Index: fixtures/mail_handler/invalid_utf8.eml
===================================================================
--- fixtures/mail_handler/invalid_utf8.eml	(nonexistent)
+++ fixtures/mail_handler/invalid_utf8.eml	(working copy)
@@ -0,0 +1,14 @@
+From: John Smith <JSmith@somenet.foo>
+To: "redmine@somenet.foo" <redmine@somenet.foo>
+Subject: This is a test
+Content-Type: multipart/alternative;
+  boundary="_c20d9cfa-d16a-43a3-a7e5-71da7877ab23_"
+
+--_c20d9cfa-d16a-43a3-a7e5-71da7877ab23_
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: quoted-printable
+
+=D0=97=D0=B4=D1=80=D0=B0=D0=B2=D1=81=D1=82=D0=B2=D1=83=D0=B9=D1=82=D0=B5=AA
+
+--_c20d9cfa-d16a-43a3-a7e5-71da7877ab23_--
+
Index: unit/mail_handler_test.rb
===================================================================
--- unit/mail_handler_test.rb	(revision 16061)
+++ unit/mail_handler_test.rb	(working copy)
@@ -538,6 +538,16 @@
     assert_equal 'd8e8fca2dc0f896fd7cb4cb0031ba249', attachment.digest
   end
 
+  def test_invalid_utf8
+    issue = submit_email(
+              'invalid_utf8.eml',
+              :issue => {:project => 'ecookbook'}
+            )
+    assert_kind_of Issue, issue
+    description = "\xD0\x97\xD0\xB4\xD1\x80\xD0\xB0\xD0\xB2\xD1\x81\xD1\x82\xD0\xB2\xD1\x83\xD0\xB9\xD1\x82\xD0\xB5?".force_encoding('UTF-8')
+    assert_equal description, issue.description
+  end
+
   def test_gmail_with_attachment_ja
     issue = submit_email(
               'gmail_with_attachment_ja.eml',