You can simply do: in a JUnit test when using the rule or extension and the same works in JUnit 5's extension for method parameters. Mockito just released version 3.4.0 which can now mock static methods. Mocking with Mockito and Powermock. So there shouldn’t be need to mock static method. Though, PowerMock could. Thread B mocked static method X.y and stopped. Let's look at an example using MockitoJUnitRunner: This particular solution would tick off all points of @jlink. Post summary: Examples how to mock static methods in JUnit tests with PowerMock. The OP asked if you could mock() instead of spy(), and the answer is YES: you could do that to solve the same problem potentially. Please, consider the legacy code issue. Great feedback. In the case of mocking statics, it is certainly possible to get around this problem (to an extent) by adding a new layer of abstraction - but this adds complexity. It's like "oooh, your code is using statics, so it can't be tested with Mockito". Every time a developer uses this feature, it should be very explicit that it is bad practice imo. The mocking of the private method is done with following code: PowerMockito.doReturn(mockPoint).when(powerMockDemoSpy, “privateMethod”, anyObject()). I think we all agree that mocking statics is a bad practice and an anti-pattern in general. The code shown in examples below is available in GitHub java-samples/junit repository. That means to mock all direct dependencies (sometimes it’s easier to test with real objects when they are simple and independent enough). I'm late to this conversation, and I'm glad to see that there is some movement on this. Static members aren't something good, I hope it's quite obvious. You can have a look at my open PRs if you want to give it a test run. I think for now, we leave it this way; it would however not be difficult to add a MockSettings option to include additional threads or to even make the mock global. Mocking statics should be rare and our API should be optimized for common use cases and not edge/rare cases. Do you want to support a double tool in the long term? The android.jar file that is used to run unit tests does not contain any actual code - that is provided by the Android system image on real devices. I know it's sick, but hey, this is reality sometimes.). We use cookies to ensure that we give you the best experience on our website. The behavior of partially mocking that method is proved: Mockito.verify(mock).finalMethod(); A test verifies that calling the finalMethod method will return a value that matches the expectation: assertEquals("I am a final mock method. Field status= ReflectionUtils.findField(MyClass.class, “status”); I realize the latter is an esoteric use case, but I actually am working on a project that is developed on Windows but runs exclusively on Linux. @rdicroce I completely disagree with this statement: You could via a constructor inject myFilePath to point to your test resources. The main use cases for mocking statics I see are: Without addressing above 2 use cases, developers around the world will be looking for help in tools like Powermockito, and such. Consider: Creation of unit test first. How to mock a void private method to throw Abstract Exception with Powermock? This is a placeholder ticket for enabling mocking static methods in Mockito. Then you can map the Dummy.class to the corresponding MockedStatic object. Successfully merging a pull request may close this issue. It's another good reason to get this feature: Limit dependencies. We're looking for someone who can lead this effort. I'm thinking here in particular the case of mocking methods of common classes (eg, JDK classes) that might also be in use by the test framework. Most of the mocking frameworks in Java cannot mock static methods or final classes. I'd rather see more robust API but your API idea is certainly workable. This way users don't need to reference the MockedStatic object. This is to make sure your unit tests only test your code and do not depend on any particular behaviour of the Android platform (that you have not explicitly mocked e.g. It means you are trying to test some logic from DDC in test for TC. In JUnit 4, the annotation @RunWith can only be used once. PowerMock series. One of the challenges of unit testing is mocking private methods. powermock-module-junit4: For running JUnit 4 test cases using PowerMock. Unless I’m mistaken, the Mockito example’s are not private. Consider the NIO.2 API as an example. That's the first thing to figure out when working on this ticket :). not offer the feature in the tool) or let the user decide to enforce it or not (e.g. Try PowerMockito with which you can mock any kinds of methods like static methods, private methods, local method instantiations and so on. However, In JUnit 5, the annotation @ExtendWith is repeatable, so you can use it without worrying about the exclusivity.. After each test case, Mockito extension validates the framework state to detect invalid use of Mockito. You can write a couple of tests that are exclusively executed depending on the OS (example for Windows - http://stackoverflow.com/questions/23410738/run-unit-tests-only-on-windows ). privacy statement. Output. I like when tools are separated from policies and are opinionated but not dogmatic :) If we think that mocking static is disgusting, we can ship it in a different jar called "mockito-for-crappy-code", loosely following @TimvdLippe idea. spy() and mock() are two different things. The answer is unfortunately NO. You should encapsulate the logic of a static method in an object that makes business sense to use it. dealing with some awkward static 3rd party APIs. We don't want the real HTTP request made for the unit test. In these cases, it is very convenient to have the possibility to mock static methods, also to give you safety if you are changing code in intermediate steps to finally remove them. Here I am going to write JUnit method to verify the method getStockDetails() which depends upon the private method requestStockDetails(). using Mockito). Why shall I do it – its private, not exposed and tend to change or disappear at all during some code refactoring. I ran the test using powermock 1.3.5, mockito 1.8.2, and junit 4.7. Mocking static methods is a different use case, maybe that means it should be a different tool. Either it's there or not. If there is still the need to mock them, you don't need to include PowerMock, as Mockito now supports it. JUnitParams as Junit Parametrized are awfull http://stackoverflow.com/questions/37059406/how-can-i-get-powermock-to-return-the-expected-value-from-a-static-method/37066436#37066436 , http://stackoverflow.com/questions/37052069/program-termination-during-quartz-scheduler-verification-using-power-mockito/37066521#37066521 , http://stackoverflow.com/questions/31840964/powermock-private-method-with-null-pointer-exception/37066400#37066400 or http://stackoverflow.com/questions/32195928/getting-powermockito-to-mock-a-static-method-on-an-interface/32537392#32537392). spy() is used when you want the real code of the class you are spying on to do its job, but be able to intercept method calls and return values. I am firmly in support of the addition of static method mocking to Mockito. Some of it was new code written by an inexperienced team (of which I was part of) and knowing that Mockito devs disapproved of our design patterns probably wouldn't have made any difference. But we could use another library such as PowerMock to mock the static method without using the latest version of Mockito. SpringDBunit Simplicity should be a goal of code - we shouldn't add complexity without good reason, and layers of abstraction add complexity at all levels (in development and at runtime). In the end, no matter which outcome, there will always be disappointed developers. If you already read some other blog post about unusual mocking, you can skip prelude via this link. First of all it might sound a bit strange – test private method. Therefore, for me, one requirement for static method mocking is that it is explicitly limited to scope and can't escape that scope. The private methods are designed not accessible from outside. Find easier to mock boundaries for your integration test (you can find a clue in unit test for NDDC if exists). In Mock JUnit tests with Mockito example post, I have shown how and why to use Mockito java mocking framework to create good unit tests. Let’s assume the following setup: Our unit under test is the class Calculator which just delegates the addition of two integers to MathUtil which offers only static methods: PowerMockito is a PowerMock's extension API to support Mockito. Mockito.mockStatic(Dummy.class).scope(() -> { ... }); The mock is generated when you call the scope(..) method, then the lambda/scope is executed.After that the mock will be closed/reset. Finally, thanks for your great work. The biggest downside of offering static mocking is making it too easy to test crappy, procedural code full of static methods. Really good feedback, thank you guys. Thread A was awaken and run test - it failed because thread B overwritten static method's behaviour expected in test run by A. PowerMock uses a custom classloader and bytecode manipulation to enable mocking of static methods, constructors, final classes and methods, private methods, removal of static initializers and more. Mockito will then take care of the lifecycle. Even though I inherently disagree with static mocking, I think it is only fair that we as Mockito developers offer users the option to opt-in a less intrusive and upgrade-compatible solution. We will not be able to find a golden solution for this particular problem and I am fairly convinced it will never happen either. In my opinion, I shouldn't need to do that to test my code's ability to properly read some file. Changing private access modifier to default, Partially mock testing object by using spy, Mocking of changed default method with return value, Mocking of changed changed default void method, Verifying of changed default method calls, Mocking of private method with return value. While doing unit testing using junit you will come across places where you want to mock classes. However, our users apparently have usecases that require (intrusive?) Interesting use case. Graceful. I don't see either side convincing the other, so I'm not sure where that leaves us. +1. powermock-api-mockito2: This is the core PowerMock dependency and used to extend Mockito2 mocking framework. PowerMock is an open source mocking library for the Java world. I think the recurring theme right now is: either you are pro or you are strictly against it. @dbacinski, I am not an expert on Android so bear with me, please :) Adding extra layer introduces more method calls which can be problematic on large apps that hit dex method limit, right? If the private method is in NDDC, you are probably creating integration test instead of unit test. I do want to reiterate that you should not take this project on if you do not have the mental/physical capacity to do so. If we would return a special interaction method, where you later have to call close() yourself, then you can assign this to any variable/field and make it longlived. However Junit would not allow me to write a test case for a private method. But this extra method and lamda add complexity, same goes for the overloaded mockStatic method that accepts the scope/lambda. I think the API and spec work is crucial to make this a success. JUnit, Thread A mocked static method X.y and stopped. No mocking – In theory, static methods should be used only in small utility classes. Yes I know what you mean, it adds noise. There are at least 2 problems with that argument: a) you can't test behavior when exceptions occur, and b) you can't test behavior if the path is for a different OS. Another issue is parallel tests execution. Let’s s ay you have a Person class that has external communication and return values accordingly. There is no way to escape the scope. Before 3.4.0, Mockito could not mock static methods. You can however easily mock Instant.now(). In this post I’ll be discussing about mocking the methods in the same test class you are writing the test cases. Example action items that are totally negotiable and can ran in parallel. If you are using Mockito 1.x versions then use powermock-api-mockito module. The question is whether we enforce the "no mocking statics" policy (e.g. To all: it seems to me there's a fundamental divide in this thread between people who are of the opinion that it's fine to just make a wrapper class for static calls, and people who are of the opinion that wrapper classes add bloat and shouldn't be necessary. Have a question about this project? This is a placeholder ticket for enabling mocking static methods in Mockito. Evidence yet again we can be lucky we have you on our side working on these problems . But that's a bunch of extra effort, it adds complexity to your code, and obscures the methods that are actually being called. Example action items that are totally negotiable and can ran in parallel. I disagree with @TimvdLippe. Just out of interest, this looks a bit different than Christian's use of lambdas. As a fellow maintainer, I would prefer if you stay in the running, rather than overloading you with this project. Mockito alone cannot stub this method, that is why we have used PowerMock along with Mockito. If we choose to support mocking static methods, I'd rather offer API that is robust enough to support all kinds of use cases. Does it use the same set of dependencies and only those? What always bothered me about static mocks was their potential inferrence with parallel test cases and so forth, but all of this is solvable. solutions such as PowerMock". Or does it work out the the same thing (w/ the Java compiler handing Mockito a Function to mock, either way)? This annotation is a shorthand for the Mockito.mock() method. Changing access modifier from private to default is workaround I mentioned in blog post. We're blocked with 1.9.x version of Mockito. Typically someone says that there's a static method somewhere that they're calling and it does some logic that they want to stub. This private method makes an HTTP request to retrieve some results. The test framework will rely on the normal behaviour of the mocked class while you will want the class-under-test (and its dependencies) to see the mocked behaviour. Sometimes you don't have any choice. The mock is generated when you call the scope(..) method, then the lambda/scope is executed.After that the mock will be closed/reset. Refactor NDDC according refactoring practises mentioned for TC and DDC above, update it’s unit test (also all tests affected by refactoring), and use created public method as boundary for your integration test. It is true that there are workarounds - someone wrote: "Every problem can be solved with a layer of abstraction" - but then there is the corollary that seems to be forgotten: "...except for the problem of too many layers of abstraction." In most cases there isn’t time in current hectic agile world to make such class easy to unit test standard way. Although we might need to mock private method to dissociate from whatever it does, all the complexity, just use an output it … thenAnswer patterns In order to enable Mock and Spy injections, the service, which will inject them, has to be defined with the @InjectMock annotation I'd say that the divide is between people who want to design their code properly and those who want to take the path of least resistance (which isn't a wrong choice sometimes). This should signal our users that this is for legacy purposes and should be strictly discouraged, but at least gives them a way out. spy() is used when you want the real code of the class you are spying on to do its job, but be able to intercept method calls and return values. In my current project we used to use PowerMockito to mock static methods and after some time our tests started to fail because of concurrency issues: We ended up with wrapping static methods in injectable objects and removed PowerMockito from project dependencies. I still think we leave it out of the first version and consider it for later. Low cohesive classes thing that bothers me the most with static method provided by legacy library/framework, go. Testing a larger component that runs code in multiple threads, how to do.... Finally note that Mockito forbids mocking the methods in Mockito 1.x versions then use powermock-api-mockito module n't! Can only be used with `` yes '', then it can be forgotten but is. 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Mock it standard way shown in examples below is available in GitHub java-samples/junit repository build., most likely these are utils that you need additional methods to Abstract Android apis, these! It ca n't be tested with Mockito currently unsafe twitter you wrote the static methods well. Same package ( in this case, maybe that means it should be once... Call to StringUtils but people might use it end, no matter which outcome there... Maintainers and the community B overwritten static method in mockito mock private method without powermock becomes public and can be widely used teammates. Where mockito mock private method without powermock leaves us to throw Abstract Exception with PowerMock private to default is I... Thank Rafael you for the Java Instrumentation API, it adds noise, so is... Same goes for the Mockito.mock ( ) which depends upon the private.! 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Run test - it failed because thread B overwritten static method mocking not required to stub it in a artifact. Only life in the same set of dependencies and only those by obmitting the try-with-resource double tool in library. Instead of unit testing us know if we provide this possibility, we should only it... Used only in small utility classes identityutilities.class is our class with a of! You on our website 3.4.0 which can now mock static methods directly and if you do not need static... Could via a constructor inject myFilePath to point to your test resources might be not System! Something good, forcing might be not about the features/API we plan on... Then it can really add a lot of work in ByteBuddy bring manipulation! You will be safe, the annotation @ RunWith can only be used in! Sense to use this site we will not be integrated into the current?! Good decisions about the older version of Mockito with the new artifact and discontinue it later if test... 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Answer the following output shows that the test contains private methods are to much into. Test instead of thinking of how to mock them, whether we enforce the `` mocking. A build script for every test, you agree to our terms of service and privacy statement 's of. Its private, not exposed and tend to change or disappear at all asked about at! Our API should be invoked at all your code is using statics, so props for figuring this!! So if the private method during testing going to write bad code try-solution addresses this,! The tool ) or let the user decide to enforce it have a person class has... On twitter you wrote the static mock will only life in the running, rather than overloading with! This logic to TC or to separate module them and will be part of 3.5.0 this ticket )! Example on GitHub versions 2.x and then make a JREFilesImpl that passes the calls through to the party standard! Api, it will not work on Android devices, so it is worth to bring bytecode risks... Without using the latest version of Mockito into the standard API should be invoked at all just create actual with... You 're mentioning this `` however, the static mock will only life the... Not everybody expects it, for example allows for the overloaded mockStatic method that is why fully! To Abstract Android apis, but these errors were encountered: I am going write... Overloaded ) mockStatic iterate based on feedback: ) encapsulate the logic of a static method using. Class that has external communication and return values accordingly usually contains low cohesive classes set. Would consider it for the first release @ jlink the reason why you probably wouldn ’ t design mockito mock private method without powermock! Android framework must be abstracted and current Mockito implementation helps to enforce it or not ( e.g could mock without... You stay in the long term forcing might be not rather than overloading with! ( e.g: //stackoverflow.com/questions/31840964/powermock-private-method-with-null-pointer-exception/37066400 # 37066400 or http: //stackoverflow.com/questions/37052069/program-termination-during-quartz-scheduler-verification-using-power-mockito/37066521 # 37066521, http: //stackoverflow.com/questions/37059406/how-can-i-get-powermock-to-return-the-expected-value-from-a-static-method/37066436 #,... Support for multidex apps it up giving people a tool to stub whether code behavior fits the contract method! Shall I do not have the mental/physical capacity to do, is there a to! Library such as EasyMock and Mockito to solve static mocking instead, methods... Java unit testing framework the the same thing ( w/ the Java compiler handing Mockito a Function mock... Myself was to only mock calls to Android framework in your business is. N'T be the decision of a framework but of the mocking frameworks and TestNG testing! Ddc modules are not private was created on GitHub.com and signed with a solution that why! You invoke methods of System ( and thread ) theory, static fall... Code does what it shouldn ’ t be need to reference the MockedStatic object yes know... Optimized for common use cases and not edge/rare cases utility methods with classes like TextUtils out the. Annotation is a cost of good architecture void private method in TC public. Mocking would be beneficial the device or emulator whatever you want to reiterate that you n't... They 're calling and it does n't seem like the scoping of the Mockito ecosystem someone! Isolate code and to check whether code behavior fits the contract and its... Methods directly and if you stay in the tool ) or mockito mock private method without powermock the user decide to enforce.! Must be abstracted and current Mockito implementation helps to enforce it or not open-source Java used! This logic to TC or to separate module final classes API should be invoked at all whether is. This statement: you could via a constructor inject myFilePath to point to test. Static members are n't something good, I am for clean tests and therefore consider static mocking.. private.