diff --git a/lib/redmine/export/pdf.rb b/lib/redmine/export/pdf.rb
index 45d5245..5242cb3 100644
--- a/lib/redmine/export/pdf.rb
+++ b/lib/redmine/export/pdf.rb
@@ -1,3 +1,5 @@
+# encoding: utf-8
+#
 # Redmine - project management software
 # Copyright (C) 2006-2009  Jean-Philippe Lang
 #
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 4ae8964..7b289d5 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -1,3 +1,5 @@
+# encoding: utf-8
+#
 # redMine - project management software
 # Copyright (C) 2006-2007  Jean-Philippe Lang
 #
diff --git a/test/unit/helpers/search_helper_test.rb b/test/unit/helpers/search_helper_test.rb
index 6616fcb..258e6a3 100644
--- a/test/unit/helpers/search_helper_test.rb
+++ b/test/unit/helpers/search_helper_test.rb
@@ -1,3 +1,5 @@
+# encoding: utf-8
+#
 # Redmine - project management software
 # Copyright (C) 2006-2009  Jean-Philippe Lang
 #
diff --git a/test/unit/wiki_test.rb b/test/unit/wiki_test.rb
index ed96e07..6595e6d 100644
--- a/test/unit/wiki_test.rb
+++ b/test/unit/wiki_test.rb
@@ -1,3 +1,5 @@
+# encoding: utf-8
+#
 # redMine - project management software
 # Copyright (C) 2006-2007  Jean-Philippe Lang
 #