[rspec-users] Could not find shared example group named "an admin is logged in"

David Chelimsky dchelimsky at gmail.com
Fri Oct 8 10:21:12 EDT 2010


On Oct 8, 2010, at 8:20 AM, Tim Gremore wrote:

> On Thu, Oct 7, 2010 at 8:25 PM, David Chelimsky <dchelimsky at gmail.com> wrote:
> On Oct 7, 2010, at 4:36 PM, Tim Gremore wrote:
> 
>> I'm stuck! Not sure what I'm missing but I'm struggling to get a shared example group working with my controller specs.  Here is a piece of the backtrace:
>> 
>> /Users/20217633/.rvm/gems/ruby-1.9.2-p0 at rails3/gems/rspec-core-2.0.0.rc/lib/rspec/core/example_group.rb:68:in `it_should_behave_like': Could not find shared example group named "an admin is logged in" (RuntimeError)
>> 	from /Users/20217633/apps/curriculum/spec/controllers/users_controller_spec.rb:5:in `block in <top (required)>'
>> 	from /Users/20217633/.rvm/gems/ruby-1.9.2-p0 at rails3/gems/rspec-core-2.0.0.rc/lib/rspec/core/example_group.rb:132:in `module_eval'
>> 	from /Users/20217633/.rvm/gems/ruby-1.9.2-p0 at rails3/gems/rspec-core-2.0.0.rc/lib/rspec/core/example_group.rb:132:in `subclass'
>> 	from /Users/20217633/.rvm/gems/ruby-1.9.2-p0 at rails3/gems/rspec-core-2.0.0.rc/lib/rspec/core/example_group.rb:119:in `describe'
>> 	from /Users/20217633/.rvm/gems/ruby-1.9.2-p0 at rails3/gems/rspec-core-2.0.0.rc/lib/rspec/core/extensions/object.rb:7:in `describe'
>> 	from /Users/20217633/apps/curriculum/spec/controllers/users_controller_spec.rb:3:in `<top (required)>'
>> 
>> I'm using the following:
>> 
>> rails 3.0
>> rspec-rails 2.0.0.rc (and friends)
>> cucumber-rails 0.3.2
>> factory_girl_rails 1.0
>> 
>> And the following for shared examples:
>> 
>> module ExampleGroupMethods
>> 
>>   describe "an admin is logged in", :shared => true do
>>     before(:each) do
>>       controller.stubs(:logged_in? => true)
>>       controller.stubs(:current_user => Factory.create(:admin))
>>     end
>>   end
>> 
>>   describe "a supporter is logged in", :shared => true do
>>     before(:each) do
>>       controller.stubs(:logged_in? => true)
>>       controller.stubs(:current_user => Factory.create(:supporter))
>>     end
>>   end
>> 
>>   describe "a manager is logged in", :shared => true do
>>     before(:each) do
>>       controller.stubs(:logged_in? => true)
>>       controller.stubs(:current_user => Factory.create(:manager))
>>     end
>>   end
>>   
>> end
>> 
>> And the follow controller spec:
>> 
>> describe UsersController do
>>   
>>   it_should_behave_like "an admin is logged in"
>>   
>>   describe "handling /users" do
>> 
>>     before do
>>       @user = mock_model(User)
>>     end
>>     
>>     def do_get
>>       get :index
>>     end
>>     
>>     it "should assign users to the view" do
>>       User.should_receive(:all).with(:order => "last_name, first_name").and_return([ @user ])
>>       do_get
>>     end
>>     
>>   end
>> 
>> end
>> 
>> And finally this spec_helper:
>> 
>> # This file is copied to spec/ when you run 'rails generate rspec:install'
>> ENV["RAILS_ENV"] ||= 'test'
>> require File.expand_path("../../config/environment", __FILE__)
>> require 'rspec/rails'
>> 
>> # Requires supporting ruby files with custom matchers and macros, etc,
>> # in spec/support/ and its subdirectories.
>> Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
>> 
>> RSpec.configure do |config|
>>   # == Mock Framework
>>   #
>>   # If you prefer to use mocha, flexmock or RR, uncomment the appropriate line:
>>   #
>>   # config.mock_with :mocha
>>   # config.mock_with :flexmock
>>   # config.mock_with :rr
>>   config.mock_with :rspec
>> 
>>   # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
>>   # config.fixture_path = "#{::Rails.root}/spec/fixtures"
>> 
>>   # If you're not using ActiveRecord, or you'd prefer not to run each of your
>>   # examples within a transaction, remove the following line or assign false
>>   # instead of true.
>>   config.use_transactional_fixtures = true
>>   
>>   # see http://asciicasts.com/episodes/157-rspec-matchers-macros
>>   config.include(ControllerMacros, :type => :controller)
>>   
>>   # see http://pastie.org/870928
>>   config.include(ExampleGroupMethods, :type => :controller)
>> end
>> 
>> Anyone have a suggestion?  Thanks in advance
> 
> Shared examples have changed significantly in rspec-2. See http://github.com/rspec/rspec-core/blob/master/features/example_groups/shared_example_group.feature to get a feel for how they work now.
> 
> The first thing is that :shared = true no longer works. You need to use shared_examples_for. The other big change is that it_should_behave_like creates a nested group, so if you do this:
> 
> shared_examples_for "foo" do
>   it "does something" do
>   end
> end
> 
> describe "something" do
>   it_behaves_like "foo" # it_behaves_like is an alias for it_should_behave_like
> end
> 
> That's the same as doing this:
> 
> describe "something" do
>   context "behaves like foo" do
>     it "does something" do
>     end
>   end
> end
> 
> This is a good thing, because it prevents the context of the shared group from polluting the including group's scope, which can lead (and has led) to a lot of confusion.
> 
> Now in your case, you're using the shared group as a means of sharing before blocks. While that works, it's the opposite of the intent of shared groups, which is that the enclosing group should provide the context for the shared group. What you _can_ do, however, to maintain the structure you have, is to pass a block to it_should_behave_like, so your example change from this:
> 
> # rspec-1
> describe UsersController do
>   it_should_behave_like "an admin is logged in"
>   describe "handling /users" do
>     before do
>       @user = mock_model(User)
>     end
>     
>     def do_get
>       get :index
>     end
>     
>     it "should assign users to the view" do
>       User.should_receive(:all).with(:order => "last_name, first_name").and_return([ @user ])
>       do_get
>     end
>   end
> end
> 
> to this:
> 
> #rspec-2
> describe UsersController do
>   it_should_behave_like "an admin is logged in" do
>     describe "handling /users" do
>       before do
>         @user = mock_model(User)
>       end
>       
>       def do_get
>         get :index
>       end
>       
>       it "should assign users to the view" do
>         User.should_receive(:all).with(:order => "last_name, first_name").and_return([ @user ])
>         do_get
>       end
>     end
>   end
> end
> 
> HTH,
> David

> Thanks much Justin and David - very helpful.  David, you explained that I could accomplish my goal by sending a block to it_should_behave_like, even though that is not its intended purpose.  Is there a cleaner way to accomplish my goal (spec'ing controller authentication and authorization)?

Not sure if I was clear. I didn't mean to imply that passing a block a bad thing. Quite the contrary. Passing blocks is a big part of what makes shared groups in rspec-2 better than rspec-1 for their intended purpose:

  to share examples for a conceptual (duck) type or a module, with the including group providing concrete context.

What you're doing is the opposite - providing context using a shared group. 

Does that make sense? This is not to say that this is wrong, or evil. It's just the reverse of the intent.

Take a close look at this scenario: http://github.com/rspec/rspec-core/blob/c5e6bc031404762edcda7789ecc04c6d340c8ef6/features/example_groups/shared_example_group.feature#L11. It demonstrates shared examples for a collection, applied to two different types, with the context provided by the "describe Array" group (which provides an instance of Array as the implicit subject) and the "describe Set" group (which provides a Set).

Let me know if you have any questions.

Cheers,
David

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