The LoadTest is a test decorator that runs
a test with a simulated number of concurrent users and
iterations.
In its simplest form, a LoadTest is constructed
with a test to decorate and the number of concurrent users.
For example, to create a load test of 10 concurrent users
with each user running ExampleTest once and
all users started simultaneously, use:
Test loadTest = new LoadTest(new TestSuite(ExampleTest.class), 10);
or, to load test a single test method, use:
Test loadTest = new LoadTest(new ExampleTest("testSomething"), 10);
The load can be ramped by specifying a pluggable
Timer instance which prescribes the delay
between the addition of each concurrent user. A
ConstantTimer has a constant delay, with
a zero value indicating that all users will be started
simultaneously. A RandomTimer has a random
delay with a uniformly distributed variation.
For example, to create a load test of 10 concurrent users
with each user running ExampleTest.testSomething() once and
with a one second delay between the addition of users, use:
Timer timer = new ConstantTimer(1000);
Test loadTest = new LoadTest(new ExampleTest("testSomething"), 10, timer);
In order to simulate each concurrent user running a test for a
specified number of iterations, a LoadTest can be
constructed to decorate a RepeatedTest.
Alternatively, a LoadTest convenience constructor
specifying the number of iterations is provided which creates a
RepeatedTest.
For example, to create a load test of 10 concurrent users
with each user running ExampleTest.testSomething() for 20 iterations,
and with a one second delay between the addition of users, use:
Timer timer = new ConstantTimer(1000);
Test repeatedTest = new RepeatedTest(new ExampleTest("testSomething"), 20);
Test loadTest = new LoadTest(repeatedTest, 10, timer);
or, alternatively, use:
Timer timer = new ConstantTimer(1000);
Test loadTest = new LoadTest(new ExampleTest("testSomething"), 10, 20, timer);
A LoadTest can be decorated as a TimedTest
to test the elapsed time of the load test. For example, to decorate
the load test constructed above as a timed test with a maximum elapsed
time of 2 seconds, use:
Test timedTest = new TimedTest(loadTest, 2000);
By default, a LoadTest does not enforce test
atomicity (as defined in transaction processing) if its decorated
test spawns threads, either directly or indirectly. In other words,
if a decorated test spawns a thread and then returns control without
waiting for its spawned thread to complete, then the test is assumed
to be transactionally complete.
If threads are integral to the successful completion of
a decorated test, meaning that the decorated test should not be
treated as complete until all of its threads complete, then
setEnforceTestAtomicity(true) should be invoked to
enforce test atomicity. This effectively causes the load test to
wait for the completion of all threads belonging to the same
ThreadGroup as the thread running the decorated test.
author:
Mike Clark
author:
Clarkware Consulting, Inc.
author:
Ervin Varga | 