Can't specify the arguments to initialize

[zephyr-dev]

It'd be nice if you could specify the arity of initializing a duck type.

I tried just defining an initialize method in the interface module:

module Quacky::Interfaces
  module ActivityFeedItem
    def initialize(item, view_context); end
  end
end

but now I get

    Failure/Error: it { should quack_like Quacky::Interfaces::ActivityFeedItem }
     ArgumentError:
       wrong number of arguments (0 for 2)
     # ./spec/support/interfaces/activity_feed_item.rb:3:in `initialize'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/quacky-0.2.7/lib/quacky/duck_type_verifier.rb:41:in `new'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/quacky-0.2.7/lib/quacky/duck_type_verifier.rb:41:in `duck_type_object'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/quacky-0.2.7/lib/quacky/duck_type_verifier.rb:32:in `duck_type_methods'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/quacky-0.2.7/lib/quacky/duck_type_verifier.rb:10:in `verify!'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/quacky-0.2.7/lib/quacky/rspec_setup.rb:14:in `block (3 levels) in <top (required)>'
     # /Users/pivotal/.rvm/gems/ruby-1.9.3-p327/gems/rspec-expectations-2.12.1/lib/rspec/matchers/extensions/instance_eval_with_args.rb:11:in `instance_exec'

[benmoss]

Turns out to be slightly difficult because initialize is considered private. Not sure what the best solution would be, maybe special-casing initialize? It is the one private method that is still pretty much guaranteed to be part of the public contract, in the sense that its arity matters.

[squeedee]

It would have to be a special case where you use instance_method instead of public_method.

Only problem I see, anyone using quacky who hasn't worried about initialize, but the initialize of the test class has arity > 0, would suddenly get an arity error.

You can't tell if the Interface module specified the initialize or not - if its not defined, it's there with an arity of 0.