Main problem with early-terminated.drain test with fs 2.x.x is that .onFinalize in takeThroughDrain executed after last Stream.eval(queue.dequeue1). I dont know why. I've not found answer even in fs2 gitter. Maybe it's a bug maybe it's a feature. But I've found workaround. If there is .onFinalize{IO.unit} after usage oftakeThroughDrain then all goes as expected. This can be seen in scastie example. So I've fixed all tests and usages of takeThroughDrain with account of the workaround.