From 316dca039e72cbed40a563ea123d82504b3b2484 Mon Sep 17 00:00:00 2001
From: Norman Clarke <norman@randomba.org>
Date: Tue, 14 Oct 2008 14:29:43 -0300
Subject: [PATCH] Added ActionView::Helpers::CaptureHelper#content_exists? to check for named content blocks set using content_for

---
 .../lib/action_view/helpers/capture_helper.rb      |   13 +++++++++
 actionpack/test/template/capture_helper_test.rb    |   28 ++++++++++++++++++++
 2 files changed, 41 insertions(+), 0 deletions(-)
 create mode 100644 actionpack/test/template/capture_helper_test.rb

diff --git a/actionpack/lib/action_view/helpers/capture_helper.rb b/actionpack/lib/action_view/helpers/capture_helper.rb
index e86ca27..b5d8462 100644
--- a/actionpack/lib/action_view/helpers/capture_helper.rb
+++ b/actionpack/lib/action_view/helpers/capture_helper.rb
@@ -122,6 +122,19 @@ module ActionView
         nil
       end
 
+      # Checks to see if named block of content has been set using
+      # <tt>+content_for+</tt>. This can be used to conditionally display
+      # default content for a named block if none has been set. For example:
+      #
+      #   <% if content_exists? :navigation %>
+      #     yield :navigation
+      #   <% else %>
+      #     <%= render :partial => "default_navigation"
+      #   <% end %>
+      def content_exists?(name)
+        instance_variable_defined?("@content_for_#{name.to_s}")
+      end
+
       # Use an alternate output buffer for the duration of the block.
       # Defaults to a new empty string.
       def with_output_buffer(buf = '') #:nodoc:
diff --git a/actionpack/test/template/capture_helper_test.rb b/actionpack/test/template/capture_helper_test.rb
new file mode 100644
index 0000000..f655634
--- /dev/null
+++ b/actionpack/test/template/capture_helper_test.rb
@@ -0,0 +1,28 @@
+require 'abstract_unit'
+
+class CaptureHelperTest < ActionView::TestCase
+
+  tests ActionView::Helpers::CaptureHelper
+
+  def test_capture
+    captured = capture do
+      "hello world"
+    end
+    assert_equal "hello world", captured
+  end
+
+  def test_content_for
+    content_for :my_test do
+      "hello world"
+    end
+    assert_equal "hello world", @content_for_my_test
+  end
+
+  def test_content_exists
+    content_for :my_test do
+      "hello world"
+    end
+    assert content_exists?(:my_test)
+  end
+
+end
\ No newline at end of file
-- 
1.6.1