diff --git a/app/helpers/search_helper.rb b/app/helpers/search_helper.rb
index 32ff16f67..640b5a907 100644
--- a/app/helpers/search_helper.rb
+++ b/app/helpers/search_helper.rb
@@ -27,8 +27,9 @@ module SearchHelper
         result << '...'
         break
       end
+      words = words.mb_chars
       if i.even?
-        result << h(words.length > 100 ? "#{words[0..44]} ... #{words[-45..-1]}" : words)
+        result << h(words.length > 100 ? "#{words.slice(0..44)} ... #{words.slice(-45..-1)}" : words)
       else
         t = (tokens.index(words.downcase) || 0) % 4
         result << content_tag('span', h(words), :class => "highlight token-#{t}")
diff --git a/test/unit/helpers/search_helper_test.rb b/test/unit/helpers/search_helper_test.rb
new file mode 100644
index 000000000..6616fcb1a
--- /dev/null
+++ b/test/unit/helpers/search_helper_test.rb
@@ -0,0 +1,45 @@
+# Redmine - project management software
+# Copyright (C) 2006-2009  Jean-Philippe Lang
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+require File.dirname(__FILE__) + '/../../test_helper'
+
+class SearchHelperTest < HelperTestCase
+  include SearchHelper
+  
+  def test_highlight_single_token
+    assert_equal 'This is a <span class="highlight token-0">token</span>.',
+                 highlight_tokens('This is a token.', %w(token))
+  end
+  
+  def test_highlight_multiple_tokens
+    assert_equal 'This is a <span class="highlight token-0">token</span> and <span class="highlight token-1">another</span> <span class="highlight token-0">token</span>.',
+                 highlight_tokens('This is a token and another token.', %w(token another))
+  end
+  
+  def test_highlight_should_not_exceed_maximum_length
+    s = (('1234567890' * 100) + ' token ') * 100
+    r = highlight_tokens(s, %w(token))
+    assert r.include?('<span class="highlight token-0">token</span>')
+    assert r.length <= 1300
+  end
+  
+  def test_highlight_multibyte
+    s = ('й' * 200) + ' token ' + ('й' * 200)
+    r = highlight_tokens(s, %w(token))
+    assert_equal  ('й' * 45) + ' ... ' + ('й' * 44) + ' <span class="highlight token-0">token</span> ' + ('й' * 44) + ' ... ' + ('й' * 45), r
+  end
+end