[Caml-list] Unit testing Core Async

[Kenneth Adam Miller <kennethadammiller@gmail.com>]

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I've noticed that Core Async requites that a Scheduler.go () call be
placed-but that never returns. I have a Tcp.server that I'm creating, and I
like to use oUnit for my tests. Monads and all are beautiful, and Core is a
wonderful library, but I'm adamant that I have at least some minimal
functionality testing complete that demonstrates proper behavior as well as
intended usage.

What I'm wondering is the following: would there be a way to have the
scheduler.go call be placed in order to fire things off, but in another
thread have all the test code be dependent on the server's responses and
all of that, so that once completed, it can call Shutdown.shutdown?

I tried this out, and it introduced some issues.

First, I think that my shutdown call got executed before the unit test was
able to complete. This is because using Async's Deferred introduces some
complication if you want behavior to proceed sequentially as in without
building deeply nested callback chains. What I'm used to is asynchronous
send, and blocking receive that operates on a common execution chain. I
don't see any kind of Deferred.await that blocks until the instance
resolves (yes, there's upon, but that's just nesting again because it
returns another deferred.

Second, I think shutdown shuts *everything* down. What I need is just to
signal the completion of the job that was supposed to run, so that the
Scheduler.go returns in order to allow my unit tests to run to completion.

Third, I'm not certain about the semantics of Pipe/Reader/Writer. It's not
behaviorally like what I'm familiar with. For instance, callbacks may
return prematurely and only have part of a message. In ZMQ, what you send
is what you get. So that makes me concerned in regards to the Tcp.Server,
because right now what I need is for the Pipe to just allow blocking
receive so that I can make the threads coordinated, but I need the Tcp
Server to allow me to receive whole protobuf messages.

Can anyone please help me?

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