Respond with 404 when there is no matching FC class

lib/focused_controller.rb

@@ -2,3 +2,4 @@
 require 'focused_controller/route'
 require 'focused_controller/mixin'
 require 'focused_controller/route_mapper'
+require 'focused_controller/railtie' if defined?(Rails)

lib/focused_controller/railtie.rb

@@ -0,0 +1,13 @@
+module FocusedController
+  class Railtie < Rails::Railtie
+    if config.action_dispatch.rescue_responses
+      config.action_dispatch.rescue_responses['FocusedController::NotFound'] = :not_found
+      config.action_dispatch.rescue_templates['FocusedController::NotFound'] = 'unknown_action'
+    else
+      initializer 'focused_controller.not_found' do
+        ActionDispatch::ShowExceptions.rescue_responses['FocusedController::NotFound'] = :not_found
+        ActionDispatch::ShowExceptions.rescue_templates['FocusedController::NotFound'] = 'unknown_action'
+      end
+    end
+  end
+end

lib/focused_controller/route.rb

@@ -1,4 +1,6 @@
 module FocusedController
+  class NotFound < RuntimeError; end
+
   class Route
     attr_reader :name
 
@@ -7,9 +9,17 @@ def initialize(name)
     end
 
     def call(env)
-      name.constantize.call(env)
+      action_class.call(env)
     end
 
     alias to_s name
+
+    private
+
+    def action_class
+      name.constantize
+    rescue NameError => e
+      raise NotFound, e.to_s
+    end
   end
 end

test/acceptance/app_test.rb

@@ -66,7 +66,7 @@ def read_output(stream)
   # actually run the test.
   def start_server
     within_test_app do
-      IO.popen("bundle exec rails s -p #{FocusedController::Test.port} 2>&1") do |out|
+      IO.popen("rails s -p #{FocusedController::Test.port} 2>&1") do |out|
         start   = Time.now
         started = false
         output  = ""
@@ -130,6 +130,13 @@ def start_server
     end
   end
 
+  it 'renders a 404 error when the requested action is missing' do
+    start_server do
+      s.visit '/posts/missing'
+      s.status_code.must_equal 404
+    end
+  end
+
   it 'runs a functional test' do
     run_command "ruby -Itest test/functional/posts_controller_test.rb"
   end

test/app/config/routes.rb

@@ -1,6 +1,10 @@
 App::Application.routes.draw do
   focused_controller_routes do
-    resources :posts
+    resources :posts do
+      collection do
+        get :missing
+      end
+    end
   end
 
   # The priority is based upon order of creation: