2 files changed, 25 insertions, 17 deletions

diff --git a/src/mailman/model/docs/addresses.rst b/src/mailman/model/docs/addresses.rst
index 795afe43c..9f34efdec 100644
--- a/src/mailman/model/docs/addresses.rst
+++ b/src/mailman/model/docs/addresses.rst
@@ -205,23 +205,9 @@ case-preserved version are available on attributes of the `IAddress` object.
     FPERSON@example.com
 
 Because addresses are case-insensitive for all other purposes, you cannot
-create an address that differs only in case.
-
-    >>> user_manager.create_address('fperson@example.com')
-    Traceback (most recent call last):
-    ...
-    ExistingAddressError: FPERSON@example.com
-    >>> user_manager.create_address('fperson@EXAMPLE.COM')
-    Traceback (most recent call last):
-    ...
-    ExistingAddressError: FPERSON@example.com
-    >>> user_manager.create_address('FPERSON@example.com')
-    Traceback (most recent call last):
-    ...
-    ExistingAddressError: FPERSON@example.com
-
-You can get the address using either the lower cased version or case-preserved
-version.  In fact, searching for an address is case insensitive.
+create an address that differs only in case.  You can get the address using
+either the lower cased version or case-preserved version.  In fact, searching
+for an address is case insensitive.
 
     >>> print(user_manager.get_address('fperson@example.com').email)
     fperson@example.com
diff --git a/src/mailman/model/tests/test_address.py b/src/mailman/model/tests/test_address.py
index 130ec3bae..7de77c019 100644
--- a/src/mailman/model/tests/test_address.py
+++ b/src/mailman/model/tests/test_address.py
@@ -28,8 +28,11 @@ __all__ = [
 import unittest
 
 from mailman.email.validate import InvalidEmailAddressError
+from mailman.interfaces.address import ExistingAddressError
+from mailman.interfaces.usermanager import IUserManager
 from mailman.model.address import Address
 from mailman.testing.layers import ConfigLayer
+from zope.component import getUtility
 
 
 
@@ -38,6 +41,25 @@ class TestAddress(unittest.TestCase):
 
     layer = ConfigLayer
 
+    def setUp(self):
+        self._usermgr = getUtility(IUserManager)
+        self._address = self._usermgr.create_address('FPERSON@example.com')
+
     def test_invalid_email_string_raises_exception(self):
         with self.assertRaises(InvalidEmailAddressError):
             Address('not_a_valid_email_string', '')
+
+    def test_local_part_differs_only_by_case(self):
+        with self.assertRaises(ExistingAddressError) as cm:
+            self._usermgr.create_address('fperson@example.com')
+        self.assertEqual(cm.exception.address, 'FPERSON@example.com')
+
+    def test_domain_part_differs_only_by_case(self):
+        with self.assertRaises(ExistingAddressError) as cm:
+            self._usermgr.create_address('fperson@EXAMPLE.COM')
+        self.assertEqual(cm.exception.address, 'FPERSON@example.com')
+
+    def test_mixed_case_exact_match(self):
+        with self.assertRaises(ExistingAddressError) as cm:
+            self._usermgr.create_address('FPERSON@example.com')
+        self.assertEqual(cm.exception.address, 'FPERSON@example.com')