make sure failed builds exit with correct status code

features/builder.feature

@@ -17,11 +17,17 @@ Feature: Builder
     Then "images/Read me (example).txt" should exist at "test-app"
     Then "images/Child folder/regular_file(example).txt" should exist at "test-app"
     Then ".htaccess" should exist at "test-app"
+    Then the last exit code should be "0"
     
   Scenario: Build glob
     Given a built app at "glob-app" with flags "--glob '*.css'"
     Then "stylesheets/site.css" should exist at "glob-app" and include "html"
     Then "index.html" should not exist at "glob-app"
+    Then the last exit code should be "0"
+  
+  Scenario: Build with errors
+    Given a built app at "build-with-errors-app"
+    Then the last exit code should be "1"
     
   # Scenario: Force relative assets
   #   Given a built app at "relative-app" with flags "--relative"

fixtures/build-with-errors-app/config.rb

@@ -0,0 +1 @@
+set :layout, false

fixtures/build-with-errors-app/source/index.html.erb

@@ -0,0 +1 @@
+<%= error_error_error %>

lib/middleman/builder.rb

@@ -42,11 +42,13 @@ module Middleman
           destination, request_path = ::Middleman::Builder.shared_instance.reroute_builder(destination, request_path)
 
           response = ::Middleman::Builder.shared_rack.get(request_path.gsub(/\s/, "%20"))
-          create_file(destination, response.body, config) if response.status == 200
+
+          create_file(destination, response.body, config)
 
           destination
         rescue
           say_status :error, destination, :red
+          abort
         end
       end
     end

lib/middleman/core_extensions/show_exceptions.rb

@@ -3,7 +3,7 @@ require 'rack/showexceptions'
 module Middleman::CoreExtensions::ShowExceptions
   class << self
     def registered(app)
-      app.after_configuration do
+      app.configure :development do
         if show_exceptions
           use ::Middleman::CoreExtensions::ShowExceptions::Middleware
         end

lib/middleman/step_definitions/builder_steps.rb

@@ -42,4 +42,9 @@ end
 Then /^"([^\"]*)" should not exist at "([^\"]*)"$/ do |target_file, path|
   target = File.join(PROJECT_ROOT_PATH, "fixtures", path, "build", target_file)
   File.exists?(target).should be_false
-end
+end
+
+Then /^the last exit code should be "([^\"]*)"$/ do |exit_code|
+  exit_code = exit_code.to_i
+  $?.exitstatus.should == exit_code
+end