How to enable debug on my JUnit through Gradle test task

Question

I get into trouble while I try to run my JUnit test through Gradle test task. While I run the test in eclipse directly with Run As -> JUnit test, everything is ok, the test succeeds. But through test task, test always fails. Probably some trouble with the encoding of my resource txt file. So I would like to enable debug while I am launching the test with Gradle

in build.gradle, my test task now looks like:

test {
    tasks.withType(Compile) {
        options.encoding = 'UTF-8'
    }
}

So what should I do to enable debug? I run Gradle tasks from Gradle panel in Eclipse, not from the console. Thanks!

Solution 1

To debug tests the following argument should be used: --debug-jvm

For example: gradle test --debug-jvm
Gradle will suspend execution right before running tests and wait for debugger connection on port 5005.

For executing only specific tests see Simple name pattern

For additional options see Debugging when running tests.

Solution 2

As explained under 23.12. Test in the Gradle User Guide, executing gradle test -Dtest.single=MyTestClass -Dtest.debug will suspend the test JVM upon start, and allows to connect an external debugger (such as the Eclipse debugger) on port 5005.

Solution 3

Putting this here as --debug-jvm did not work for me, I was able to do this by setting:

 org.gradle.daemon=true
 org.gradle.jvmargs=... -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=10999

in

 ~/.gradle/gradle.properties

But when I connect with eclipse debugger for the project none of the breakpoints I've set compile/trigger... I am connected via the debugger, I can see action in the Debug view, whenever I run gradle test from command line, like new threads starting/stopping, but can't get breakpoints to trigger, trying to resolve this now...

Fyi to stop deamon run gradle --stop

Other solution

Leaving above as reference, this worked for triggering break points in tests, I turned off deamon as I could not get it to work properly:

Using directions from this article: http://blogs.steeplesoft.com/posts/2013/gradle-tip-attaching-a-debugger.html

test {        
    if (System.getProperty('DEBUG', 'false') == 'true') {
        jvmArgs '-Xdebug',
            '-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=10999'
    }
}

Executed via gradle test -DDEBUG=true

Solution when using the JUnit Platform Gradle plugin

The solution above won't work when using org.junit.platform.gradle.plugin.

Instead it should be replaced by:

junitPlatformTest {        
    if (System.getProperty('DEBUG', 'false') == 'true') {
        jvmArgs '-Xdebug',
            '-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=10999'
    }
}

Solution 4

I'm on 4.6 (gradle) and I'm able to debug my tests when I have this in my build.gradle file:

test {
    debug true
}

Link - https://docs.gradle.org/4.6/userguide/userguide_single.html#sec:java_test

View more solutions

Comments

[Peter Niederwieser]

This configuration doesn't affect the test task but all Compile tasks. Hence it shouldn't be nested inside test { .. }.

[mefi]

In some test classes (and also in regular java classes), there are some constant strings with diacritics, so I need to run test with UTF-8 encoding. While I used this, tests who failed before now runs ok. If you say this is not ok, could you help me how to correct this (While i keep diacritics string in java classes)? Use this encoding only on tests?

[Peter Niederwieser]

If you want to set the encoding for all JavaCompile tasks, use tasks.withType(JavaCompile) { options.encoding = 'UTF-8' }. If you only want to set it for test compilation, use compileTestJava { options.encoding = 'UTF-8' }. (Compile has been deprecated and is now called JavaCompile.)

[mefi]

Thank you, is it possible to use it directly from Eclipse?

[Peter Niederwieser]

Depends on what exactly you mean by that. From what I remember, the Eclipse Gradle tooling does support custom command line parameters, so it should be possible to start the build from Eclipse. Then you'll have to fire up the Eclipse debugger.

[mefi]

Fine, I`ll try it. Thank you very much!

[RuntimeException]

Thanks Peter. In case where I am unable to use port 5005, how do I disable fork of test JVM. Or change the port number to something else other than 5005?

[Robin Green]

Firstly, that's usually called an "option", not an "attribute". Secondly, it doesn't work for me to just prepend it to the command line arguments - it's necessary to append it.

[niken]

This did not work for me at all... I am able to connect with a debugger in deamon mode but none of my breakpoints compile/trigger in eclipse... this feature is kind of weak sauce

[Sergey]

Since you enabled daemon, there are two JVMs running. You are connecting to the wrong one.

[niken]

2 jvms listening on 1 port? How can that be? I don't think I was connecting to wrong jvm, deamon was registering all calls to gradle, from eclipse or command line client... Like I said I saw it "doing stuff" in debugger whenever I ran any gradle command

[nilskp]

@Nik, the reason it's not working is that Eclipse does it's own build in the bin/ folder, which is where it attaches the breakpoints. Gradle also builds to build/classes/, which is the classfiles it runs. Thus not working.

[Thomas W]

If you have difficulty with build-tool options, you can capture & reproduce the process launch and configure that to attach your debugger. literatejava.com/engineering/how-to-debug-tests-run-external‌​ly

[Vic Seedoubleyew]

Doesn't seem to work at all for me using using Gradle 4.4.1, it doesn't seem to notice it at all

[Vic Seedoubleyew]

This doesn't work when using org.junit.platform.gradle.plugin, in which case the second part of that answer should be used : stackoverflow.com/a/38210920/2873507

[Vic Seedoubleyew]

This doesn't work when using org.junit.platform.gradle.plugin, in which case the second part of that answer should be used : stackoverflow.com/a/38210920/2873507

[romeara]

Newer versions of Gradle have a specific DSL, independent of test framework, documented in the current Gradle version user guide

[Roland Puntaier]

This will listen on port 5005. You can then jdb -sourcepath <...> -attach 5005 and stop at com.<...>.<TestClass>:<line number>. test {debug true} is top level in build.gradle.