TDD with RSpec and Rails: testing controller actions with no view - ruby-on-rails-3

Question

As I continue to learn my way around TDD with RSpec 2 and Rails 3.1, I can't seem to find a solution to this problem.
I have a Users controller with a new and create action. In my UsersController spec, I have
users_controller_spec.rb
describe "POST 'create'" do
before(:each) do
#attr = Factory.attributes_for(:user)
end
it "should assign an #user variable" do
post :create, :user => #attr
assigns[:user].should_not be_nil
assigns[:user].should be_kind_of(User)
end
end
and in my UsersController,
users_controller.rb
def create
#user = User.new(params[:user])
end
This spec is failing with
1) UsersController POST 'create' should assign an #user variable
Failure/Error: post :create, :user => #attr
ActionView::MissingTemplate:
I can continue to implement application code to get this test to pass, but I feel like this test should be passing as it is.
Any suggestions?

Answer 1

Your create method needs to do something. Either render a template or redirect. Since you're not telling it to redirect it's assuming that you want it to render a template but when it can't find a create.html.erb file it throws an error.
You're best bet is to do either this:
def create
#user = User.new(params[:user])
redirect_to root_url
end
or this:
def create
#user = User.new(params[:user])
render :nothing => true
end

Answer 2

To test rendering nothing you'll want:
expect(response).to render_template(nil)

Answer 3

I've come across this recently myself. It seems one possibility would be to rescue the error in your test.
it "should assign an #user variable" do
begin
post :create, :user => #attr
rescue ActionView::MissingTemplate
# This is okay because(/as long as) we test the render/redirect
# in a separate spec where we don't rescue this exception.
end
assigns[:user].should_not be_nil
assigns[:user].should be_kind_of(User)
end
I don't know how "correct" this solution is. On one hand, it definitely emphasizes the "testing one thing at a time" mentality, on the other, it seems kind of ugly.
Edit
I suppose you could make some nice wrappers in your spec helper, something like
def post?(action, params = {})
post action, params
rescue ActionView::MissingTemplate
end