6 files changed, 35 insertions, 8 deletions
diff --git a/railties/lib/rails/generators/testing/assertions.rb b/railties/lib/rails/generators/testing/assertions.rb
index 17af6eddfa..76758df86d 100644
--- a/railties/lib/rails/generators/testing/assertions.rb
+++ b/railties/lib/rails/generators/testing/assertions.rb
@@ -1,5 +1,3 @@
-require 'shellwords'
-
 module Rails
   module Generators
     module Testing
diff --git a/railties/lib/rails/generators/testing/behaviour.rb b/railties/lib/rails/generators/testing/behaviour.rb
index c9700e1cd7..94b5e52224 100644
--- a/railties/lib/rails/generators/testing/behaviour.rb
+++ b/railties/lib/rails/generators/testing/behaviour.rb
@@ -92,7 +92,8 @@ module Rails
             cd current_path
           end
 
-          def prepare_destination # :nodoc:
+          # Clears all files and directories in destination.
+          def prepare_destination
             rm_rf(destination_root)
             mkdir_p(destination_root)
           end
diff --git a/railties/lib/rails/mailers_controller.rb b/railties/lib/rails/mailers_controller.rb
index 38004fe99a..6143cf2dd9 100644
--- a/railties/lib/rails/mailers_controller.rb
+++ b/railties/lib/rails/mailers_controller.rb
@@ -31,7 +31,7 @@ class Rails::MailersController < Rails::ApplicationController # :nodoc:
             raise AbstractController::ActionNotFound, "Email part '#{part_type}' not found in #{@preview.name}##{@email_action}"
           end
         else
-          @part = find_preferred_part(request.format, Mime::Type[:HTML], Mime::Type[:TEXT])
+          @part = find_preferred_part(request.format, Mime[:html], Mime[:text])
           render action: 'email', layout: false, formats: %w[html]
         end
       else
diff --git a/railties/lib/rails/templates/rails/mailers/email.html.erb b/railties/lib/rails/templates/rails/mailers/email.html.erb
index cf95cd8ad0..fed96fbc85 100644
--- a/railties/lib/rails/templates/rails/mailers/email.html.erb
+++ b/railties/lib/rails/templates/rails/mailers/email.html.erb
@@ -94,9 +94,9 @@
 
     <% if @email.multipart? %>
       <dd>
-        <select onchange="document.getElementsByName('messageBody')[0].src=this.options[this.selectedIndex].value;">
-          <option <%= request.format == Mime::Type[:HTML] ? 'selected' : '' %> value="?part=text%2Fhtml">View as HTML email</option>
-          <option <%= request.format == Mime::Type[:TEXT] ? 'selected' : '' %> value="?part=text%2Fplain">View as plain-text email</option>
+        <select onchange="formatChanged(this);">
+          <option <%= request.format == Mime[:html] ? 'selected' : '' %> value="?part=text%2Fhtml">View as HTML email</option>
+          <option <%= request.format == Mime[:text] ? 'selected' : '' %> value="?part=text%2Fplain">View as plain-text email</option>
         </select>
       </dd>
     <% end %>
@@ -112,5 +112,19 @@
   </p>
 <% end %>
 
+<script>
+  function formatChanged(form) {
+    var part_name = form.options[form.selectedIndex].value
+    var iframe =document.getElementsByName('messageBody')[0];
+    iframe.contentWindow.location.replace(part_name);
+
+    if (history.replaceState) {
+      var url    = location.pathname.replace(/\.(txt|html)$/, '');
+      var format = /html/.test(part_name) ? '.html' : '.txt';
+      window.history.replaceState({}, '', url + format);
+    }
+  }
+</script>
+
 </body>
 </html>
diff --git a/railties/lib/rails/test_unit/minitest_plugin.rb b/railties/lib/rails/test_unit/minitest_plugin.rb
index 3a0a58df88..d1ba35a5ec 100644
--- a/railties/lib/rails/test_unit/minitest_plugin.rb
+++ b/railties/lib/rails/test_unit/minitest_plugin.rb
@@ -3,6 +3,16 @@ require "rails/test_unit/reporter"
 require "rails/test_unit/test_requirer"
 
 module Minitest
+  mattr_accessor(:hide_aggregated_results) { false }
+
+  module AggregatedResultSuppresion
+    def aggregated_results
+      super unless Minitest.hide_aggregated_results
+    end
+  end
+
+  SummaryReporter.prepend AggregatedResultSuppresion
+
   def self.plugin_rails_options(opts, options)
     opts.separator ""
     opts.separator "Usage: bin/rails test [options] [files or directories]"
@@ -38,6 +48,7 @@ module Minitest
       options[:fail_fast] = true
     end
 
+    options[:output_inline] = true
     options[:patterns] = opts.order!
   end
 
@@ -63,6 +74,9 @@ module Minitest
       Minitest.backtrace_filter = ::Rails.backtrace_cleaner if ::Rails.respond_to?(:backtrace_cleaner)
     end
 
+    # Disable the extra failure output after a run, unless output is deferred.
+    self.hide_aggregated_results = options[:output_inline]
+
     self.reporter << ::Rails::TestUnitReporter.new(options[:io], options)
   end
 
diff --git a/railties/lib/rails/test_unit/reporter.rb b/railties/lib/rails/test_unit/reporter.rb
index 8f1116b6af..e1fe92a11b 100644
--- a/railties/lib/rails/test_unit/reporter.rb
+++ b/railties/lib/rails/test_unit/reporter.rb
@@ -49,7 +49,7 @@ module Rails
 
     private
       def output_inline?
-        options.fetch(:output_inline, true)
+        options[:output_inline]
       end
 
       def fail_fast?