so the only time that Mockito can throw an exception is the next time you interact with Mockito. This might be another method, but you can help ensure that those are local by using MockitoRule, MockitoJUnitRunner, or by adding a call to validateMockitoUsage from an #After method:
#After public void validateMockito() {
Mockito.validateMockitoUsage();
}
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);
}
}
I have a problem with Spock Mock() object.
I have a java class I'm trying to test. This class does some ftp stuff I want to mock.
My sample code
class ReceiveDataTest extends Specification{
String downloadPath = 'downloadPath';
String downloadRegex = 'downloadRegex';
SftpUtils sftpUtils = Mock();
ReceiveData receiveData;
def setup(){
sftpUtils.getFileNames(downloadPath,downloadRegex) >> ['file1', 'file2']
receiveData= new ReceiveData()
receiveData.setDownloadPath(downloadPath)
receiveData.setDownloadRegex(downloadRegex)
receiveData.setSftpUtils(sftpUtils);
}
def "test execute"() {
given:
def files = sftpUtils.getFileNames(downloadPath,downloadRegex)
files.each{println it}
when:
receiveData.execute();
then:
1*sftpUtils.getFileNames(downloadPath,downloadRegex)
}
}
public class ReceiveData(){
//fields, setters etc
public void execute() {
List<String> fileNames = sftpUtils.getFileNames(downloadPath, downloadRegex);
for (String name : fileNames) {
//dowload and process logic
}
}
}
Now, inside "test execute" the files.each{} prints what is expected. But when receiveData.execute() is called my sftpUtils are returning null..
Any ideas why?
EDIT
Maybe i didnt state my problem well - that I dont want to just check if getFileNames was called. I need the result to proper check the for loop. If I comment the loop inside execute, the test passes. But since I use the result of the getFilenames() method, I get a NPE execute method reaches the for loop. With mockito I would do something like this
Mockito.when(sftpUtils.getFilenames(downloadPath, downloadRegex)).thenReturn(filenamesList);
receiveData.execute();
Mockito.verify(sftpUtils).getFilenames(downloadPath, downloadRegex);
//this is what I want to test and resides inside for loop
Mockito.verify(sftpUtils).download(downloadPath, filenamesList.get(0));
Mockito.verify(sftpUtils).delete(downloadPath, filenamesList.get(0));
but I cannot use Mockito.verify() inside Spock then block
The main problem is that you did not include the response generator (the >> part) in the expectation (i.e. the "1 * ..." part inside the then: block).
This is explained well in the spock documentation.
http://spockframework.org/spock/docs/1.0/interaction_based_testing.html#_combining_mocking_and_stubbing
https://spock-framework.readthedocs.org/en/latest/interaction_based_testing.html#wheretodeclareinteractions
You shouldn't have to declare your stub in the setup: block. You can just specifiy it once in the then: block -- even though that follows the call to receiveData.execute(). That's part of the magic of spock thanks to Groovy AST transformations. And since (non-shared) fields are reinitialized before each test (more AST based magic), you don't even need setup() in this case.
Another odd thing is that you are both stubbing out sftpUtils.getFilenames() and also calling it from the test code. Mocks and stubs are intended to replace collaborators that are called from the system under test. There's no reason to call the stub from the test driver. So delete the call to getFilenames() from your given block and let the code under test call it instead (as it does).
Groovy lets you simplify calls to Java set and get methods. Look at the initialization of receiveData below. Its okay to use def in Groovy. Let the compiler figure out the data types for you.
Leading to something like:
class ReceiveDataTest extends Specification {
// only use static for constants with spock
static String PATH = 'downloadPath'
static String REGEX = 'downloadRegex'
def mockSftpUtils = Mock(SftpUtils)
def receiveData = new ReceiveData(downloadPath : PATH,
downloadRegex : REGEX,
sftpUtils : mockSftpUtils)
def "execute() calls getFileNames() exactly once"() {
when:
receiveData.execute()
then:
1 * mockSftpUtils.getFileNames(PATH, REGEX) >> ['file1', 'file2']
0 * mockSftpUtils.getFileNames(_,_)
// The second line asserts that getFileNames() is never called
// with any arguments other than PATH and REGEX, aka strict mocking
// Order matters! If you swap the lines, the more specific rule would never match
}
}
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.