Fixed that MailHandler raises an error when email has no subject header (#12396).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@10850 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/fixtures/mail_handler/no_subject_header.eml

@@ -0,0 +1,10 @@
+Content-Type: application/ms-tnef; name="winmail.dat"
+Content-Transfer-Encoding: binary
+From: John Smith <JSmith@somenet.foo>
+To: "redmine@somenet.foo" <redmine@somenet.foo>
+Date: Fri, 1 Jun 2012 14:39:38 +0200
+Message-ID: <87C31D42249DD0489D1A1444E3232DD7019D6183@foo.bar>
+Accept-Language: de-CH, en-US
+Content-Language: de-CH
+
+Fixture

test/unit/mail_handler_test.rb

@@ -395,6 +395,15 @@ class MailHandlerTest < ActiveSupport::TestCase
     assert_equal ja, issue.subject
   end
 
+  def test_add_issue_with_no_subject_header
+    issue = submit_email(
+              'no_subject_header.eml',
+              :issue => {:project => 'ecookbook'}
+            )
+    assert_kind_of Issue, issue
+    assert_equal '(no subject)', issue.subject
+  end
+
   def test_add_issue_with_mixed_japanese_subject
     issue = submit_email(
               'subject_japanese_2.eml',