Fix that failed tests should exit with a nonzero error code.

Partially reverts 14c89e7285d4e7cd40a542fbc31d9345f60c3aa4.

Hat tip to @tenderlove for paring down the TestTask!

railties/lib/rails/test_unit/sub_test_task.rb

@@ -1,36 +1,8 @@
 module Rails
-  # Don't abort when tests fail; move on the next test task.
   # Silence the default description to cut down on `rake -T` noise.
   class SubTestTask < Rake::TestTask
-    # Create the tasks defined by this task lib.
-    def define
-      lib_path = @libs.join(File::PATH_SEPARATOR)
-      task @name do
-        run_code = ''
-        RakeFileUtils.verbose(@verbose) do
-          run_code =
-            case @loader
-            when :direct
-              "-e 'ARGV.each{|f| load f}'"
-            when :testrb
-              "-S testrb #{fix}"
-            when :rake
-              rake_loader
-            end
-          @ruby_opts.unshift( "-I\"#{lib_path}\"" )
-          @ruby_opts.unshift( "-w" ) if @warning
-
-          begin
-            ruby @ruby_opts.join(" ") +
-              " \"#{run_code}\" " +
-              file_list.collect { |fn| "\"#{fn}\"" }.join(' ') +
-              " #{option_list}"
-          rescue => error
-            warn "Error running #{name}: #{error.inspect}"
-          end
-        end
-      end
-      self
+    def desc(string)
+      # Ignore the description.
     end
   end
 end

railties/lib/rails/test_unit/testing.rake

@@ -55,7 +55,21 @@ namespace :test do
     # Placeholder task for other Railtie and plugins to enhance. See Active Record for an example.
   end
 
-  task :run => %w(test:units test:functionals test:integration)
+  task :run do
+    errors = %w(test:units test:functionals test:integration).collect do |task|
+      begin
+        Rake::Task[task].invoke
+        nil
+      rescue => e
+        { :task => task, :exception => e }
+      end
+    end.compact
+
+    if errors.any?
+      puts errors.map { |e| "Errors running #{e[:task]}! #{e[:exception].inspect}" }.join("\n")
+      abort
+    end
+  end
 
   Rake::TestTask.new(:recent => "test:prepare") do |t|
     since = TEST_CHANGES_SINCE