Question

I have a Discussion (polymorphic resource) that can belong to Project, Task and Subtask. I have troubles testing the following create action:

 26   def create               
 27     @discussion = @parent.discussions.build(params[:discussion])
 28     @discussion.user_id = current_user.id
 29     if @discussion.save    
 30       current_user.discussions.push(@discussion)
 31       redirect_to [@parent, @discussion], :notice => 'Discussion started' 
 32     else                   
 33       render 'new'         
 34       flash.now[:alert] = 'Unable to start discussion'
 35     end                    
 36   end

These are before filters that happen before create action (these find the necessary things)

 63   private
 64 
 65   def find_cached_parent_or_from_something_id
 66     @parent || find_parent_from_something_id # this does a bit of caching
 67   end
 68 
 69   def find_parent_from_something_id
 70     @parent = nil
 71     params.each do |name, value|
 72       if name =~ /(.+)_id$/
 73         @parent = name.humanize.constantize.find(value)
 74       end
 75     end
 76     @parent
 77   end
 78
 79   def find_project_from_parent_belonging_project
 80     @project = @parent.belonging_project
 81     unless current_user.projects.include?(@project)
 82       redirect_to projects_path
 83       flash[:alert] = msg_page_not_found
 84     end
 85   end

As you can see, I can find the parent and all the variables needed. Now this is how my RSpec controller test for the create action looks like: They all pass:

104         it "can create discussion on project using valid attributes" do                                                                   
105           lambda do
106             post :create, :project_id => project,         
107                           :discussion => valid_attributes
108             flash[:notice].should == 'Discussion started'
109           end.should change(Discussion, :count).by(1)                                                                                     
110         end
111   
112         it "can create discussion on task using valid attributes" do                                                                      
113           lambda do
114             post :create, :task_id => task,               
115                           :discussion => valid_attributes
116             flash[:notice].should == 'Discussion started'
117           end.should change(Discussion, :count).by(1)                                                                                     
118         end
119 
120         it "can create discussion on subtask using valid attributes" do                                                                   
121           lambda do
122             post :create, :subtask_id => subtask,         
123                           :discussion => valid_attributes
124             flash[:notice].should == 'Discussion started'
125           end.should change(Discussion, :count).by(1)                                                                                     
126         end

But, I’d prefer to test creation of discussion on all parents as DRY as possible, something along the lines of the next test.

104         ['project', 'task', 'subtask'].each do |parent|
105           it "can create discussion on #{parent} using valid attributes" do
106             lambda do      
107               post :create, :parent_id => parent,
108                             :discussion => valid_attributes 
109               flash[:notice].should == 'Discussion started'
110             end.should change(Discussion, :count).by(1)
111           end
112         end

How to write this test properly?

I am using FactoryGirl btw. This test above returns > NameError: uninitialized constant Parent

Also, if there is better way/practice of doing this, by all means, correct me 🙂

EDIT: I have solved the problem using the accepted answer below and have stumbled upon another one, very similar, that I again don’t know…

142           it "can access show action for discussion for #{parent}" do
143             get :show, :"#{parent}_id" => self.send(parent),
144                        :id => "disucussion_by_another_user_for_#{parent}"    
146             response.should be_successful   
147           end

This :id parameter is written wrong… Can you please help me write it properly? (this discussion_by_another_user_for_#{parent} are 3 different factories I defined…)

This is how my factories look like:

16   let!(:discussion_by_another_user_for_project) { FactoryGirl.create(:discussion,
 17                                                                      :user => another_user,
 18                                                                      :discussionable => project) }
 19   let!(:discussion_by_another_user_for_task) { FactoryGirl.create(:discussion,
 20                                                                      :user => another_user,
 21                                                                      :discussionable => task) }
 22   let!(:discussion_by_another_user_for_subtask) { FactoryGirl.create(:discussion,
 23                                                                      :user => another_user,
 24                                                                      :discussionable => subtask) }

Answer 1

I think you were almost there:

["project", "task", "subtask'].each do |parent|
  it "can create discussion on #{parent} using valid attributes" do                                                                      
    lambda do   
      post :create, :"#{parent}_id" => self.send(parent),               
                    :discussion => valid_attributes
      flash[:notice].should == 'Discussion started'
    end.should change(Discussion, :count).by(1)                                                                                     
  end
end

Hope this helps.

[EDIT] Your extra question: I am not quite sure how you believe handing down a mere string would actually create an object. You create an object with FactoryGirl as follows:

FactoryGirl.create(:factory_name)

So, if you take that into account, your test becomes:

it "can access show action for discussion for #{parent}" do
  discussion_by_another_user = FactoryGirl.create("discussion_by_another_user_for_#{parent}".to_sym)    
  get :show, :"#{parent}_id" => self.send(parent),
      :id => discussion_by_another_user.id
  response.should be_successful   
end

Of course, you could inline the parameter discussion_by_another_user, but I think this is a bit more readable. Hope this helps.

[EDIT] After clarified question: this is actually completely identical that what you asked before.
You build a string, but the string is actually a method you want to call, and as before, you
just write:

it "can access show action for discussion for #{parent}" do
  get :show, :"#{parent}_id" => self.send(parent),
             :id => self.send("discussion_by_another_user_for_#{parent}")
  response.should be_successful   
end

HTH