Using easymock in multithreading

Question

I want to test that some method would be recalled on failing. Calling executed in separate thread. So I write code like this

final Foo mock = createStrictMock(Foo.class);

mock.bar();
expectLastCall().andThrow(new RuntimeException("TEST EXCEPTION"));
mock.bar();
replay(mock);

doStuff();
sleepSomeTime(); //Pretty dirty. But I need to test it in multithreading.
verify(mock);

And test passed. But I did not implement recall yet.

To make test fail, I replaced

 mock.bar();
 expectLastCall().andThrow(new RuntimeException("TEST EXCEPTION"));

with

 mock.bar();
 expectLastCall().andAnswer(new IAnswer<Void>() {
        @Override
        public Void answer() throws Throwable {
            sleepSomeTime();
            throw new RuntimeException("TEST EXCEPTION");
        }
    });

But I don't like adding sleepSomeTime all around my tests. Beside that, I don't actually understand while it helps in this particular case. So,

Why adding delay helped?

What the right way to do such stuff?

Answer 1

My approach has been to use locks. There isn't quite enough info in your post to show something definitive, but it'd probably look something like this:

final Lock lock = new Lock();
lock.lock();
expectLastCall().andAnswer(new IAnswer<Void>() {
    @Override public Void answer() throws Throwable {
        lock.unlock();
        throw new RuntimeException("TEST EXCEPTION");
    }
});     
doStuff();
lock.lock();
verify(mock);

The gist here is the second lock() invocation is blocked until the unlock in your mock frees up the lock.