From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2001-11-22T19:32:43+09:00
Subject: [ruby-talk:26125] Dynamic programming and Unit Testing.

I'm trying to understand how to use the dynamic featurs of Ruby
to good effect, together with encapsulation.

I have a base class that is pretty much virtual, so that in use
it will always be subclassed.  Let's call it Knot for now.
So I will want to do increasingly sophisticated tests on it, with
things like

class ThumbKnot < Knot
 ...
end

class ReefKnot < Knot
  ...
end

class AlpineButterflyKnot < Knot
   ...
end


Ideally, I would create these in my testing classes, so that each test
is distinct, the information relating to the test is held locally to it,
and is Protected (in the inheritance sense).

However, one cannot define a class in a method.  This presumably relates
to class names being constants, but I'm not sure.  Futhermore, one
cannot define methods within a method definition.  I can create
singleton classes, ("class << aknot") but these are not proper
subclasses.

I think I can nest class definitions so long as I'm not in a method:

class This
    class That
    end
end

so this may solve my problem.

So do I do something like:

class  Testing_Knot_with_ThumbKnot < RUNIT::TestCase
     class ThumbKnot < Knot
         def tie
         end
     end
     def test_ThumbKnot
     end
end


and so on?

I think I need to know a bit more explicitly what the nesting
rules are for these things, and whether there is some simple underlying
principle that would make such rules easy to remember.

	Thank you,
	Hugh