Regarding generation of junit test cases of java classes - java

I am pure developer and spent most of time in writing the java classes , but the case of junit test cases , I become little bit lazy is there any plugin that can be installed in eclipse that will generate my junit test cases automatically..!! Please advise

MoreUnit is an awesome plugin that generates test classes and allows easy navigation between test and class under test. It can also generate test method stubs and mock boilerplate, but I don't think these are as useful.
As for the test code itself, the only way around writing it is to get someone else to write it (i.e. executable specifications).

The JUnit plugin stubs out the methods for you, which is all you should need. It's up to you to know what and how to test. There is this tool from Parasoft, but I have never used it, so can't say how it is.

Related

How does one test-run a non-main method? [Java, IntelliJ]

Is it possible to run a non-main method without running the main method (and thus the whole class)?
It seems like this would be useful to test your code while writing an incomplete program.
It’s called unit testing and for Java JUnit would be the most common tool for the job. It will allow you to run single classes or methods. To further help you out, a mocking tool (for example Mockito) will allow you to substitute classes with mocked implementations so you can construct a class without having to construct all the dependencies for real.
Since you mentioned your IDE, IntelliJ (and all IDE’s worth mentioning) have extensive support for JUnit. Usually there is also support for code coverage so you can even see how much of your code is being tested by your tests.

Mockito Junit testcoverage removal of unit test coverge

Hi recently we have done the unit testing for the entire project using mockito framework. My project is on Java spring rest project. But the coverage is below 35%. Need to improve the unit testing coverage.
1. Want to remove the unneccesay package from the code coverage, like test packages and beans class
2. Do we need to write the unit test case for the controller class and generated class from the tools.
I will be very grateful, if you can help me.
Test classes and packages are not counted in test coverage, if they were, how do you test the code that tests the code etc..
When you run coverage it should only run over src/main/Java etc.
Controller classes should be tested, when you call a method, is the correct delegated class and method called?
Generated classes, if from xml using jaxb etc do not need to be explicitly tested if they are just plain old Java objects with getter, setters and fields. It's likely they will be tested via another class that uses these objects and calls their methods. These classes will be generated/compiled before your tests run so will be available- make sure you aren't committing generated classes to your code repository.
You may want to consider testing the behaviour of third party libraries you depend on. This way you can instantly see if any updates to libraries may cause issues, but this should be from a high level.
You need to not start ignoring classes, but instead run a code coverage tool and see what's uncovered, and get those unit tests up to par. Test your failure cases, too!
The test packages should NOT be part of the 35%, so removing them is not going to help. None of the coverage tools I know of consider test packages.
As for generated classes - most likely not, but again, run a code coverage tool and you'll quickly see what needs to be covered.
If you use IntelliJ then coverage tools are built in:
https://www.jetbrains.com/help/idea/2016.2/code-coverage.html
Eclipse uses plugins, one is:
http://www.eclemma.org/
There are more if you google.
I prefer Sonar:
http://www.sonarqube.org/
But whatever tool you use, that's the way to go.

Why can classes being unit tested with JUnit not have a main?

My lecturer mentioned this before, but I don't really understand why this is the case. Would anyone be able to explain ?
We are writing a program to compute an array list of prime numbers, and we have to use JUnit to ensure all members of this arraylist are prime. Why can I not use a main in testing this class ?
Thank you very much :)
Ok these answers are for the most part too complex. I think your question is more fundamental. ANd its a very good one
The answer is when you become a java developer and start writing large amount of code that get updated/fixed over time then it helps to have a separate test plug-in that will automatically run tests on your code from outside the code to check if it’s still working in the way you would expect. This means you can fix/debug different aspect of the code for whatever reason and afterwards your boss walks over and asks does the code still do what the client wanted it to do since your fix? Without complication You can answer him without complex in-main error statements, which are mixed up with the normal program output (and slow down the code in non test conditions), but with a pretty green junit bar that says it all still works. You won’t see the value of this until you develop large projects and you have hundreds of tests to do. In addition junit has a number of other tricks up its sleeves...
Because JUnit is providing a main that calls the functions that you provide in your classes. You can still have your own main functions; they just won't get used when you run JUnit. You can use main functions to test your own classes individually, but using JUnit has some advantages as described in org.life.java's answer.
You can, it just wouldn't be recommended. If you write a unit test for testing it, then you can use the junit test runner to run the test and to produce a report indicating whether it passed or failed. If you don't do this then you'll need to code your own report mechanism.
Unit tests have the following structure normally:
Create test infrastructure
Execute test
Validate passed
Your situation has something similar and is thus a good candidate for using junit.
The unit testing API's available provide you with useful utilities that you would ordinarily have to code yourself.
Why don't you try both approaches and see for yourself.
In unit testing you are not testing anything as a whole. A unit test must test a UNIT normally a method. So you should write the method that computes your array, and use Junit to just test the method.
The main method is just an entrypoint and it "defines" the flow of the procedure. In unit testing we don't worry on flow. We just forcus on the unit. The program flow is verified using the System/Component test, not by the unit tests.
Because JUnit tests are run by a framework not as a standard console application.
The JUnit test runner finds the tests by reflection.
See the documentation here.
See: org.junit.runner.JUnitCore.main(String...), something like that is underlying.

I am new to automated testing in Java. Which tool should I prefer? JUnit or TestNG?

I have read some comparisons of JUnit and TestNG and it looks like TestNG has more configuration options. On the other hand JUnit is more supported by IDEs, building tools, has more plugins.
I have no experience in writing unit tests. Which tool should I prefer?
P.S.
I think my question is more like: Should I give TestNG a try, or just stick with JUnit as everybody else?
P.S.
We develop web applications, so I think the choice should also consider that we will use Selenium later for functional testing.
TestNG was written to overcome some perceived limitations of JUnit 3. Check out Cedric's blog post or other articles on the TestNG site to see his thinking.
Note that some of the limitations of JUnit 3 were by design and TestNG deliberately allows you to do things that the designers of JUnit expressly prevented.
The biggest advantage TestNG had over JUnit 3 was that it allowed you to use annotations to define your tests, rather than forcing you to extend the JUnit base classes. JUnit 4 can also use annotations in the same way now, narrowing the gap.
The biggest remaining difference between TestNG and JUnit is that TestNG allows your tests to be dependent on one another, and allows you to express those dependencies through the test annotations. JUnit instead forces all your tests to be independent of one another.
There are other differences too, of course – TestNG defaults to assertEquals(actual, expected, message) whereas JUnit is assertEquals(message, expected, actual) – but this is the biggest.
I'd say: pick one, and try it out. Write some tests. Both work fine with Selenium. Both work fine with ant. Both work fine with CruiseControl or Hudson. Learning to write good unit tests is far more important than learning a particular set of commands (they are pretty similar anyway).
TestNG has more power and fewer restrictions, IMO, but that gives you more opportunities to get things wrong too, of course.
If this is your first time, I'd recommend JUnit.
It was the first, most popular. It's well documented, has great tool support, and is the metaphor that is translated-- at least initially-- to all the different languages (see xUnit implementations). It should work fine for most any project, and it's a good tool to know. It will be a good baseline for you as a programmer.
There are other features of the "alternatives"-- that's why there are alternatives-- but often it's a matter of style more than anything else. TestNG may have a few different features, but JUnit has also evolved with features like annotations, alternative matchers, etc.
Yes, JUnit will work fine with Selenium when the time comes.
Combination of TestNg and Unitils is unbeatable..It would suffice all your requirements..
I always vote for 'as everybody else', because: this experience in most cases is more valuable, because there is a lot of info, and, for jUnit specifically, it is ported to many languages, so this experience will be 'cross-platform'.
Junit is most popular it supports plugins so better to use it
JUnit and TestNG are both quite similar and once you know one of them it is easy to pick up the other.
The main reason I use TestNG is for test groups and test dependencies. You can assign tests to different groups and then easily run all the tests in a group, or exclude certain tests from a group. For example, if I want to isolate a couple of tests, I can simply add them to a test group "fahd" and then run this group only. Test dependencies allow you to skip tests when a dependent test fails. You may think these features are not very important, but once you use them you'll wonder how you ever lived without them.
I work as JavaEE devel. We massively use JUnit for testing our business logic modules.It's very powerful, flexible and we use his html report in official release docs as a proof of quality.

JUnit vs TestNG [closed]

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At work we are currently still using JUnit 3 to run our tests. We have been considering switching over to JUnit 4 for new tests being written but I have been keeping an eye on TestNG for a while now. What experiences have you all had with either JUnit 4 or TestNG, and which seems to work better for very large numbers of tests? Having flexibility in writing tests is also important to us since our functional tests cover a wide aspect and need to be written in a variety of ways to get results.
Old tests will not be re-written as they do their job just fine. What I would like to see in new tests though is flexibility in the way the test can be written, natural assertions, grouping, and easily distributed test executions.
I've used both, but I have to agree with Justin Standard that you shouldn't really consider rewriting your existing tests to any new format. Regardless of the decision, it is pretty trivial to run both. TestNG strives to be much more configurable than JUnit, but in the end they both work equally well.
TestNG has a neat feature where you can mark tests as a particular group, and then easily run all tests of a specific group, or exclude tests of a particular group. Thus you can mark tests that run slowly as in the "slow" group and then ignore them when you want quick results. A suggestion from their documentation is to mark some subset as "checkin" tests which should be run whenever you check new files in. I never saw such a feature in JUnit, but then again, if you don't have it, you don't REALLY miss it.
For all its claims of high configuration, I did run into a corner case the a couple weeks ago where I couldn't do what I wanted to do... I wish I could remember what it is, but I wanted to bring it up so you know that it's not perfect.
The biggest advantage TestNG has is annotations... which JUnit added in version 4 anyways.
First I would say, don't rewrite all your tests just to suit the latest fad. Junit3 works perfectly well, and the introduction of annotations in 4 doesn't buy you very much (in my opinion). It is much more important that you guys write tests, and it sounds like you do.
Use whatever seems most natural and helps you get your work done.
I can't comment on TestNG b/c I haven't used it. But I would recommend unitils, a great wrapper for JUnit/TestNG/DBUnit/EasyMock, regardless of which route you take. (It supports all the flavors mentioned above)
TestNG's biggest draw cards for me include its support test groups, and more importantly - test group dependencies (marking a test as being dependent of a group causes the tests to simply skip running when the dependent group fails).
TestNG's other big draw cards for me include test parameters, data providers, annotation transformers, and more than anything - the vibrant and responsive user community.
Whilst on the surface one might not think all of TestNGs features above might not be needed, once you start to understand the flexibility bring to your tests, you'll wonder how you coped with JUnit.
(disclaimer - I've not used JUnit 4.x at all, so am unable to really comment on advances or new features there).
About a year ago, we had the same problem. I spent sometime considering which move was better, and eventually we realized that TestNG has no 'killer features'. It's nice, and has some features JUnit 4 doesn't have, but we don't need them.
We didn't want people to feel uncomfortable writing tests while getting to know TestNG because we wanted them to keep writing a lot of tests.
Also, JUnit is pretty much the de-facto standard in the Java world. There's no decent tool that doesn't support it from the box, you can find a lot of help on the web and they added a lot of new features in the past year which shows it's alive.
We decided to stick with JUnit and never looked back.
Cheers to all the above. Some other things I've personally found I like more in TestNG are:
The #BeforeClass for TestNG takes place after class creation, so you aren't constrained by only being able to call static methods of your class in it.
Parallel and parameterized tests, maybe I just don't have enough of a life... but I just get a kick writing one set of Selenium tests, accepting a driver name as a parameter. Then defining 3 parallel test groups, 1 each for the IE, FF and Chrome drivers, and watching the race! I originally did 4, but way too many of the pages I've worked on break the HtmlUnit driver for one reason or another.
Yeah, probably need to find that life. ;)
I wanted to share the one I encountered today. I found built-in Parameterized runner is quite crude in Junit4 as compare to TestNG (I know each framework has its strengths but still). The Junit4 annotation #parameters is restricted to one set of parameters. I encountered this problem while testing the valid and invalid behavior for functionality in same test class. So the first public, static annotated method that it finds will be used, but it may find them in any order. This causes us to write different classes unnecessarily. However TestNG provides clean way to provide different kind of data providers for each and every method. So we can test the same unit of code with valid and invalid way in same test class putting the valid/invalid data separately. I will go with TestNG.
Also one more advantage of TestNG is supporting of parallel testing. In our era of multicores it's important, i think.
I also used both frameworks. But i using hamcrest for assertations. Hamcrest allows you easily write your own assert method. So instead of
assertEquals(operation.getStatus(), Operation.Status.Active);
You can write
assertThat(operation, isActive());
That gives you opportunity to use higher level of abstraction in your tests. And this makes your tests more robust.
JUnit 4 Vs TestNG – Comparison by mkyong.com ( updated on 2013).
Conclusion: I suggest to use TestNG as core unit test framework for Java project, because TestNG is more advance in parameterize testing, dependency testing and suite testing (Grouping concept).
TestNG is meant for functional, high-level testing and complex integration test. Its flexibility is especially useful with large test suites.
In addition, TestNG also cover the entire core JUnit4 functionality. It’s just no reason for me to use JUnit anymore.
In simple terms, TestNG = JUnit + lot more. So, Why debate ? go and
grab TestNG :-)
You can find more detailed comparison here.
Why we use TestNG instead of JUnit?
The declaration of #BeforeClass and #AfterClass method has to be static in JUnit whereas, there is more flexibility in TestNG in the method declaration, it does not have these constraints.
In TestNG, we can parametrize tests using 2 ways. #Parameter or #DataProvider annotation.
i) #Parameter for simple cases, where key value mapping is required.(data is provided through xml file)
ii) #DataProvider for complex cases. Using 2 dimensional array, It can provide data.
In TestNG, since #DataProvider method need not be static, we can use multiple data provider methods in the same test class.
Dependency Testing: In TestNG, if the initial test fails, then all subsequent dependent tests will be skipped, not marked as failed. But JUnit marked it failed.
Grouping: Single tests can belong to multiple groups and then run in different contexts (like slow or fast tests). A similar feature exists in JUnit Categories but lacks the #BeforeGroups / #AfterGroups TestNG annotations that allow initializing the test / tearing it down.
Parallelism: If you’d like to run the same test in parallel on multiple threads, TestNG has you covered with a simple to use annotation while JUnit doesn’t offer a simple way to do so out of the box.
TestNG #DataProvider can also support XML for feeding in data, CSVs, or even plain text files.
TestNG allows you to declare dependencies between tests, and skip them if the dependency test didn’t pass.
#Test(dependsOnMethods = { "dependOnSomething" })
This functionality doesn’t exist in JUnit
Reporting:
TestNG reports are generated by default to a test-output folder that includes HTML reports with all of the test data, passed/failed/skipped, how long did they run, which input was used and the complete test logs. In addition, it also exports everything to an XML file which can be used to construct your own report template.
On the JUnit front, all of this data is also available via XML, but there’s no out of the box report and you need to rely on plugins.
Resource Link:
A Quick JUnit vs TestNG Comparison
JUnit vs. TestNG: Which Testing Framework Should You Choose?
A good difference is given in this tutorial side by side: TestNG Vs JUnit: What's the Difference?
A couple of additions to Mike Stone's reply:
1) The most frequent thing I use TestNG's groups for is when I want to run a single test method in a test suite. I simply add this test to the group "phil" and then run this group. When I was using JUnit 3, I would comment out the entries for all methods but the one I wanted to run in the "suite" method, but then would commonly forget to uncomment them before checkin. With the groups, I no longer have this problem.
2) Depending on the complexity of the tests, migrating tests from JUnit3 to TestNG can be done somewhat automatically with sed and creating a base class to replace TestCase that static imports all of the TestNG assert methods.
I have info on my migration from JUnit to TestNG here and here.
My opinion about what makes TestNG truly far more powerful:
1. JUnit still requires the before/after class methods to be static, which limits
what you can do prior to the running of tests, TestNG never has this issue.
2. TestNG #Configuration methods can all take an optional argument to their
annotated methods in the form of a ITestResult, XmlTest, Method, or
ITestContext. This allows you to pass things around that JUnit wouldn't
provide you. JUnit only does this in listeners and it is limited in use.
3. TestNG comes with some pre-made report generation classes that you can copy
and edit and make into your own beautiful test output with very little
effort. Just copy the report class into your project and add a listener
to run it. Also, ReportNG is available.
4. TestNG has a handful of nice listeners that you can hook onto so you can do
additional AOP style magic at certain phases during testing.
Your question seems two folded to me. On one had you would like to compare two test frameworks, on the other hand you would like to implement tests easily, have natural assertions, etc...
Ok, firstly JUnit has been playing catchup with TestNG in terms of functionality, they have bridged the gap some what with v4, but not well enough in my opinion. Things like annotations and dataproviders are still much better in TestNG. Also they are more flexible in terms of test execution, since TestNG has test dependency, grouping and ordering.
JUnit still requires certain before/after methods to be static, which limits what you can do prior to the running of tests, TestNG never has this issue.
TBH, mostly the differences between the two frameworks don't mean much, unless your focusing on integration/automation testing. JUnit from my experience is built from the ground up for unit testing and is now being pushed towards higher levels of testing, which IMO makes it the wrong tool for the job. TestNG does well at unit testing and due to its robust dataproviding and great test execution abilities, works even better at integration/automation test level.
Now for what I believe is a separate issue, how to write well structured, readable and maintainable tests. Most of this I am sure you know, but things like Factory Pattern, Command Pattern and PageObjects (if your testing websites) are vital, it is very important to have a layer of abstraction between what your testing (SUT) and what the actual test is (assertions of business logic). In order to have much nicer assertions, you can use Hamcrest. Make use of javas inheritance/interfaces to reduce repetition and enforce commonality.
Almost forgot, also use the Test Data Builder Pattern, this coupled with TestNG's dataprovider annotation is very useful.

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