HI :) I have finally figured it out :) On top of changes from last email, in my test method, I had to wrap "testHarness.processElement" in synchronized block, like this:
@Test public void foo() throws Exception { synchronized (this.testHarness.getCheckpointLock()) { testHarness.processElement(MyMessage.builder().build(), 1L); } } That worked. I think that this could be added to official documentation in [1]. [1] https://ci.apache.org/projects/flink/flink-docs-stable/dev/stream/testing.html -- Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/