diff --git a/actionpack/lib/action_controller/test_process.rb b/actionpack/lib/action_controller/test_process.rb
index dbaec00..becfa21 100644
--- a/actionpack/lib/action_controller/test_process.rb
+++ b/actionpack/lib/action_controller/test_process.rb
@@ -485,7 +485,17 @@ module ActionController #:nodoc:
 
     def html_document
       xml = @response.content_type =~ /xml$/
-      @html_document ||= HTML::Document.new(@response.body, false, xml)
+
+      text = if @response.body.respond_to?(:call)
+        out = StringIO.new
+        @response.body.call(out, out)
+        out.rewind
+        out.read
+      else
+        @response.body
+      end
+
+      @html_document ||= HTML::Document.new(text, false, xml)
     end
 
     def find_tag(conditions)
diff --git a/actionpack/test/controller/render_test.rb b/actionpack/test/controller/render_test.rb
index a529315..3a98856 100644
--- a/actionpack/test/controller/render_test.rb
+++ b/actionpack/test/controller/render_test.rb
@@ -231,6 +231,12 @@ class TestController < ActionController::Base
     render :text => false
   end
 
+  def render_text_with_proc
+    render :text => Proc.new{ |resp, out|
+      1.upto(10){ |i| out.write "<element>#{i}</element>" }
+    }
+  end
+
   def render_nothing_with_appendix
     render :text => "appended"
   end
@@ -939,6 +945,12 @@ class RenderTest < ActionController::TestCase
     get :render_text_with_false
     assert_equal 'false', @response.body
   end
+  
+  def test_render_text_with_proc
+    get :render_text_with_proc
+    assert_response :success
+    assert_select "element", 10
+  end
 
   def test_render_nothing_with_appendix
     get :render_nothing_with_appendix