I'd like to write a unit test to verify that optimistic locking is properly set up (using Spring and Hibernate).

I'd like to have the test class extend Spring's AbstractTransactionalJUnit4SpringContextTests.

What I want to end up with is a method like this:

@Test (expected = StaleObjectStateException.class) 
public void testOptimisticLocking() {
    A a = getCurrentSession().load(A.class, 1);
    a.setVersion(a.getVersion()-1);
    getCurrentSession().saveOrUpdate(a);
    getCurrentSession().flush();           
    fail("Optimistic locking does not work");
}

This test fails. What do you recommend as a best practice?

The reason I am trying to do this is that I want to transfer the version to the client (using a DTO). I want to prove that when the DTO is sent back to the server and merged with a freshly loaded entity, saving that entity will fail if it's been updated by somebody else in the meantime.