diff --git a/ChangeLog b/ChangeLog
index 405ef3a7ad..91f948f504 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sun Jun 29 17:41:42 2008  Kouhei Sutou  <kou@cozmixng.org>
+
+	* lib/rss/maker/base.rb (RSS::Maker::RSSBase#to_feed): raise
+	exception not return nil if RSS::Maker.make can't get required
+	information.
+	* test/rss/rss-assertions.rb: follow the above change.
+
 Sun Jun 29 17:37:23 2008  Kouhei Sutou  <kou@cozmixng.org>
 
 	* lib/rss/maker/base.rb (RSS::Maker::RSSBase#make): require block.
diff --git a/lib/rss/maker/base.rb b/lib/rss/maker/base.rb
index 0713d276a4..2262a764ec 100644
--- a/lib/rss/maker/base.rb
+++ b/lib/rss/maker/base.rb
@@ -420,11 +420,8 @@ module RSS
         setup_xml_stylesheets(feed)
         setup_elements(feed)
         setup_other_elements(feed)
-        if feed.valid?
-          feed
-        else
-          nil
-        end
+        feed.validate
+        feed
       end
       
       private
diff --git a/test/rss/rss-assertions.rb b/test/rss/rss-assertions.rb
index dd06fb2572..f396e9a446 100644
--- a/test/rss/rss-assertions.rb
+++ b/test/rss/rss-assertions.rb
@@ -1272,22 +1272,32 @@ EOA
                                     invalid_feed_checker=nil)
       _wrap_assertion do
         elements = []
-        invalid_feed = false
-        feed = RSS::Maker.make("atom:#{feed_type}") do |maker|
-          yield maker
-          targets = chain_reader(maker, maker_readers)
-          targets.each do |target|
-            element = maker_extractor.call(target)
-            elements << element if element
+        invalid_feed_exception = nil
+        feed = nil
+        begin
+          feed = RSS::Maker.make("atom:#{feed_type}") do |maker|
+            yield maker
+            targets = chain_reader(maker, maker_readers)
+            targets.each do |target|
+              element = maker_extractor.call(target)
+              elements << element if element
+            end
+            if invalid_feed_checker
+              invalid_feed_exception = invalid_feed_checker.call(targets)
+            end
           end
-          if invalid_feed_checker
-            invalid_feed = invalid_feed_checker.call(targets)
+        rescue RSS::Error
+          if invalid_feed_exception.is_a?(RSS::TooMuchTagError)
+            assert_too_much_tag(invalid_feed_exception.tag,
+                                invalid_feed_exception.parent) do
+              raise
+            end
+          else
+            raise
           end
         end
 
-        if invalid_feed
-          assert_nil(feed)
-        else
+        if invalid_feed_exception.nil?
           actual_elements = chain_reader(feed, feed_readers) || []
           actual_elements = actual_elements.collect do |target|
             feed_extractor.call(target)
@@ -1542,18 +1552,24 @@ EOA
           :length => target.length,
         }
       end
+
+      if feed_readers.first == "entries"
+        parent = "entry"
+      else
+        parent = feed_type
+      end
       invalid_feed_checker = Proc.new do |targets|
         infos = {}
-        invalid = false
+        invalid_exception = nil
         targets.each do |target|
           key = [target.hreflang, target.type]
           if infos.has_key?(key)
-            invalid = true
+            invalid_exception = RSS::TooMuchTagError.new("link", parent)
             break
           end
           infos[key] = true if target.rel.nil? or target.rel == "alternate"
         end
-        invalid
+        invalid_exception
       end
       invalid_feed_checker = nil if allow_duplication
       _assert_maker_atom_elements(feed_type, maker_readers, feed_readers,