When writing my own Akka Streams stages I’m finding it quite difficult to test that they pull / backpressure under the correct situations.
The main problem is that
TestSource is a detached stage and inserts an async boundary between itself and my stage. This seems to be stemming from the fact that
SourceModule which wraps it in an island.
The only workaround I have found is to change the buffer size to
1 and then I have to remember to ignore the first request. This seems to work but can be a bit cumbersome.
I’m a little surprised that this isn’t more of a problem. Is there some other approach to testing backpressure that I am no aware of?