I have existing code which uses mockito to mock the public interface in class.
I am adding some static methods in same class so planing to use powermock.
Does powermock allow to keep the existing functionality of mockito ?
From PowerMock's Getting Started Page:
PowerMock consists of two extension API's. One for EasyMock and one for Mockito. To use PowerMock you need to depend on one of these API's as well as a test framework. Currently PowerMock supports JUnit and TestNG.
If you are using PowerMock and its Mockito extension API, you will also depend on Mockito—and these two tools interact just fine. Use pure Mockito wherever possible, and use PowerMock to handle legacy code cases and other places where you need to mock final classes, final/static methods, and so forth.
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I have for long worked on EasyMocking in JUnits. I am pretty much comfortable with this but now I want to know how EasyMocks are different from Jmockits. I tried going through their documentation and I found out that the syntax is a bit different. But yet I could not figure out if there is any difference in their performances.
Can anyone help me figure out what are the points that make either of them better than the other? Is there any special element in JMockit that is not found in the other?
Thanks in advance...
There are many differences between JMockit and EasyMock/jMock/Mockito/PowerMock.
These are the major ones:
Support for integration testing: JMockit supports an out-of-container integration testing approach, similar to what the Spring Test module provides, but also supporting Java EE. The other mocking libraries only support isolated unit testing with mock objects.
A "faking" API (see also in xUnit Patterns), in addition to the mocking API. Each one of the other mocking libraries only have a mocking API.
Full support for "mocking", in addition to "mock objects". Other mocking libraries work with mock objects which they create and which need to be passed in somehow to the code under test. With EasyMock/jMock/Mockito, static methods, constructors, and "new-ed" objects cannot be mocked at all. PowerMock supports full mocking as well, but still focused on mock objects (specifically, new-ed objects must be "replaced" with mock objects through whenNew recording, while with JMockit a test can simply declare a #Mocked field).
Support for mocking/faking of final classes and methods. Only PowerMock also provides this support. Mockito recently added an "inline mock maker" which adds support for finals, but it's not active by default and may not be as reliable.
Support for mocking/faking of unspecificied subclasses and interface implementations (where the test only declares a base type to be mocked/faked).
In the mocking API, expectations on methods with multiple parameters can be recorded/verified with argument matchers (such as anyString, etc.) only for some parameters, while other mocking APIs require such matchers for every single parameter.
Also in the mocking API, expectations can be explicitly verified after the tested code was exercised, just like in Mockito. EasyMock/jMock do not support this verification model.
As for performance, mocking a type with JMockit (done through class redefinition) probably has a higher runtime overhead when compared to creating a mock object with EasyMock/jMock/Mockito (done through subclass definition), and lower when compared with PowerMock (done through class definition on a custom classloader). However, you should only notice the difference in performance if there is a lot of mocking being done, which most likely indicates overuse of mocking.
You can find a blog post about the differences between them (and also mockito!) here: http://www.baeldung.com/mockito-vs-easymock-vs-jmockit
While they all have different syntax and different ways of working, you should be able to achieve whatever you need in regards to mocking with either framework.
I want to know what Mockito is.
Is it supporting JUnit or is it an environment for writing JUnit test cases?
Can someone please explain to me the differences between JUnit and Mockito?
JUnit is a framework that helps with writing and running your unit tests.
Mockito (or any other mocking tool) is a framework that you specifically use to efficiently write certain kind of tests. At its core, any mocking framework allows you to omit instantiating "real" objects of production classes, instead the mocking framework creates a stub for you. Doing so gives you full control over that mocked object and enables you to verify the interactions taking place, for example.
Having said that, one core aspect in unit testing is the fact that you want to isolate your "class under test" from anything else in the world. In order to do that, you very often have to create "test doubles" that you provide to an object of your "class under test". You could create all those "test doubles" manually; or you use a mocking framework that generates object of a certain class for you using reflection techniques. Interestingly enough, some people advocate to never use mocking frameworks, but honestly I can't imagine doing that.
In other words, you can definitely use JUnit without using a mocking framework. Same is true for the reverse direction, but in reality, there are not many good reasons why you would want to use Mockito for anything else but unit testing.
JUnit is the Java library used to write tests (offers support for running tests and different extra helpers - like setup and teardown methods, test sets etc.).
Mockito is a library that enables writing tests using the mocking approach.
See here a nice article on the mocking vs non mocking tests: http://martinfowler.com/articles/mocksArentStubs.html
Layman's Explanation with Example
JUnit is used to test APIs in source code. To test APIs in JUnit, sometimes we may require data classes. To create those, we can use mockito.
Mock refers to creating duplicate or dummy objects.
We might be using many data classes in the project. For example, think of a Student object. It might have some 10 parameters like id, age, marks, gender etc. But you have one API to return a list of students whose age is greater than 10. So, to test this API we need to create student objects with all 10 parameters right. It is difficult. So, we can mock objects only with the required parameters. In our scenario, we will mock student objects with only age as a parameter.
Student student1=mock(Student.class);
when(student1.getAge()).thenReturn(20);
Student student2=mock(Student.class);
when(student2.getAge()).thenReturn(8);
So,above 2 objects can be added to a list and can be passed to API to test if API returns students who has age greater than 10.
I'm having a simple test design problem, which I would like to solve once and for all.
I'm pretty used to regular Java design pattern where there is some Manager interface (or facade) and a set of DAO interfaces. Concrete implementation of ManagerImpl is using concrete implementations of DaoImpl.
Right now I'm at the point of implementation, where I don't have a database connected to my project yet, so I guess this is a perfect time to write proper unit tests without DB :-)
I was able to mock some methods of my manager by using mockito, but since the Test Under Method (or so called System Under Test) is using DAO internally, I would have to mock the DAO as well. Unfortunately I cannot do that without setting concrete DAO implementation in my manager, like myManager.setMyDao(mockedDao), but now I would have to pull out this setMyDao method into interface, which of course breaks encapsulation and makes my clean and perfect interfaces look like garbage.
So the question is: How to mock DAO in tests while preserving clean Manager-Dao architecture?
You should unit test concrete implementations, i.e. ManagerImplTest, which will explicitly create ManagerImpl and therefore you have all setMyDao methods available for mocks. Your test will not know about Manager interface.
BTW, it is not always necessary to create interfaces for everything. In most cases only single implementation of managers and daos will exist. If there is no any other strong reason (e.g. Spring AOP proxies or dependency separations), I guess it's better don't create interfaces for everything in sake of simplicity.
You can get rid of set methods altogether and inject factory. This way no extra method is exposed (in fact, no extra method even exists) and problem disappears. Then in test you configure factory mock to return DAO mocks and from that point on it's plain and simple.
I'm trying to set up and use Mockito into a GWT project, and I'm having trouble using it on the client side (in javascript). I tried to add a module and include Mockito, but it seems not to work (lots of errors). I also tried to do a full checkout from svn and integrate GWT in it that way, the same errors. How should this be done? Thanks.
GWT code tested with mocking framework (like Mockito) runs in JVM and no compiling to JavaScript, obviously. Thus, any JavaScript-related implementations should be mocked or stubbed using mock objects.
One architecture that receives wide adoption in GWT and that simplifies testing is MVP (variation of MVC). MVP places majority of meaningful functionality inside classes called presenters. Presenters do not rely upon GWT implementation classes but instead depend on GWT interfaces (mostly). Then Mockito is applied to mock/stub those interfaces to unit test presenter classes.
This blog is full of examples on both MVP in GWT and testing with mock objects (EasyMock).
And now there is https://github.com/google/gwtmockito which is probably what you need.
Without more specifics I can only say that mocking frameworks make heavy use of dynamic proxies and run-time code generation which will not be compiled by GWT.
Your best bet is using these mocks in plain JUnit tests.
I am trying to set up some unit tests for an existing c++ project.
Here's the setup:
I have chosen Google Mock, which includes Google Test. I have added another project (called Tests) to the Visual Studio Solution. The units to test are in another project called Main. The plan is to add each cpp file that I want to test to the Tests project. The Tests project has access to all header files from Main.
I have added one cpp file to the Tests project, and it compiles, but comes up with linker errors. Most are because of a class derived from COleDateTime, called CTimeValue. The unit under test has methods with pass-by-value CTimeValue parameters and also declares some CTimeValue attributes.
I want to test the UUT in isolation, and use mocks and fakes for all dependencies. I don't see how to do it with CTimeValue. It is used as a value, contains no virtual methods, but is still quite complex and would deserve a seperate unit test.
CTimeValue is only one of many classes that is like this in the project. How can I isolate the testing of classes that use these user-defined types?
Cheers, Felix
Sometimes one can not simply mock things. In that case what you can do is have a comprehensive test for the class in question (CTimeValue) and make sure you run the tests for that class as a subsuite in your other test.
Using a mock object you only need to add the method signatures that your UUT uses so maybe you can create a mock using google mock. Of course you will need a separate test suite for the CTimeValue class, and if you have that then it is probably better to link in the actual object. You need to decide if it is worth the effort to create an interface class to create the mock from.
Mocks are most suitable for working with objects that provide services for each other, the expectations on the mocks describe their relationships. There's not much point in mocking value objects.