Why is this view template expected?

问题

I have a controller method to authenticate a user who has received a link with a token (see method at the bottom). I have an integration test:

def test
  get login_path('invalid token')     // Login_path routes to the controller method below.
  assert flash[:danger]
  assert_redirected_to root_path
end

This test produces the following error (referring to get login_path('invalid token')):

ActionView::MissingTemplate: Missing template invitations/login, application/login with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :coffee, :jbuilder]}. 

The view invitiations/login indeed doesn't exist. However, such a view should never be needed given the controller method below (it always either redirects to the root_path or renders profiles/show). What could be causing this error?

The controller method:

def login
  inv = Invitation.where('email = ?', params[:email])
  if inv
    inv.each do |person|
      if person.authenticated?(:invitation, params[:id])
        @organization = person.organization
        unless @organization.nil?
          render 'profiles/show' and return
        else
          flash[:danger] = "Error"
          redirect_to root_path and return
        end
      end
      flash[:danger] = "Invalid link"
      redirect_to root_path
    end
  else
    flash[:danger] = "Invalid link"
    redirect_to root_path
  end
end

P.S. The test used to pass, i.e. until I rewrote the controller method to accommodate for multiple inv's (see Retrieve multiple records with find_by method).

回答1:

You use if inv - this will still return true if no invitations with matching email exist, since inv is an ActiveRecord query object. But then the each does nothing, i.e. does not redirect or render explicitly. Default render will be invoked and expect a template to exist.

Using if inv.present? will fix this.

(Also, you might want to make sure the inv collection only contains one result. Redirecting or rendering multiple times in the same request will result in an error.)

来源：https://stackoverflow.com/questions/34474335/why-is-this-view-template-expected