Problem with nested associations and instance_eval?

[jcbpl]

I have blueprints.rb set up like this:

Channel.blueprint do
  name
  short_name
  description
end

Post.blueprint do
  channel
  title
  body
end

Attachment.blueprint do
  post
end

This works fine except in calling Attachment.make. I consistently receive the following error:

ArgumentError in 'Attachment should belong to post'
wrong number of arguments (0 for 1)
/Users/jakepaul/Projects/chirp/spec/blueprint.rb:26:in `post'
/Users/jakepaul/Projects/chirp/spec/blueprint.rb:26:
/Users/jakepaul/Projects/chirp/vendor/plugins/machinist/lib/machinist.rb:20:in `instance_eval'
/Users/jakepaul/Projects/chirp/vendor/plugins/machinist/lib/machinist.rb:20:in `run'
/Users/jakepaul/Projects/chirp/vendor/plugins/machinist/lib/machinist/active_record.rb:52:in `make'
./spec/models/attachment_spec.rb:7:

I've been troubleshooting for awhile and I think it must have something to do with the way the instance_eval works. Replacing post in the Attachment.blueprint block with post_id {2} causes it to work, and I can call Attachment.make{:post => post} successfully in the spec.

If I replace the has_many/belongs_to relationship between Post and Attachment with one between Channel and Attachment (so attachments belong to a Channel instead of a Post), the relationship works as expected. This leads me to suspect that there may be a problem with nesting the relationship (Attachment belonging to Post belonging to Channel) and possibly with instance_eval, but I'm not experienced enough with instance_eval to know why or how to fix it.

Thank you in advance!

[jcbpl]

Update: Running script/console in the test env and then requiring spec/blueprint, this problem does not seem to occur. Attachment.make works and it creates a post properly (and the post has an associated channel). Any idea what might be causing this?

[notahat]

The code above looks fine to me, and I do similar things in a couple of apps.

If you give me some runnable code that demonstrates the failure, I'm happy to have a look.

[jcbpl]

I figured it out. I was including ActionController::TestProcess in order to use fixture_file_upload, but that also included a method named post. So it thought I was trying to call the method.

I had guessed that it might be something like that but I was not making the connection to ActionController::TestProcess. Thank you very much, though! I really like machinist.