Threading-related Limitations of PublishedEvents

[aahlenst]

I'm dealing with an application that emits application events in response to WebSocket messages. Those are published on Tomcat's handler threads (for example, tomcat-handler-9) and never captured by PublishedEvents. If I ensure that the same code runs on the same thread as the test, PublishedEvents captures them.

While Modulith's documentation does not say much about threading, #116 suggests that PublishedEvents can only capture events emitted by the same thread the test runs on and its descendants. Seemingly, Tomcat's handler threads in a @SpringBootTest are not descendants of the test thread. The same seems to be true for @Scheduled. With an Executor, it seems to depend on when and where the task is submitted. For example, events submitted in a construtor are not captured while those submitted in a method directly invoked from the test are.

Is my interpretation of the situation correct? If so, is this an expected (or desired) limitation of PublishedEvents? Is there a recommended workaround?