test some of the rc specification

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -327,6 +327,10 @@ def prepare!
         argv
       end
 
+      def self.default_rc_file
+        File.join(File.expand_path('~'), '.railsrc')
+      end
+
       private
 
         def handle_version_request!(argument)
@@ -353,7 +357,7 @@ def railsrc
           if (customrc = argv.index{ |x| x.include?("--rc=") })
             File.expand_path(argv.delete_at(customrc).gsub(/--rc=/, ""))
           else
-            File.join(File.expand_path("~"), '.railsrc')
+            self.class.default_rc_file
           end
         end
 

railties/test/generators/argv_scrubber_test.rb

 require 'active_support/test_case'
 require 'active_support/testing/autorun'
 require 'rails/generators/rails/app/app_generator'
+require 'tempfile'
 
 module Rails
   module Generators
@@ -14,7 +15,7 @@ def test_version
             define_method(:puts) { |str| output = str }
             define_method(:exit) { |code| exit_code = code }
           })
-          scrubber.prepare
+          scrubber.prepare!
           assert_equal "Rails #{Rails::VERSION::STRING}", output
           assert_equal 0, exit_code
         end
@@ -22,15 +23,54 @@ def test_version
 
       def test_prepare_returns_args
         scrubber = ARGVScrubber.new ['hi mom']
-        args = scrubber.prepare
+        args = scrubber.prepare!
         assert_equal '--help', args.first
       end
 
       def test_no_mutations
         scrubber = ARGVScrubber.new ['hi mom'].freeze
-        args = scrubber.prepare
+        args = scrubber.prepare!
         assert_equal '--help', args.first
       end
+
+      def test_new_command_no_rc
+        scrubber = Class.new(ARGVScrubber) {
+          def self.default_rc_file
+            File.join(Dir.tmpdir, 'whatever')
+          end
+        }.new ['new']
+        args = scrubber.prepare!
+        assert_nil args.first
+        assert_equal [], args
+      end
+
+      def test_new_homedir_rc
+        file = Tempfile.new 'myrcfile'
+        file.puts '--hello-world'
+        file.flush
+
+        message = nil
+        scrubber = Class.new(ARGVScrubber) {
+          define_singleton_method(:default_rc_file) do
+            file.path
+          end
+          define_method(:puts) { |msg| message = msg }
+        }.new ['new']
+        args = scrubber.prepare!
+        assert_nil args.first
+        assert_equal [nil, '--hello-world'], args
+        assert_match 'hello-world', message
+        assert_match file.path, message
+      ensure
+        file.close
+        file.unlink
+      end
+
+      def test_no_rc
+        scrubber = ARGVScrubber.new ['new', '--no-rc']
+        args = scrubber.prepare!
+        assert_equal [], args
+      end
     end
   end
 end