Running JUnit Tests in Parallel in IntelliJ IDEA - java

I have a large suite of tests that takes about half an hour to run and would love to be able to the test classes in parallel.
Is there a way to do that with IntelliJ IDEA 9?

IDEA will understand parallel JUnit tests only since version 10.
There is a tracker issue which you can vote for and watch for progress:
http://youtrack.jetbrains.net/issue/IDEA-47103
We plan to add it in IDEA 10, but the priority would depend on the number of votes.

Answering late for posterity.
You can make JUnit tests run in parallel (or serial) to any level of granularity in IntelliJ by changing the Fork mode in the test's run configuration.
Be careful not to confuse this with the Allow parallel run option, which lets you start the test execution multiple times within your IDE.

UPDATE in 2022: This plugin lets you run and debug tests in parallel in IntelliJ IDEA with JUnit4, JUnit5 and TestNG: https://plugins.jetbrains.com/plugin/16229-unit-test-parallel-runner
If you are using JUnit4, you can give this plugin a try:
https://plugins.jetbrains.com/plugin/12959-junit4-parallel-runner
Running tests in parallel is as easy as clicking on the green triangle next to a
class -> all the test methods in the class are run in parallel
package -> all the classes in the package are run in parallel

Related

Is it possible to start a test run of a JUnit 5 test class from within Java?

I found instructions on how to start a JUnit 4 test case from within Java, but have been unable to put together constructs that will fire up tests on a JUnit 5 test case.
The JUnit 4 solution I tried was this: How do I run JUnit tests from inside my java application?
I've been trying to get the ConsoleLauncher in JUnit5 to work, but it is throwing exceptions. That was documented here: http://junit.org/junit5/docs/current/user-guide/#running-tests-console-launcher
I'd like to automate starting tests to match running a program to simplify the instructions I'm providing when I provide unit tests to students.
Thanks!
If the goal is to simplify a task for students, I think it would be good to use a build tool like Maven or Gradle. This makes it simple to run tests, build their code, etc. JUnit5 tests can be run by using plugins - http://junit.org/junit5/docs/current/user-guide/#running-tests-build.

Is JUnit5 backward compatible to JUnit4?

I did google quite a bit; but I could neither find a source saying "of course it is" nor one going "no, it isn't; and here it breaks".
We have about 2000 unit tests of very varying quality, using EasyMock, PowerMock, Mockito; and I am simply wondering: is there a reasonable chance that those 2000 testcases just work when switching to JUnit5; or is that so unlikely that I better not spend a single second trying?
In other words: I am looking for answers that can confirm "yes, it worked for our large code base"; or "no, it is not at all that easy".
As stated by the JUnit 5 User Guide:
Just make sure that the junit-vintage-engine artifact is in your test runtime path. In that case JUnit 3 and JUnit 4 tests will automatically be picked up by the JUnit Platform launcher.
See the example projects in the junit5-samples repository to find out how this is done with Gradle and Maven.
http://junit.org/junit5/docs/current/user-guide/
junit-vintage-engine is for running junit4 or 3 so it looks like it
'JUnit Vintage test engine implementation that allows to run vintage JUnit tests, i.e. tests written in the JUnit 3 or JUnit 4 style, on the new JUnit Platform.'
My current assessment regarding regarding our projects is to stay with JUnit 4.12 for the moment.
As of now, we our build setup is "different" for eclipse and our "backend build"; meaning: we can't use maven/gradle to build within eclipse. And I simply failed to just identify/download the JARs I would need to replace the junit-4.12.jar within our eclipse setup; not even thinking about also providing some (but which) other JARs in order to have JUnit 5 available.

Intellij IDEA fork mode for unit tests slows down

I'm running 9 JUnit (Spockframework actually) tests in Intellij IDEA.
It takes about 3 seconds.
I want to make use of all of the cores, therefore I switch test configuration fork mode - class.
Edit configurations > Fork mode > class
This causes build time to grow to 8 seconds. Trying to use fork mode method makes it 22 seconds.
Also test runner process looks like they are being run sequentially instead of in parallel.
Any ideas on why doesn't forking tests work as expected?
Forking just means you will get a separate process for each test run, but the process wilt not necessarily run in parallel.
From what I've seen, the JUnit plugin does not have an option to run tests in parallel. If you're using Gradle, use the maxParallelForks option as shown in the docs (and you probably know it, but you can run Gradle tasks directly from IntelliJ).
If you use Maven, try the -t option.
You can give this plugin a try: https://plugins.jetbrains.com/plugin/16229-unit-test-parallel-runner
If you run unit tests in a single class, it runs all the test methods in parallel, if you run unit tests in many classes, it runs classes in parralel but methods in a single class are run in serial (it's faster this way unless you have a really high end machine).

How to enable processfork for unit tests in Gradle Android plugin

I have configured unit testing for AndroidStudio as described on the Android documentation (http://tools.android.com/tech-docs/unit-testing-support).
I would like to run every test method in its own JVM, so all static properties in my project are set back to their default values.
I couldn't find anything about this in the documentation and I'm afraid this is not possible yet.
I'm running my tests from the command line (gradlew --daemon test) as I didn't get the testrunner in Android Studio to work.
Does anyone know how to fork every testmethod in its own jvm process, so they run 'standalone'? Please let me know if this is possible or if there are alternative ways to run every testmethod in it's own process using gradle.
Thats easy. In your test task set
forkEvery 1
That will cause a new jvm to be forked for every single test.

What GUI should I run with JUnit(similar to NUnit gui)

What GUI should use to run my JUnit tests, and how exactly do I do that? My entire background is in .NET, so I'm used to just firing up my NUnit gui and running my unit tests. If the lights are green, I'm clean.
Now, I have to write some Java code and want to run something similar using JUnit. The JUnit documentation is nice and clear about adding the attributes necessary to create tests, but its pretty lean on how to fire up a runner and see the results of those tests.
JUnit stopped having graphical runners following the release of JUnit 4.
If you do have an earlier version of JUnit you can use a graphical test runner by entering on the command line[1]:
java junit.swingui.TestRunner [optional TestClass]
With the optional test class the specified tests will run straight away. Without it you can enter the class into the GUI.
The benefits of running your tests this way is that you don't have the overhead of an entire IDE (if you're not already running one). However, if you're already working in an IDE such as Eclipse, the integration is excellent and is a lot less hassle to get the test running.
If you do have JUnit 4, and really don't want to use an IDE to run the tests, or want textual feedback, you can run the text UI test runner. In a similar vein as earlier, this can be done by entering on the command line[1]:
java junit.textui.TestRunner [TestClass]
Though in this case the TestClass is not optional, for obvious reasons.
[1] assuming you're in the correct working directory and the classpath has been setup, which may be out of scope for this answer
Eclipse is by-far the best I've used. Couple JUnit with a code coverage plug-in and Eclipse will probably be the best unit-tester.
There's a standalone JUnit runner that has a UI, but I recommend using one of the builtin test runners in the Java IDEs (Eclipse, Netbeans, and IntelliJ all have good ones). They all support JUnit, and most support TestNG as well.
If you want a standalone test runner (not the build-in IDE one), then for Junit3 you can use
junit.textui.TestRunner %your_class% - command line based runner
junit.swingui.TestRunner [%your_class%] - runner with user interface (swing-powered)
For Junit4, the UI-powered runners were removed and so far I haven't found a convenient solution to run new Junit4 tests on old swing-powered runner without additional libraries. But you can use JUnit 4 Extensions that provides a workaround to use junit.swingui.TestRunner. More here
Why you need a GUI runner? Can't you just run the tests from the IDE itself?
In .Net we have TestDriven.net, in Java there must be something equivalent. You can check out IntelliJ IDEA, it has the unit testing support built-in.

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