Kafka streams with chained emitStrategy(onWindowClose) example does not work

[gregfichtenholtz-illumio]

Hi, I got this example by using the following prompt in Google:

1. kafka streams unit testing with chained "emitStrategy"
2. Provide an example of testing chained suppress with different grace periods

https://gist.github.com/gregfichtenholtz-illumio/81fb537e24f7187e9de37686bb8eca7d

Compiled and ran the example using latest kafka jars only to get

[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.103 s <<< FAILURE! -- in com.k8sflowprocessor.ChainedEmitStrategyTopologyTest
[ERROR] com.foo.bar.ChainedEmitStrategyTopologyTest.testChainedWindowedAggregationsWithDifferentGracePeriods -- Time elapsed: 1.096 s <<< FAILURE!
org.opentest4j.AssertionFailedError: Final output should contain one result ==> expected: <1> but was: <0>
at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:158)
at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:139)
at org.junit.jupiter.api.AssertEquals.failNotEqual(AssertEquals.java:201)
at org.junit.jupiter.api.AssertEquals.assertEquals(AssertEquals.java:168)
at org.junit.jupiter.api.Assertions.assertEquals(Assertions.java:694)
at com.foo.bar.ChainedEmitStrategyTopologyTest.testChainedWindowedAggregationsWithDifferentGracePeriods(ChainedEmitStrategyTopologyTest.java:123)

It appears that the test is not able to drive the kafka stream to emit the 2nd event.
Could be a bug in test code/test driver/kafka streams?
Thanks in advance
Greg