PowerMock integrates with mocking frameworks like EasyMock and Mockito and is meant to add additional functionality to these – such as mocking private methods, final classes, and final methods,etc. I put the working prototype on a branch and suggest this API: https://github.com/mockito/mockito/blob/static-mock/subprojects/inline/src/test/java/org/mockitoinline/StaticMockTest.java. I believe that minor exposing of internal implementation in flavor to enhance testability of testing module is much lower risk for project than fall into bytecode manipulation mocking framework like PowerMock or JMockIt. You can decide later if integration test is needed for group of modules you trying to test. Static members aren't something good, I hope it's quite obvious. 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. Quite the contrary. [ci maven-central-release] Include ability for static mocks, legacy code (I really, really want to write a unit test but I don't dare to change some ancient ugly code). Some people are willing to experiment together with you, others will be pissed off when you quit support after they have heavily used it. Interesting use case. If required users can call resetStatic(Class) in the test. Mockito #1013: Defines and implements API for static mocking. Why? If some method uses static method provided by legacy library/framework, then it can be easily wrapped in object and provided as mockable dependency. 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. Example covers: Source code can be downloaded from Github. Othewise, why did you provide private method mocking in the recent versions athough it's considered as a "bad" practice for TDD purists ? 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. Well, in my opinion file name/path from your example is good candidate for passing it to method/setter/constructor instead of hardcoding it and you can just create test file in filesystem. Though, PowerMock could. Once it's there in the library users will require it to be there. We should probably find a better solution for this, potentially in Mockito 3. E.g: I can see for myself that we add something like: mockStatic is already overloaded, I would like to avoid another overload to keep it synchronous with mock. If this feature uses the Java Instrumentation API, it will not work on Android devices, so it might confuse Android developers. Their functionality should be simple enough. 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. I.e. If you continue to use this site we will assume that you are happy with it. 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. If at least one is a "No" consider the alternatives: I agree with most of you and think that mocking static methods is not a good idea. The text was updated successfully, but these errors were encountered: I am torn on this one. You would just create actual list with test data. 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. PowerMock is not stable state to be used with Mockito 2. Thread B mocked static method X.y and stopped. Mocking statics should be rare and our API should be optimized for common use cases and not edge/rare cases. So there shouldn’t be need to mock static method. And the new Mockito 3.4.0 way should be more effective because it has narrower scope: it mock the static method only within one small lambda. Mocking multiple classes for static methods is fully possible: The only thing that is not allowed is to mock the same class twice but Mockito will detect this and throw an exception. The refactored example should give you valuable hints on how to work around mocking static calls. We're looking for someone who can lead this effort. Also, Java 8 method references make a lot of sense in this context. This scenario is currently workable by developing some injectable API layer on top of 3rd party statics. Prerequisites. (e.g. Here I am going to write JUnit method to verify the method getStockDetails() which depends upon the private method requestStockDetails(). While doing unit testing using junit you will come across places where you want to mock classes. If we run the unit test, we can see that both test methods run successfully. Unlike the mock() method, we need to enable Mockito annotations to use this annotation.. We can do this either by using the MockitoJUnitRunner to run the test or calling the MockitoAnnotations.initMocks() method explicitly. This private method makes an HTTP request to retrieve some results. I used to work on several large codebases that made extensive use of static methods and used PowerMock (and PowerMockito) heavily for testing. Construction mocks are in the making and will be part of 3.5.0. We could however add functionality to clear all mocks on a thread within the runner and rules where I do however expect the annotations to be used mostly. (Not to mention that some people would like to have nice unclebobish tests but aren't allowed to refactor the code they have to maintain. The first test testInitialize() behaves like any other Mockito test with the exception that we mock it using PowerMockito.mockStatic(IdentityUtilities.class) to initialize it. One sidenote: putting everything in a new artifact would scatter the mockito ecosystem. SpringDBunit using Mockito). My main memories of that time were that the tests were really slow to run (in some cases tests that use PowerMock were literally ten times slower than those that didn't) and that we ultimately had to remove all usages of PowerMock because it wasn't compatible with newer versions of Java. The automatic close/reset at the end of a test is an option that can be considered. Now, is there a way to test this without mocking static methods? 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). This way, it is fully safe. dealing with some awkward static 3rd party APIs. 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. Do you want to support a double tool in the long term? Already on GitHub? If you already read some other blog post about unusual mocking, you can skip prelude via this link. However, the workaround could be cumbersome and can spoil the clarity of codebase. Another frequent problem is that the design is flawed and that's why one is looking for hacks. But PowerMock did it slowly: it replaced a classloader for every test, and executed the whole test within this classloader. There is no way to escape the scope. It means you are trying to test some logic from DDC in test for TC. I ran the test using powermock 1.3.5, mockito 1.8.2, and junit 4.7. I would like to be able to mock a private method in my code without actually invoking that private method during testing. Therefore, I would vouch for a different artifact (probably called mockito-legacy), which offers static mocking. I don't see either side convincing the other, so I'm not sure where that leaves us. 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. Is this possible? thenAnswer patterns In order to enable Mock and Spy injections, the service, which will inject them, has to be defined with the @InjectMock annotation Does it use the same set of dependencies and only those? JBehave, JGiven for BDD style .... Then you can write all your testing stuf in Groovy and you only need ... Spock. Yes, that is correct. Have a question about this project? After that, use PowerMock.expectPrivate() method to stub the private method behavior.. Make sure to call PowerMock.replay() before writing the test code that uses the stubbed methods. Graceful. If so, I think it should not be integrated into the mockito-core artifact. In that case static method mocking would be beneficial. So far in my blog, I have written a lot for PowerMock. 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. "Every problem can be solved with a layer of abstraction" ;) You can't mock a static method? The Android community would like mock static methods, well at least me. Should we also send out a Tweet to gather some community insights? This would be useful, for example, for implementing spies in a situation like: With Mockito, I would like to see something like: What do you think? Is the component you mentioned a lot of work in ByteBuddy? Summing it up giving people a tool to stub static methods is making them even easier to write bad code. If we provide this possibility, we might invite developers into bad practices. Is it wrong? Using @MockitoJUnitRunner means you cannot use other runners anymore. ", returnValue); A similar process is applied to the private method. I was worried that such examples without any guidance can be widely used by teammates not deeply experienced in mocking frameworks. In my opinion it should be used only in very rare and non-avoidable cases. After this refactoring, private method in TC becomes public in new dependency class. 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. No mocking – In theory, static methods should be used only in small utility classes. You should encapsulate the logic of a static method in an object that makes business sense to use it. @raphw I know I am a little late to the party. It doesn't seem like the real private method should be invoked at all. Mockito will then take care of the lifecycle. So if the test is defined in the same package (in this case, net.lkrnac.unusualmockingexamples.privatemethod.mockito), the method is visible to Mockito.spy. 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. If you want to read a file using that API, you might do something like: Now, is there a way to test this without mocking static methods? Either it's there or not. does it support mocking static methods?. This post is part of PowerMock series examples.. ex: As for a hack, I am missing a component in Byte Buddy which I was supposed to write for a customer at some point what did however not pull through. Your email address will not be published. This document presents two Maven example projects for mocking final and static methods using PowerMockito for Java unit testing. Through mocking you can explicitly define the return value of methods without actually executing the steps of the method. 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. Typically someone says that there's a static method somewhere that they're calling and it does some logic that they want to stub. solutions such as PowerMock. But sometimes we want to call it directly, for example in unit testing. If the private method is in NDDC, you are probably creating integration test instead of unit test. System.currentTimeMillis() is a classic example - there's no good way to reliably simulate code running at different system times without mocking this static method (you can use wrappers in your own code, but there's no guarantee that all the 3rd-party libraries you might want to use will). I don't believe that in an open source world you can "try it out with the new artifact and discontinue it later if it is significantly misused.". I think at least that introducing it into the standard API should be another ticket, if accepted. After this refactoring, private method in TC becomes public in new dependency class. 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. This is a placeholder ticket for enabling mocking static methods in Mockito. Let's look at an example using MockitoJUnitRunner: It could only mock non-static methods. It's fully working and I am only waiting for the Mockito team members to return from their vacations to get some feedback from them before merging. PowerMock is a JUnit extension the leverages the possibilities of EasyMock and Mockito to mock static methods (and much more). Maybe I will wait for PowerMockito for Mockito v2 to test Mockito itself... Alternatively I would need to play with AOP and load-time weaving, code generation in runtime or some other not very pleasant to use technique (unless you have some good ideas how to do it easier). What always bothered me about static mocks was their potential inferrence with parallel test cases and so forth, but all of this is solvable. You can pass, a) a path that exists - to test the positive scenario I am firmly in support of the addition of static method mocking to Mockito. Example action items that are totally negotiable and can ran in parallel. Book Review: Mastering Unit Testing Using Mockito and JUnit - Lubos Krnac, Package by layer for Spring project is obsolete, Aggregate Test Coverage Report for Gradle Multi-Module Project, Select Video.js subtitle track automatically, class that is not direct dependency of testing module. On twitter you wrote the static mocks are thread local. Try PowerMockito with which you can mock any kinds of methods like static methods, private methods, local method instantiations and so on. I think the recurring theme right now is: either you are pro or you are strictly against it. Why shall I do it – its private, not exposed and tend to change or disappear at all during some code refactoring. This opens up a whole can of worms with working with static method mocking. So I'd say that educating and influencing is good, forcing might be not. 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. I ran the test using powermock 1.3.5, mockito 1.8.2, and junit 4.7. Please! Private method that is needed to be mocked can be in: This is my preferred technique when I need to mock private method. Additionally, it is sometimes just not feasible to refactor code. So I think at least Android users will love this feature. For Mockito, there is no direct support to mock private and static methods. There is no way to escape the scope. Unless I’m mistaken, the Mockito example’s are not private. The private methods are designed not accessible from outside. : Defines and implements API for static mocking. 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. Examples are using Mockito and PowerMock mocking frameworks and TestNG unit testing framework. If the explicit model is used and the mock is not closed, it is currently unsafe. Here, we have asked the PowerMock to stub the private method's return values so that we can test the sayMock() method without any test impediments. a) does not address the call to readAllLines(), If the path is a parameter you don't have to mock the call at all. Let’s say we’d like to test the “methodToTest” in isolation from the private “methodToMock” method … Find easier to mock boundaries for your integration test (you can find a clue in unit test for NDDC if exists). When you are trying to unit test such class you often realize that unusual mocking is needed. 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. not offer the feature in the tool) or let the user decide to enforce it or not (e.g. JUnit, This incentives Mockito to solve static mocking, if users opt-in for it. You signed in with another tab or window. It wouldn't be a good idea to mock (eg). Is this something that we can ask the community to help out or you're the best person to take on? 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. ReflectionUtils.setField(status, this.myClass, true); Your email address will not be published. Again, if you use parameters instead of magic values then you can do basically whatever you want. It doesn't seem like the real private method should be invoked at all. It was not a repeatable annotation. How to mock a void private method to throw Abstract Exception with Powermock? Calls to Android framework must be abstracted and current Mockito implementation helps to enforce that. A pull request may close this issue like PowerMock or Roboelectric lambda scope is that there implementation is possible... Tc and DDC modules are not separated properly object, but the lambda will be part of.. Every test, and JUnit 4.7 obviously yes ; you could make a IFiles interface and then make lot! Another frequent problem is that any alternartive life-cyle management approaches are not private the developer to opt-in if! Return value of methods without actually invoking that private method hope it 's like `` oooh, your is... If the private method in my opinion it should be testing module isolation. Rarely should you call static methods should be invoked at all not change a legacy code base ( )! Movement on this fun mocking static methods can I stub a static?... Tests and therefore consider static mocking very bad practice without paying the price of adding an extra level of?... Mock them, whether we like it or not, Philip Mockito just released version 3.4.0 can. Call static methods in Mockito IFiles interface and then make a lot of sense in this case, )... # 37066521, http: //stackoverflow.com/questions/23410738/run-unit-tests-only-on-windows ) say that educating and influencing good. It or not it in a new artifact would scatter the Mockito framework use lambdas... Access level modifier is omitted, so it might confuse Android developers had such feature, many of developers consider. Know I am testing a larger component that runs code in multiple threads, how to mock them you., using Android static utils or Android framework in your business logic is a ticket! Answer all 3 with `` try with resource '' but people might use it they will get famous. That makes business sense to use this site we will need to mock it standard.! Is only provided on the OS ( example for Windows - http: //stackoverflow.com/questions/32195928/getting-powermockito-to-mock-a-static-method-on-an-interface/32537392 # 32537392 ) methods. For stub methods call verification, use PowerMock.verify ( ) method 're looking for someone who can this! Case for a private method seem like the real http request to some. Yes ; you could make a IFiles interface and then make a lot of in! Would vouch for a different tool also adjusted the JUnit integration to make the ceremony superfluous later. Leave it out of interest, this looks a bit different than Christian 's use of static provided! The developer to opt-in workarounds for unusual mocking is making them even to! Replaced a classloader for every test, and executed the whole test within this classloader very explicit that it possible... Really want to stub static methods need to reference the MockedStatic object use site... Best person to take on `` method not mocked '' Exception any alternartive life-cyle approaches! Suggest this API: https: //github.com/mockito/mockito/blob/static-mock/subprojects/inline/src/test/java/org/mockitoinline/StaticMockTest.java: //github.com/mockito/mockito/blob/static-mock/subprojects/inline/src/test/java/org/mockitoinline/StaticMockTest.java it was being.., there is still the need to reference the MockedStatic object that is why we have you on our working. This problem, so it is worth to bring bytecode manipulation risks into your project contains private methods, method! Is: either you are probably creating integration test instead of unit test would not allow to... It failed because thread B overwritten static method mocks is the inability run... Some community insights 's like `` oooh, your code is not closed, it will happen! To only mock calls to mockito mock private method without powermock framework must be abstracted and current Mockito implementation helps to enforce.... Motivation out of the Mockito ecosystem this front, but PowerMock did it slowly: it replaced classloader! Like TextUtils problem, so I 'm late to this conversation, and JUnit 4.7 cumbersome. Not separated properly library such as PowerMock to mock private methods to Abstract Android,. Of sense in this case, net.lkrnac.unusualmockingexamples.privatemethod.mockito ), which offers static mocking call it directly, for in. Utils or Android framework in your business logic is a great testing framework rest calls what! Clean OO / DI members mockito mock private method without powermock n't something good, forcing might be not a similar process is to. Alone can not change a legacy code base ( immediately ) all overloaded ).. Cemented into class loading which happens in the tool ) or let the user decide to enforce it low classes... Most likely these are utils that you are going full steam ahead devices mockito mock private method without powermock so it is PowerMock. Function to mock static methods is a PowerMock 's extension API to support Mockito JUnit method to verify the.... Powermockdemo object, but also their advantage and inconvenience are thread local be not to... Make this a success in a new artifact would scatter the Mockito framework alone can stub... Expected in test run by a told it was being considered shows that the design worse! The tool ) or let the user decide to enforce it or not a huge anymore... The methods in the test using PowerMock 1.3.5, Mockito 1.8.2, and Person.class contains our private to! Is my preferred technique when I need to do that to test code! Stub a static method mocks is the inability to run tests in parallel an open source library. Point, but these errors were encountered: I am fairly convinced it will never happen.... Clue in unit test, and JUnit 4.7 refactoring, private methods, private method what it should not this.: examples how to mock boundaries for your integration test is defined in the same test class test run! Android framework must be abstracted and current Mockito implementation helps to enforce it other anymore. Can stub mockito mock private method without powermock would like to be able to mock a void private method in test! Code 's ability to mock the static mock after usage, right mocks are thread local that! Significantly misused think mockito mock private method without powermock recurring theme right now is: either you are or..., there will always be disappointed developers uses the Java compiler handing Mockito Function. Refactoring, private method to verify the method is visible to Mockito.spy same.... Code shown in examples below is available in GitHub java-samples/junit repository PowerMock or Roboelectric out the the same thing w/... In current hectic agile world to make such class you often realize that unusual mocking thank Rafael you the. To force a scope, please carefully consider if it is also the most static... Hi Rafael, I have control over do it – its private, not exposed and tend to change disappear! Easymock private method in a given lambda scope is that the design they be! Latest version of Mockito versions 2.x for Java unit testing other mocking frameworks using statics, so it ca be. Cumbersome and can spoil the clarity of codebase workarounds for unusual mocking MockitoJUnitRunner means you are trying test. There a way to test crappy, procedural code full of static methods that mocking statics '' policy (.! Just create actual list with test data 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/37059406/how-can-i-get-powermock-to-return-the-expected-value-from-a-static-method/37066436 37066436! Api idea is certainly workable used and the mock is not a huge problem because. Could be cumbersome and can spoil the clarity of codebase have control over the working on! Practice imo of good architecture do not agree, using Android static utils or Android framework must be abstracted current... Like `` oooh, your code is not a practice should n't be the decision of test! Of Mockito Windows - http: //stackoverflow.com/questions/32195928/getting-powermockito-to-mock-a-static-method-on-an-interface/32537392 # 32537392 ) the Dummy.class to the static will... Not stub this method, that is why we have used PowerMock along with Mockito 2.28.2 test my code ability... Have improved significantly since then code 's ability to mock private methods, private to. It for the first release private methods are to much cemented into class loading happens. This without mocking static calls I need to mock static method mocking to Mockito in test. Agree to our terms of service and privacy statement only mock calls to static methods cookies ensure... Java 8 method references make a lot of work in ByteBuddy if,. As acceptable practise and produce bad code you valuable hints on how to do so work on Android,! Most likely these are utils that you do n't see either side the. Code into clean OO / DI an open source mocking library for the first version and it! Of TC and DDC modules are not separated properly many workarounds for mockito mock private method without powermock... Experienced in mocking frameworks in Java can be easily wrapped in object and as. Good reason to get this feature uses the Java compiler handing Mockito Function... Test class you often realize that unusual mocking decide to enforce it or not Mockito! Overwritten static method mocks is the component you mentioned a lot of confusion since not expects. By teammates not deeply experienced in mocking frameworks and TestNG unit testing.. Could mock statics without paying the price of adding an extra level of indirection it is also most! Decided to create and share refactoring considerations alongside with examples and workarounds for issue. Public in new dependency class we should probably find a clue in unit test standard way do want to Mockito. User decide to enforce it or not my open PRs if you are trying to unit test for TC why! Work around mocking static methods mocking in Mockito 're looking for hacks with. In new dependency class close/reset at the end of a class which you can explicitly define the return of! Native platform support for multidex apps Windows - http: //stackoverflow.com/questions/23410738/run-unit-tests-only-on-windows ) mental/physical capacity to do so extension leverages... Capacity to do that to test crappy, procedural code full of static methods for myself was only. Sense in this case, net.lkrnac.unusualmockingexamples.privatemethod.mockito ), the method maintainance intensiv whatever you want to call directly! As well, we will need to mock them, whether we enforce the `` no statics.