1 files changed, 81 insertions, 0 deletions

diff --git a/src/mailman/rules/tests/test_dmarc.py b/src/mailman/rules/tests/test_dmarc.py
new file mode 100644
index 000000000..49aeea8c6
--- /dev/null
+++ b/src/mailman/rules/tests/test_dmarc.py
@@ -0,0 +1,81 @@
+# Copyright (C) 2016 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman 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 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman 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
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Support for mocking dnspython calls from dmarc rules."""
+
+from dns.rdatatype import TXT
+from dns.resolver import NXDOMAIN, NoAnswer
+from mailman import public
+from unittest import mock
+
+
+@public
+def get_dns_resolver():
+    """Create a dns.resolver.Resolver mock.
+
+    This is used to return a predictable response to a _dmarc query.  It
+    returns p=reject for the example.biz domain and raises either NXDOMAIN
+    or NoAnswer for any other.
+
+    It only implements those classes and attributes used by the dmarc rule.
+    """
+    class Name:
+        # mock answer.name
+        def __init__(self):
+            pass
+
+        def to_text(self):
+            return '_dmarc.example.biz.'
+
+    class Item:
+        # mock answer.items
+        def __init__(self):
+            self.strings = [b'v=DMARC1; p=reject;']
+
+    class Ans_e:
+        # mock answer element
+        def __init__(self):
+            self.rdtype = TXT
+            self.items = [Item()]
+            self.name = Name()
+
+    class Answer:
+        # mock answer
+        def __init__(self):
+            self.answer = [Ans_e()]
+
+    class Resolver:
+        # mock dns.resolver.Resolver class.
+        def __init__(self):
+            pass
+
+        def query(self, domain, data_type):
+            if data_type != TXT:
+                raise NoAnswer
+            dparts = domain.split('.')
+            if len(dparts) < 3:
+                raise NXDOMAIN
+            if len(dparts) > 3:
+                raise NoAnswer
+            if dparts[0] != '_dmarc':
+                raise NoAnswer
+            if dparts[1] != 'example' or dparts[2] != 'biz':
+                raise NXDOMAIN
+            self.response = Answer()
+            return self
+    patcher = mock.patch('dns.resolver.Resolver', Resolver)
+    return patcher