Checking instance variables in a controller with RSpec

Question

For such a controller, where it creates several instance variables for use in the view, do you usually test that each one is correctly configured? It sounds like you want, but it also seems a bit complicated. What is the right approach?

class StaffsController < ApplicationController def index set_index_vars @all_staff = Staff.find_staff_for_business_all_inclusive(current_business_id) respond_to do |format| format.html { render :action => "index", :locals => { :all_staff => @all_staff, :all_services => @all_services, :new_vacation => @new_vacation } } end end def set_index_vars @days_of_week = days_of_week @first_day_of_week = DefaultsConfig.first_day_of_week @all_services = Service.services_for_business(current_business_id) @new_vacation = StaffVacation.new @has_hit_staff_limit = current_user_plan.has_hit_staff_limit? end end 

The code is also available at https://gist.github.com/1018190

Answer 1

If you are going to write a controller specification, then yes, be sure to check that instance variables are assigned. Most of the "trick" can come from dependencies on other models / libraries, so disable these method calls:

 # air code Staff.stub(:find_staff_for_business_all_inclusive) {array_of_staff} controller.stub(:days_of_week) {['Monday','Tuesday',....etc...]} DefaultsConfig.stub(:first_day_of_week) {"Monday"} Service.stub(:services_for_business).with(some_value_for_the_current_business_id).\ and_return(some_relevant_value) StaffVacation.stub(:new) {something_meaningful} controller.stub_chain(:current_user_plan,:has_hit_staff_limit?) {false} get :index assigns(:days_of_week).should == ['Monday','Tuesday',....etc...] # ...etc... 

Answer 2

I would split it like this: check that index is calling the correct method. Then check if this method works.

So something like

 describe StaffsController do describe "GET #index" do it "calls set_index_vars" do controller.should_receive(:set_index_vars) get :index end # and your usual tests ... end describe "#set_index_vars" do before(:each) do # stub out the code not from this controller controller.stub_chain(:current_user_plan, :has_hit_staff_limit?).and_return(false) .. etc .. controller.set_index_vars end it { assigns(:days_of_week).should == controller.days_of_week } it { assigns(:has_hit_staff_limit).should be_false # etc .. end end 

Hope this helps.

Answer 3

As long as you have good coverage around your method, you can verify that your method is being called at the right time, with the correct values, etc. Something like:

 describe StaffsController do describe "GET #index" do it "should call set_index_vars" do controller.should_receive(:set_index_vars) get :index end end describe "#set_index_vars" do it "should assign instance variables with correct values" do # or wtv this is supposed to do get :index assigns(:days_of_week).should == controller.days_of_week # etc .. end end end