new reporting method Kernel#quietly

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *Rails 3.1.0 (unreleased)*
 
+* New reporting method Kernel#quietly. [fxn]
+
 * Add String#inquiry as a convenience method for turning a string into a StringInquirer object [DHH]
 
 * Add Object#in? to test if an object is included in another object [Prem Sichanugrist, Brian Morearty, John Reitano]

activesupport/lib/active_support/core_ext/kernel/reporting.rb

@@ -62,7 +62,7 @@ module Kernel
   
   # Captures the given stream and returns it:
   #
-  #   stream = capture(:stdout){ puts "Cool" }
+  #   stream = capture(:stdout) { puts "Cool" }
   #   stream # => "Cool\n"
   #
   def capture(stream)
@@ -78,4 +78,16 @@ module Kernel
     result
   end
   alias :silence :capture
+
+  # Silences both STDOUT and STDERR, even for subprocesses.
+  #
+  #   quietly { system 'bundle install' }
+  #
+  def quietly
+    silence_stream(STDOUT) do
+      silence_stream(STDERR) do
+        yield
+      end
+    end
+  end
 end

railties/guides/source/active_support_core_extensions.textile

@@ -417,6 +417,14 @@ silence_stream(STDOUT) do
 end
 </ruby>
 
+The +quietly+ method addresses the common use case where you want to silence STDOUT and STDERR, even in subprocesses:
+
+<ruby>
+quietly { system 'bundle install' }
+</ruby>
+
+For example, the railties test suite uses that one in a few places to prevent command messages from being echoed intermixed with the progress status.
+
 Silencing exceptions is also possible with +suppress+. This method receives an arbitrary number of exception classes. If an exception is raised during the execution of the block and is +kind_of?+ any of the arguments, +suppress+ captures it and returns silently. Otherwise the exception is reraised:
 
 <ruby>

railties/test/generators/app_generator_test.rb

@@ -66,7 +66,7 @@ class AppGeneratorTest < Rails::Generators::TestCase
   end
 
   def test_application_new_exits_with_non_zero_code_on_invalid_application_name
-    silence_stderr { `rails new test` }
+    quietly { system 'rails new test' }
     assert_equal false, $?.success?
   end
 

railties/test/generators/plugin_new_generator_test.rb

@@ -122,14 +122,14 @@ class PluginNewGeneratorTest < Rails::Generators::TestCase
   def test_ensure_that_tests_work
     run_generator
     FileUtils.cd destination_root
-    `bundle install` # use backticks to silence stdout
+    quietly { system 'bundle install' }
     assert_match(/1 tests, 1 assertions, 0 failures, 0 errors/, `bundle exec rake test`)
   end
 
   def test_ensure_that_tests_works_in_full_mode
     run_generator [destination_root, "--full", "--skip_active_record"]
     FileUtils.cd destination_root
-    `bundle install` # use backticks to silence stdout
+    quietly { system 'bundle install' }
     assert_match(/1 tests, 1 assertions, 0 failures, 0 errors/, `bundle exec rake test`)
   end