Generally speaking, mocking private and static methods come under the category of unusual mocking. Having said that, there still exists support for Mocking private and static methods by few unit testing frameworks like PowerMockito and not directly by Mockito.
Mockito provides full support for mocking void methods, which we will see with examples in this article. For Mockito, there is no direct support to mock private and static methods. Mockito, in my opinion intentionally does not provide support for these kinds of mocks, as using these kinds of code constructs are code smells and poorly designed code.
Powermock extends capabilities of other frameworks like EasyMock and Mockito and provides the capability to mock static and private methods. For the sake of this article, we are going to write examples with the Mockito extension for power mock.
In order to include the Mockito library in gradle based projects, below are the libraries to be included:. Powermock-api-mockito2 — The library is required to include Mockito extensions for Powermockito. Powermock-module-junit4 — Module is required to include PowerMockRunner which is a custom runner to be used for running tests with PowerMockito.
An important point to note here is that PowerMock does not support Junit5 test runner. Hence the tests need to be written against Junit4 and the tests need to be executed with PowerMockRunner.
Mocking private methods, which are called internally from a method under test can be unavoidable at certain times. For this Example, the class under test is created as a spy instance with mocking on few interface invocations and private method invocation. This annotation tells powerMockito to prepare certain classes for testing. These will be mostly those classes that need to be Bytecode manipulated. Complete Test Sample: Continuing the same example from the previous articles, where priceCalculator has some mocked dependencies like itemService, userService etc.
We have created a new method called — calculatePriceWithPrivateMethod, which calls a private method inside the same class and returns whether the customer is anonymous or not. When a method under test, involves using a static method from the same class or from a different classwe will need to include that class in prepareForTest annotation before the Test or on the test class.
For Example : Suppose you change your password for your internet banking account, once the change is successful you receive notification over your email. Stubbing void methods i. It requires the stub to be set up using the above methods as per the test expectations.
Also, please note that all the void method calls are by default mocked to doNothing. Hence, even if an explicit mock setup is not done on VOID method calls, the default behavior is still to doNothing. For all the examples, let's assume, that there are a class StudentScoreUpdates which has a method calculateSumAndStore.
This method calculates the sum of scores as input and calls a void method updateScores on databaseImplementation instance. For Example : Set up mock like this:. This gives an added verification of arguments that the method was called with. For void methods, mockito provides a special function called doCallRealMethod which can be used when you are trying to set up the mock.
What this will do, is call the real void method with the actual arguments. As shown in the example above, assume both PriceCalculator and DiscountCategoryFinder are final classes that need to be mocked. Both of these can be mentioned as an array of classes in PrepareForTest annotation and can be stubbed in the test method.
If all the tests need to use the same final class, then it makes sense to mention this attribute at test class level which simply means that the prepared class will be available to all the Test Methods. For static and final methods, Mockito does not have an out of box support, but libraries like PowerMockito which heavily inherit a lot of things from Mockito does provide such support and has to actually perform bytecode manipulation in order to support these features.
Mockito out of the box supports stubbing void methods and provides various methods like doNothing, doAnswer, doThrow, doCallRealMethod etc.
Most Frequently asked Mockito Interview Questions are briefed in our next tutorial.Comment 1. If you already read some other blog post about unusual mocking, you can skip prelude via this link.
I was asked to put together examples for how to mock Java constructs well known for their testability issues:. I am calling these techniques unusual mocking. I was worried that such examples without any guidance can be widely used by teammates not deeply experienced in mocking frameworks.
Developers practicing TDD or BDD should be aware of testability problems behind these constructs and try to avoid them when designing their tests and modules. But sometimes you have to extend or maintain legacy codebase that usually contains low cohesive classes.
In most cases there isn't time in the current hectic agile world to make such classes easy to unit test the standard way. When you are trying to unit test such classes, you often realize that unusual mocking is needed. This is my preferred technique when I need to mock private method. They are gathered in this blog post. In my opinion it should be used only in very rare and non-avoidable cases. Source code can be downloaded from Github. Over a million developers have joined DZone. Let's be friends:.
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Mocking Private, Static and Void Methods Using Mockito
Like 3. Join the DZone community and get the full member experience. Join For Free. Foreword If you already read some other blog post about unusual mocking, you can skip prelude via this link. I was asked to put together examples for how to mock Java constructs well known for their testability issues: Mock private method Mock final method Mock final class Mock constructor Mock static method I am calling these techniques unusual mocking.
Mock Private Method Refactoring Considerations Private method that is needed to be mocked can be in: testing class will call it TC direct dependency of testing class will call is DDC class that is not direct dependency of testing module will call it NDDC Re-factoring techniques to consider: If the private method is in TC, it is a good sign that TC has low cohesion has too many responsibilities and logic behind private method should be extracted into separate class.
After this refactoring, private method in TC becomes public in new dependency class. Than it is possible to mock it standard way. Consider moving this logic to TC or to separate module.
Private method than becomes public and can be mocked standard way. If the private method is in NDDC, you are probably creating integration test instead of unit test.If you already read some other blog post about unusual mocking, you can skip prelude via this link. I was asked to put together examples how to mock Java constructs well know for their testability issues:.
I am calling these techniques unusual mocking. I was worried that such examples without any guidance can be widely used by teammates not deeply experienced in mocking frameworks. Developers practicing TDD or BDD should be aware of testability problems behind these constructs and try to avoid them when designing their tests and modules.
But sometimes you have to extend or maintain legacy codebase that usually contains low cohesive classes. When you are trying to unit test such class you often realize that unusual mocking is needed. This is my preferred technique when I need to mock private method. They are gathered in this blog post. In my opinion it should be used only in very rare and non-avoidable cases.
Source code can be downloaded from Github. So if the test is defined in the same package in this case, net. Yes, that is correct.
Mock Private Method
Changing access modifier from private to default is workaround I mentioned in blog post. Your email address will not be published. This site uses Akismet to reduce spam.
In some cases, you may need to alter the behavior of private method inside the class you are unit testing. You will need to mock this private method and make it return what needed for the particular case. Since this private method is inside your class under test then mocking it is little more specific. You have to use spy object. A spy is a real object which mocking framework has access to. Spied objects are partially mocked objects.
Some their methods are real some mocked. I would say use spy object with great caution because you do not really know what is happening underneath and whether are you actually testing your class or mocked version of it.
Below is a simple code that has a private method which created new Point object based on given as argument one. What we want to achieve in the unit test is to mock private method so that each call to it returns an object we have control over.
The full code example is shown below:. PowerMock provides a way to mock private methods by using spy objects. One example is that PowerMock can spy on final objects. Automation Rhapsody Automate with enthusiasm. Mock private method call with PowerMock Last Updated on Post summary: How to mock private method with PowerMock by using spy object.
Mock private method In some cases, you may need to alter the behavior of private method inside the class you are unit testing. Spy object A spy is a real object which mocking framework has access to. Code to be tested Below is a simple code that has a private method which created new Point object based on given as argument one.
The full code example is shown below: import org. Before; import org. Test; import org. RunWith; import org. PowerMockito; import org. PrepareForTest; import org. PowerMockRunner; import static org. Related Posts PowerMock examples and why better not to use them.In test driven development TDD unit testing is a sub part which implies the quality of the implementation.
While doing unit testing using junit you will come across places where you want to mock classes. Mocking is done when you invoke methods of a class that has external communication like database calls or rest calls.
Through mocking you can explicitly define the return value of methods without actually executing the steps of the method. This particular method is invoked inside isPlay method of the same Person class and affects the return value of isPlay method.
So how can we test isPlay without letting runInGround String location execute and talking to the database? Instead of using mock class here we need to use Mockito.
Then we can mock the method we want as follows. Hope this would be helpful. Happy coding with unit testing :D. Further Reading. Sign in. Mocking a method in the same test class using Mockito. Udeshika Sewwandi Follow. Towards Data Science A Medium publication sharing concepts, ideas, and codes. Towards Data Science Follow.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. The problem here is a. In class A you are creating a new B object. So, mock object is never used. To fix this change your Class A implementation to below:.
Learn more. Mockito: Mock a method call inside another method Ask Question. Asked 2 years, 1 month ago. Active 2 years, 1 month ago. Viewed 6k times. Any suggestions on how should I mock b. Mahyar Mahyar 1 1 gold badge 7 7 silver badges 23 23 bronze badges.
You cannot mock objects that are created by your object under test with newsince you have no control over those objects. You would have to make the B a field of class A and then inject it during your test. I will if this is a method call that takes B, to mock this method, or even better, use an ArugmentCaptor to capture the B passed to the method.
Active Oldest Votes. Bikas Katwal Bikas Katwal 1, 1 1 gold badge 10 10 silver badges 22 22 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Programming tutorials can be a real drag. Featured on Meta. Community and Moderator guidelines for escalating issues via new response…. Feedback on Q2 Community Roadmap. Triage needs to be fixed urgently, and users need to be notified upon….
Technical site integration observational experiment live on Stack Overflow.The best ideas are the crazy ones. If you have a crazy idea and it works, it's really valuable. Darren Carr wrote: In the end I started to refactor the first snippet and wow. I opened a can of worms. There was so much code to refactor Ive spent the best part of two days doing it and nearly completed. Forum: Testing. Mocking Method call within a Method? Darren Carter. Hi everyone, Im fairy new with mockito and am trying to write a simple unit test for a rest controller.
However im stuck on one particualr bit. The controller gets an instance of a static class i.Testing private methods using jmockit.
This attribute is only set by event listeners when the application fires up in tomcat. I did not write this code so will be refactoring the way it works using spring security and DI. But in the meantime is there a way in mockito that I can get it to sort of mock the checkStrategyName method? Junilu Lacar. I like Seems to me you're going to have to refactor that line of code in the first snippet first. IMO, there's no point in trying to find a workaround for this; just bite the bullet and refactor first.
James Boswell. As you have already created a mock for LicenseAuthentication, why don't you mock the call to the getLicenseAuthentication method? Surely you would want to do this anyway as LicenseAuthentication is not the class under test.
Hi Guys, Thank you ever so much for the replies! In the end I started to refactor the first snippet and wow. The whole application object model is so tightly coupled its been a real pain sorting it out to use DI. Thanks for your help though! Consider yourself lucky they were just worms and it only took you two days to clean it up! Not that I have anything against worms but I have seen things much more disgusting than that in my day.
Hey Guys, After all that refactoring and simlier to this threadI have another issue that Im not understanding and was hoping someone could help? Do I need to use the ContextConfiguation in my unit test?
Hi everyone, I resolved the problem and posting the solution here to help others. This does not use the configuration that I loaded from the ContextConfiguation annotation i.
So the code: This example uses spring-test-mvc and loads in the servlet context from an xml file and injects mocked objects into the controllers Autowired attributes. It calls a rest service passing in some Json. Boost this thread! Some fun while Overriding equals. Unable to understand : No Last Call on a Mock available.
Testing Spring Controller. Mockito "when" problem. Mockito Help - Problem to sort a List of mock objects.