From: Robert Klemme <bob.news@...>
Date: 2005-03-15T23:01:21+09:00
Subject: Re: Mocking new and other class methods


"jeem" <jeem.hughes@gmail.com> schrieb im Newsbeitrag 
news:1110831120.593168.314560@o13g2000cwo.googlegroups.com...
> Hello group.  I wanted to be able to do something like this:
>
> def testItResizesTheImage
>  imageNew=ClassMethodMocker.new(Magick::Image,:new)
>  image=FlexMock.new
>  imageNew.handle { |imagePath| assert_equal(@imagePath,imagePage);
> image }
>  image.mock_handle(:somecall) { |etc| etc }
>  # etc
>  test_subj.doThatThing
>  image.mock_verify
>  imageNew.verify
> end
>
> So, I wrote a few loc to enable it (borrowing from FlexMock) for 'new'
> calls at least.  I'm having second thoughts about how I implemented it,
> so I was hoping some in the ng might want to kick it around.
>
> My big concern with the current method (see below) is that the real new
> might not be "put back" if a coder doesn't use MockNew.use.

Blocks with ensure could help here as transactional context.

> I have other ways in mind to allow mocking of class methods, but they
> all seem to put up new hoops for coders to jump through, and make the
> resulting code less natural.

Sorry, I'm not really sure what you're after.  What I extracted from your 
code is that you iterate through a set of new methods and use the original 
one in the end.  IMHO you can get that with much less effort and less meta 
programming:

class MockClass
  def initialize(cl, *handlers)
    @cl = cl
    @handlers = handlers
    @idx = 0
  end

  def new(*a)
    h = @handlers[@idx]

    if h
      @idx += 1
      h.call(*a)
    else
      @cl.new(*a)
    end
  end
end

cl_fake = MockClass.new(String,
  lambda {|*a| "1"},
  lambda {|*a| "2"} )

>> cl_fake.new "a"
=> "1"
>> cl_fake.new "a"
=> "2"
>> cl_fake.new "a"
=> "a"
>> cl_fake.new "a"
=> "a"
>> cl_fake.new "a"
=> "a"

Kind regards

    robert