Move capture to Kernel. [#5641 state:resolved]

2 files changed, 24 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/kernel/reporting.rb b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
index 5105c40e4d..37a827123a 100644
--- a/activesupport/lib/active_support/core_ext/kernel/reporting.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
@@ -59,4 +59,23 @@ module Kernel
       raise unless exception_classes.any? { |cls| e.kind_of?(cls) }
     end
   end
+  
+  # Captures the given stream and returns it:
+  #
+  #   stream = capture(:stdout){ puts "Cool" }
+  #   stream # => "Cool\n"
+  #
+  def capture(stream)
+    begin
+      stream = stream.to_s
+      eval "$#{stream} = StringIO.new"
+      yield
+      result = eval("$#{stream}").string
+    ensure
+      eval("$#{stream} = #{stream.upcase}")
+    end
+
+    result
+  end
+  alias :silence :capture
 end
diff --git a/activesupport/test/core_ext/kernel_test.rb b/activesupport/test/core_ext/kernel_test.rb
index 904d56a87e..ede9b0a6aa 100644
--- a/activesupport/test/core_ext/kernel_test.rb
+++ b/activesupport/test/core_ext/kernel_test.rb
@@ -52,6 +52,11 @@ class KernelTest < Test::Unit::TestCase
     class << o; @x = 1; end
     assert_equal 1, o.class_eval { @x }
   end
+  
+  def test_capture
+    assert_equal 'STDERR', capture(:stderr) {$stderr.print 'STDERR'}
+    assert_equal 'STDOUT', capture(:stdout) {print 'STDOUT'}
+  end
 end
 
 class KernelSuppressTest < Test::Unit::TestCase