How to set JVM parameters for Junit Unit Tests

Question

I have some Junit unit tests that require a large amount of heap-space to run - i e  1G   They test memory-intensive functionality for a webstart app that will only run with sufficient heap-space  and will be run internally on Win 7 64-bit machines - so redesigning the tests isn t a practical suggestion    I am developing in Intellij IDEA  so I know I can set the JVM parameters  e g  -Xmx1024M  for the test class  However  this is only for running the whole test class - if I want to run an individual test  I have to recreate the run congfigurations for that test method    Also  those are IDE and box specific - so if I switch boxes  I develop on multiple machines  or one of my colleagues tries to run the tests  those settings are not transferred   Also  other IDEs like Eclipse and NetBeans are used by my colleagues   FWIW  we re using mercurial for source code control   For the build cycle  we re using Maven  so I know how to specify the JVM parameters for that   So  - I m looking for a way of specifying the JVM parameters that will apply for the whole test class and the individual test methods  and - I d like to share those specification across IDEs on any machine  having picked up the code from the repository

User · Answer

If you set it in Java code  you can set it like this       static           System getProperties   setProperty  quot env quot    quot test quot            System getProperties   setProperty  quot spring application name quot    quot spring-example quot           reference  https   stackoverflow com a 60654275 4712855 https   stackoverflow com a 10774432 4712855

User · Answer

In Maven you can configure the surefire plugin   lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-surefire-plugin lt  artifactId gt       lt version gt 2 9 lt  version gt       lt configuration gt           lt argLine gt -Xmx256M lt  argLine gt       lt  configuration gt   lt  plugin gt    If you use Maven for builds then this configuration will be carried in the source tree and applied when tests are carried out  See the Maven Surefire Plugin documentation

User · Answer

In IntelliJ you can specify default settings for each run configuration  In Run Debug configuration dialog  the one you use to configure heap per test  click on Defaults and JUnit  These settings will be automatically applied to each new JUnit test configuration  I guess similar setting exists for Eclipse   However there is no simple option to transfer such settings  at least in IntelliJ  across environments  You can commit IntelliJ project files to your repository  it might work  but I do not recommend it   You know how to set these for maven-surefire-plugin  Good  This is the most portable way  see Ptomli s answer for an example    For the rest - you must remember that JUnit test cases are just a bunch of Java classes  not a standalone program  It is up to the runner  let it be a standalone JUnit runner  your IDE  maven-surefire-plugin to set those options  That being said there is no  portable  way to set them  so that memory settings are applied irrespective to the runner   To give you an example  you cannot define Xmx parameter when developing a servlet - it is up to the container to define that  You can t say   this servlet should always be run with Xmx 1G

User · Answer

According to this support question https   intellij-support jetbrains com hc en-us community posts 206165789-JUnit-default-heap-size-overridden-  the -Xmx argument for an IntelliJ junit test run will come from the maven-surefire-plugin  if it s set   This pom xml snippet           lt plugin gt               lt groupId gt org apache maven plugins lt  groupId gt               lt artifactId gt maven-surefire-plugin lt  artifactId gt               lt configuration gt                   lt argLine gt -Xmx1024m lt  argLine gt               lt  configuration gt           lt  plugin gt    seems to pass the -Xmx1024 argument to the junit test run  with IntelliJ 2016 2 4

User · Answer

You can use systemPropertyVariables  java protocol handler pkgs is your JVM argument name     lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-surefire-plugin lt  artifactId gt       lt version gt 2 12 4 lt  version gt       lt configuration gt           lt systemPropertyVariables gt               lt java protocol handler pkgs gt com zunix base lt  java protocol handler pkgs gt               lt log4j configuration gt log4j-core properties lt  log4j configuration gt           lt  systemPropertyVariables gt       lt  configuration gt   lt  plugin gt    http   maven apache org surefire maven-surefire-plugin examples system-properties html

User · Answer

I agree with the others who said that there is no simple way to distribute these settings    For Eclipse  ask your colleagues to set the following    Windows Preferences   Java   Installed JREs  Select the proper JRE JDK  or do it for all of them  Edit Default VM arguments  -Xmx1024m Finish  OK    After that all test will run with -Xmx1024m but unfortunately you have set it in every Eclipse installation  Maybe you could create a custom Eclipse package which contains this setting and give it to you co-workers   The following working process also could help  If the IDE cannot run a test the developer should check that Maven could run this test or not    If Maven could run it the cause of the failure usually is the settings of the developer s IDE  The developer should check these settings  If Maven also could not run the test the developer knows that the cause of the failure is not the IDE  so he she could use the IDE to debug the test

User · Answer

Parameters can be set on the fly also     mvn test -DargLine  -Dsystem test property test    See http   www cowtowncoder com blog archives 2010 04 entry 385 html

User · Answer

An eclipse specific alternative limited to the java library path JVM parameter allows to set it for a  specific source folder rather than for  the whole jdk as proposed in another response     select the source folder in which the program to start resides  usually source test java  type alt enter to open Properties page for that folder select native in the left panel Edit the native path  The path can be absolute or  relative to the workspace  the second being more change resilient    For those interested on detail on why maven argline tag should be preferred to the systemProperties one  look  for example    Pick up native JNI files in Maven test  lwjgl

[java] How to set JVM parameters for Junit Unit Tests?

Examples related to java

Examples related to unit-testing

Examples related to junit

Examples related to jvm

Examples related to intellij-idea