Unhelpful error (ArgumentError: wrong number of arguments (1 for 0) when stubbing methods in classes that redefine public

[rspec]

Unhelpful error (ArgumentError: wrong number of arguments (1 for 0) when stubbing methods in classes that redefine public

[dchelimsky]

The public method takes 0 or 1 args: http://ruby-doc.org/core/classes/Module.html#M000448, but the example you provided doesn't accept any args, and is therefore in violation of Ruby's API. If you change the example to accept var args, it works fine:

class MyClass
  def self.public(*); nil; end

  def foo; bar; end
  def bar; "bar"; end
end

describe MyClass do
  it "should do the right thing" do
    instance = MyClass.new
    instance.should_receive :bar
    instance.foo
  end
end

[hjdivad]

David,

First, thank you for the prompt response.

You are right about public, but my example is contrived for readability. The actual problem I ran into was in trying to test a Sinatra app.

From sinatra 1.2.0

# sinatra 1.2.0 lib/sinatra/base.rb

# lines 1267..1270
def metadef(message, &block)
  (class << self; self; end).
    send :define_method, message, &block
end


# lines 925..940 (edited for clarity)
def set(option, value=self, &block)
  # ...
  metadef(option, &value)
  metadef("#{option}?") { !!__send__(option) }
  metadef("#{option}=") { |val| metadef(option, &Proc.new{val}) }
  self
end

# line 1357
set :public, Proc.new { root && File.join(root, 'public') }

Is your position that this is a bug in Sinatra and a WONTFIX for rspec-mocks?

[dchelimsky]

@hjdivad - yes, that's my position. It doesn't make sense that RSpec (or any other library) should have to check whether core Ruby APIs are in place and functioning as advertised.

[hjdivad]

@dchelimsky Fair enough. Thanks again.

[jhulten]

(Commenting here for those that Google the issue)

If you do modular sinatra apps this seems to be a workaround... Let me know if you see any big issues.

    class << self
      alias_method :sinatra_public, :public
    end

    (class << self; self; end).send :define_method, :public, ::Module.instance_method(:public)