Tests for CollectionStream (#588)

* Add unit tests for core::nodes::NodeStream

* Move DummyMuxer to core/tests

* Address grumbles

* Impl Debug for SubstreamRef<P>

* Add test for poll()

* Don't need to open a substream

* pretty printer test

* More tests for NodeStream poll()

* ListenerStream unit tests: transport() and listeners()

* Tests for nodes/listeners.rs

* Add a few tests to help illustrate the "drowning" behaviour of busy listeners

* Tests for HandledNode

* Address grumbles

* Remove non-project specific stuff

* Address grumbles

* Prefer freestanding function

* Untangle the code for old shutdown test from the new tests
Add HandlerState and use it in TestBuilder
Shorter test names

* WIP – tests pass

* Use a newtype to lighten up the function signatures a bit
Test NotReady case

* Cleanup Event enum
Track events as they reach the Handler
Describe complex test logic

* Assert on the event trace

* More tests for poll()

* Switch to using usize as the OutboundOpenInfo so we can assert on event contents
More tests for poll()

* whitespace

* whitespace and spelling

* WIP tests for handled_node_tasks:Task

* wip

* Move Handler related code to dummy_handler

* Sort out the events going to/from node

* WIP tests for poll

* Add a TestBuilder for NodeTask tests
More NodeTask tests

* Fixes broken test after upstream changes

* Clarify the behaviour of is_shutting_down

* Fix broken test

* Test for task exit when muxers in- and outbound are closed

* Add question about impossible Async::NotReady

* Fix tests after recent changes on master

* Upstream changes

* Tests for HandledNodesTasks

* Add test for HandledNodesTasks poll

* Test we reach all nodes and then closed all nodes

* Test event emission by HandledNodesTasks

* Test starting CollectionStream

* Test that we can reach a peer after a successful connection

* Assert collection contains what we expect

* Test handler events get to the collectionstream

* Remaining tests for CollectionStream

* Run tests on single threaded runtime to avoid intermittent failures

* Remove call to shutdown – not needed

* No need to specify tokio version

* Rustfmt

* More rustfmt

* Less noise

* cleanup

* Address grumbles

* Better debug impl for HandledNodesTasks

* Remove tests for Task we don't need
Test Task.send_event() and id() using a HandledNodesTasks

* Rename test builders

* Don't organise tests in submodules

* whitespace

* Revert changes to Debug impl for HandledNodesTasks

* Cleanup

* cleanup

* Address concerns

* Fix tests

core/src/nodes/handled_node.rs

@@ -321,12 +321,9 @@ mod tests {
     use super::*;
     use tokio::runtime::current_thread;
     use tests::dummy_muxer::{DummyMuxer, DummyConnectionState};
-    use tests::dummy_handler::{Handler, HandlerState, InEvent, OutEvent};
+    use tests::dummy_handler::{Handler, HandlerState, InEvent, OutEvent, TestHandledNode};
     use std::marker::PhantomData;
 
-    // Concrete `HandledNode`
-    type TestHandledNode = HandledNode<DummyMuxer, Handler>;
-
     struct TestBuilder {
         muxer: DummyMuxer,
         handler: Handler,