From: Avdi Grimm <Avdi_B_Grimm@...>
Date: 2005-04-14T09:00:49+09:00
Subject: Mocking out a class object


Okay, I'm trying to mock up a class object.  It needs to do two
things:

1. Respond to #new with a object *I* provide, rather than a new
   instance of the class; and
2. Contain a constant, such that code containing 'MyMockClass::FOO'
   will work.

I can think of a naive implementation:

    class MyMockClass
        FOO="some value"
        def self.set_instance(inst)
            @instance=inst
        end
        def self.new(*)
            return @instance
        end
    end

I'm wondering, though, is there a way to do this inline with
metaprogramming, and avoid defining the set_instance method?  I've
tried something like this:

    my_instance=...

    Class.new :MyMockClass {
        const_set :FOO, "some value"
        define_method(:new) do |*|
            return my_instance
        end
    }

But that doesn't work, because the define_method is creating an
instance method, not a class method.  I've also tried to use a regular
old object, instead of a class object, but then the constant (FOO)
doesn't work.  Any ideas?
    
-- 
ABG