let(:message) overrides the message method in Minitest::Assertions

[ericbock]

If I define let(:message) { mock_model(Message).as_null_object } and have an example that asserts my controller should redirect_to then I receive a wrong number of arguments (1 for 0) error. I'm using ruby 1.9.1p429, rails 3.0.0.rc and rspec-rails 2.0.0.beta.19

According to David Chelimsky:

RSpec delegates redirect_to to Rails’ assert_template. In Ruby-1.9, we rely on Minitest instead
of Test::Unit, and its Assertions module is mixed in, and that module has a message method in
it. The let method defines a method, whose name is derived from the name passed to it: in this
case, message. That message method overrides the message method in Minitest::Assertions,
and thus, the error you see is created.

Here's a failing example:

require 'spec_helper'

describe MessagesController do
  let(:message) { mock_model(Message).as_null_object }

  describe "POST create" do
    it "redirects to the Messages index" do
      Message.stub(:new).and_return(message)

      post :create
      response.should redirect_to(:action => "index")
    end
  end
end

[dchelimsky]

I started a thread on the rspec-user's list about this: http://groups.google.com/group/rspec/browse_thread/thread/9f047fdb90599cc5

[dchelimsky]

I added a Gotchas page to the repo.

[dchelimsky]

I've got a tentative solution for this on a branch: http://github.com/rspec/rspec-rails/commit/86600313462638e7becc726e53f1bc67af108667

I'm not convinced this is the right way to go, but I can't think of a specific reason not to. Anybody else care to comment?

[dchelimsky]

Wrap T/U and/or MiniTest assertions in a separate scope from that of the
example.

• Closed by 46ab6bf.