Running JUnit tests in parallel with Maven

A little-known but very useful feature slipped into JUnit 4 and recent versions of the Maven Surefire Plugin: support for parallel testing. This feature has been around for a while in TestNG, but has been missing in JUnit. And now, if you are a JUnit user, you too can run your tests in parallel! Running your tests in parallel is a powerful way to speed up your tests. Good automated tests should be independent, isolated and reproducible, making them ideal candidates for being run concurrently. However in practice not all test classes are designed with concurrency in mind, and aspects such as shared mutable instance variables, shared file or database access, or the use of embedded web servers may make running the tests in parallel trickier. Nevertheless, running your tests in parallel is decidedly a very neat trick! Let's see how it works. As of JUnit 4.7, you can configure Maven to run your tests in parallel, just like in TestNG. The following configuration will run your test methods in parallel: org.apache.maven.plugins maven-surefire-plugin 2.5 methods Another useful trick is to run your test classes in parallel, rather than the methods. You can do this by setting the configuration item to 'classes' instead of 'methods'. This may or faster depending on the number of test classes you have, but it might also be safer for some test cases not designed with concurrency in m...

Date: July, 07 2010
Url: http://www.java.net/blog/johnsmart/archive/2010/07/06/running-junit-tests-parallel-maven

Others News