MPI-JUnit

MPI-JUnit [1] is a JUnit 4 Runner which allows you to write and configure tests for MPI programs. By simply adding Java annotations, your test classes will be executed as an MPI program.

@RunWith(MpiRunner.class)  // Use the MpiRunner to run the test
@MpiConfig(ranks=4)        // Specify how many ranks you want your test to run with
public class MyTestClass {
	@Test
	public void testMultipleHosts() {
		assertTrue(MPI.COMM_WORLD.Size() > 1);
	}
}

Dedicated website 

Custom Junit4 runner - the general idea

Using a custom Junit runner, instead of calling the Test methods “directly”, you can launch your custom command using a ProcessLauncher. In my implementation, I made every MPI process use the normal Junit4 runtime to run the test methods. However, instead of using the normal RunNotifier of the Junit runtime, the MPI processes use my custom ToFileRunNotifier which writes the calls it receives to a file. A file with the calls received from each rank is saved before the MPI process that ran the test class completes.

Back in my custom runner, I aggregate the results of each test method of each MPI process and transmit those to the normal RunNotifier.

Benefits

With this system, you are staying within the “normal” Junit4 framework. In my case I was trying to run Junit tests from Maven. I can also integrate the test results with the Eclipse Junit view successfully. Here is a capture of my Eclipse environment after running the tests.

Acknowledgment

This project was made possible with the help of some StackOverflow users who took the time to respond to my questions and or had posted related questions:

• Running unit tests with mpirun using ant
• Transmitting Java agents instrumentation to spawned JVM
• Surefire Maven plugin: “Corrupted STDOUT by directly writing to native stream in forked JVM”