ruby - How do I set HTTP_REFERER when testing in Rails?

Question

I'm trying to test a controller and I got this error. I understand the error, but don't know how to fix it.

test: on CREATE to :user with completely invalid email should respond with 
  redirect
(UsersControllerTest):ActionController::RedirectBackError: 
  No HTTP_REFERER was set in the request to this action, 
  so redirect_to :back could not be called successfully. 
If this is a test, make sure to specify request.env["HTTP_REFERER"].

Specify it where? I tried this:

setup { post :create, { :user => { :email => 'invalid@abc' } }, 
  { 'referer' => '/sessions/new' } }

But got the same error.

Specify it with what, exactly? I guess the URI of the view I want it to go back to:

'/sessions/new'

Is that what they mean?

---

OK, so it turns out they mean do this:

setup do
  @request.env['HTTP_REFERER'] = 'http://localhost:3000/sessions/new'
  post :create, { :user => { :email => 'invalid@abc' } }, {}
end

Can someone tell me where that's documented? I'd like to read up on the context of that information.

What if the domain is not "localhost:3000"? What if it's "localhost:3001" or something? Any way to anticipate that?

Why doesn't this work:

setup { post :create, { :user => { :email => 'invalid@abc' } }, 
  { 'referer' => '/sessions/new' } }

The Rails docs specifically say that's how you set the headers.

Answer 1

Their recommendation translates to the following:

setup do
  @request.env['HTTP_REFERER'] = 'http://test.com/sessions/new'
  post :create, { :user => { :email => 'invalid@abc' } }
end