I have spent certain efforts on multiple rounds and occasion in truly understanding subscribeOn and observeOn. After I examined the blog when-multiple-subscribeons-do-have-effect word by word with corresponding code snippet executed on my local laptop, I am relatively comfortable to say that now I get it.
However, what I still do not understand and I wish to obtain a deeper understanding is the relationship of TestScheduler#triggerActions and subscribeOn and observeOn.
I have created a dedicated pull request example here to demonstrate my confusion. It would be greatly appreciate that some expert in the community could provide insight to explain why or provide any example on how to write deterministic test code to assert subscribeOn and observeOn.