1 files changed, 62 insertions, 29 deletions

diff --git a/Lib/test/test_email/test_parser.py b/Lib/test/test_email/test_parser.py
index 8ddc176389..06c86408ab 100644
--- a/Lib/test/test_email/test_parser.py
+++ b/Lib/test/test_email/test_parser.py
@@ -1,7 +1,7 @@
 import io
 import email
 import unittest
-from email.message import Message
+from email.message import Message, EmailMessage
 from email.policy import default
 from test.test_email import TestEmailBase
 
@@ -39,38 +39,71 @@ class TestParserBase:
         # The unicode line splitter splits on unicode linebreaks, which are
         # more numerous than allowed by the email RFCs; make sure we are only
         # splitting on those two.
-        msg = self.parser(
-            "Next-Line: not\x85broken\r\n"
-            "Null: not\x00broken\r\n"
-            "Vertical-Tab: not\vbroken\r\n"
-            "Form-Feed: not\fbroken\r\n"
-            "File-Separator: not\x1Cbroken\r\n"
-            "Group-Separator: not\x1Dbroken\r\n"
-            "Record-Separator: not\x1Ebroken\r\n"
-            "Line-Separator: not\u2028broken\r\n"
-            "Paragraph-Separator: not\u2029broken\r\n"
-            "\r\n",
-            policy=default,
-        )
-        self.assertEqual(msg.items(), [
-            ("Next-Line", "not\x85broken"),
-            ("Null", "not\x00broken"),
-            ("Vertical-Tab", "not\vbroken"),
-            ("Form-Feed", "not\fbroken"),
-            ("File-Separator", "not\x1Cbroken"),
-            ("Group-Separator", "not\x1Dbroken"),
-            ("Record-Separator", "not\x1Ebroken"),
-            ("Line-Separator", "not\u2028broken"),
-            ("Paragraph-Separator", "not\u2029broken"),
-        ])
-        self.assertEqual(msg.get_payload(), "")
+        for parser in self.parsers:
+            with self.subTest(parser=parser.__name__):
+                msg = parser(
+                    "Next-Line: not\x85broken\r\n"
+                    "Null: not\x00broken\r\n"
+                    "Vertical-Tab: not\vbroken\r\n"
+                    "Form-Feed: not\fbroken\r\n"
+                    "File-Separator: not\x1Cbroken\r\n"
+                    "Group-Separator: not\x1Dbroken\r\n"
+                    "Record-Separator: not\x1Ebroken\r\n"
+                    "Line-Separator: not\u2028broken\r\n"
+                    "Paragraph-Separator: not\u2029broken\r\n"
+                    "\r\n",
+                    policy=default,
+                )
+                self.assertEqual(msg.items(), [
+                    ("Next-Line", "not\x85broken"),
+                    ("Null", "not\x00broken"),
+                    ("Vertical-Tab", "not\vbroken"),
+                    ("Form-Feed", "not\fbroken"),
+                    ("File-Separator", "not\x1Cbroken"),
+                    ("Group-Separator", "not\x1Dbroken"),
+                    ("Record-Separator", "not\x1Ebroken"),
+                    ("Line-Separator", "not\u2028broken"),
+                    ("Paragraph-Separator", "not\u2029broken"),
+                ])
+                self.assertEqual(msg.get_payload(), "")
+
+    class MyMessage(EmailMessage):
+        pass
+
+    def test_custom_message_factory_on_policy(self):
+        for parser in self.parsers:
+            with self.subTest(parser=parser.__name__):
+                MyPolicy = default.clone(message_factory=self.MyMessage)
+                msg = parser("To: foo\n\ntest", policy=MyPolicy)
+                self.assertIsInstance(msg, self.MyMessage)
+
+    def test_factory_arg_overrides_policy(self):
+        for parser in self.parsers:
+            with self.subTest(parser=parser.__name__):
+                MyPolicy = default.clone(message_factory=self.MyMessage)
+                msg = parser("To: foo\n\ntest", Message, policy=MyPolicy)
+                self.assertNotIsInstance(msg, self.MyMessage)
+                self.assertIsInstance(msg, Message)
+
+# Play some games to get nice output in subTest.  This code could be clearer
+# if staticmethod supported __name__.
+
+def message_from_file(s, *args, **kw):
+    f = io.StringIO(s)
+    return email.message_from_file(f, *args, **kw)
 
 class TestParser(TestParserBase, TestEmailBase):
-    parser = staticmethod(email.message_from_string)
+    parsers = (email.message_from_string, message_from_file)
+
+def message_from_bytes(s, *args, **kw):
+    return email.message_from_bytes(s.encode(), *args, **kw)
+
+def message_from_binary_file(s, *args, **kw):
+    f = io.BytesIO(s.encode())
+    return email.message_from_binary_file(f, *args, **kw)
 
 class TestBytesParser(TestParserBase, TestEmailBase):
-    def parser(self, s, *args, **kw):
-        return email.message_from_bytes(s.encode(), *args, **kw)
+    parsers = (message_from_bytes, message_from_binary_file)
 
 
 if __name__ == '__main__':