How do I test a local variable inside a controller with Rspec?

Question

In my Dashboard#Index, I have this:

  def index        
    tagged_nodes = Node.includes(:user_tags).tagged_with(current_user.email)    
  end

How do I test this with RSpec?

I tried:

  expect(assigns(tagged_nodes)).to match Node.includes(:user_tags).tagged_with(u1.email)

But that gives me this error:

 NameError:
       undefined local variable or method `tagged_nodes' for #<RSpec::ExampleGroups::DashboardController::GETIndex:0x007fe4edd7f058>

Answer 1

You cannot (and should not) test local variables. However, you can and should test instance variables, which are the ones that start with @. For that you use the assigns helper, passing it the name of the instance variable as a symbol. If we want the value of the instance variable @tagged_nodes, we call assigns(:tagged_nodes) (note the :).

So if your controller method looks like this:

def index        
  @tagged_nodes = Node.includes(:user_tags).tagged_with(current_user.email)    
end

...you would access @tagged_nodes with assigns(:tagged_nodes):

expect(assigns(:tagged_nodes))
  .to match Node.includes(:user_tags).tagged_with(u1.email)