How can I test Rails rescue_from?

Question

Rails 3 seems is ignoring my rescue_from handler so I cannot test my redirect below.

class ApplicationController < ActionController::Base

  rescue_from ActionController::RoutingError, :with => :rescue_404 

  def rescue_404
    flash[:notice] = "Error 404. The url <i>'#{env["vidibus-routing_error.request_uri"]}'</i> does not exist on this website."
    redirect_to root_path
  end
end

In both functional and integration tests, this rescue_from is ignored, and the error is raised:

ActionController::RoutingError: No route matches "/non_existent_url"
    test/integration/custom_404_test.rb:5:in `test_404'

How can I make sure this is properly 'caught' in a test?

Answer 1

Rails 3 handles ActionController::RoutingError in middleware, so ApplicationController::rescue_from doesn't see the exception. The Rails core team recommends using a catch-all route at the bottom of routes.rb (GitHub issue) until they decide on a fix.

One option is to use a catch-all route to handle routing errors then manually raise an exception to hit rescue_from (code from my blog post about this issue):

# routes.rb
match "*path", :to => "application#routing_error"

# application_controller.rb
rescue_from ActionController::RoutingError, :with => :render_not_found

def routing_error
  raise ActionController::RoutingError.new(params[:path])
end

def render_not_found
  render :template => "misc/404"
end