testing asynchronous code

[Tim Fletcher]

> I take it the basic idea is to unit test all the underlying
> synchronous code separately, and then assert that if the
> low-level code works, and all the casts are going out as
> specified, then the high-level code is correct?

Yes. By replacing your gen_server with a test double you can
programmatically test your high-level calling code independently from
your low-level synchronous code.

Tim