From: ara.t.howard@...
Date: 2007-01-04T10:15:50+09:00
Subject: Re: Problem in Unit Testing Methods that start new threads

On Thu, 4 Jan 2007, Hemant Kumar wrote:

>
> Agreed Pit, but basically I want to test state of my program through
> Unit Tests and whether each method modifies state of program as it was
> intended?
>
> Now, unit testing methods that return something on invocation is easy
> and i don't need to go around running asserts on instance variables.
>
> But I have some doubt regarding testing methods that don't return
> anything explicitly and rather update instance variables.
>
> Earlier, I was writing Unit Tests for a networking application which i
> wrote using EventMachine. Now since, EM is completely based on
> callbacks, you can't do a check on return values of methods. Hence I had
> to rely on doing asserts on instance variables.
>
> I would love to know, how do i go about unit testing in such cases. I
> can't yet grasp concept of code that can be unit tested easily i guess.
>

often methods should do one of two things:

   - succeed or throw an exception

   - return a value indicating success

in your case the former should be sufficient - you can assert that nothing is
raised and move on.  if that's not sufficient consider changing the way your
method works: testing internal state is, at least, going to make maintaining
your tests very very hard since they're so cozy with your impl.

cheers.

-a
-- 
if you find yourself slandering anybody, first imagine that your mouth is
filled with excrement.  it will break you of the habit quickly enough. - the
dalai lama