Java Extreme Programming Cookbook

Creating a LoadTest

Problem

You need to make sure that code executes correctly under varying load conditions, such as a large number of concurrent users.

Solution

Decorate an existing JUnit Test with a JUnitPerf LoadTest.

Discussion

A JUnitPerf LoadTest decorates an existing JUnit test to simulate a given number of concurrent users, in which each user may execute the test one or more times. By default, each simulated user executes the test once. For more flexibility, a load test may use a com.clarkware.junitperf.Timer to ramp up the number of concurrent users during test execution. JUnitPerf provides a ConstantTimer and RandomTimer to simulate delays between user requests. By default all threads are started at the same time by constructing a ConstantTimer with a delay of zero milliseconds.

Tip

If you need to simulate unique user information, each test must randomly choose a different user ID (for example). This can be accomplished using JUnit’s setUp( ) method.

Here is an example that constructs a LoadTest with 100 simultaneous users:

public static Test suite(  ) {
    Test testCase = new TestSearchModel("testAsynchronousSearch");
    Test loadTest = new LoadTest(testCase, 100);
    TestSuite suite = new TestSuite(  );
    suite.addTest(loadTest);
    return suite;
}

Here is an example that constructs a LoadTest with 100 simultaneous users, in which each user executes the test 10 times:

public static Test suite( ) { Test testCase = new TestSearchModel("testAsynchronousSearch"); Test loadTest = new LoadTest(testCase, ...