bpo-24337: Implement email.message.Message.__repr__()

Lib/email/message.py

@@ -134,6 +134,10 @@ class Message:
         """
         return self.as_string()
 
+    def __repr__(self):
+        return f"{self.__class__.__name__} with {len(self._headers)} " \
+               f"headers and Content-Type {self._default_type}"
+
     def as_string(self, unixfrom=False, maxheaderlen=0, policy=None):
         """Return the entire formatted message as a string.
 

Lib/test/test_email/test_email.py

@@ -302,6 +302,13 @@ class TestMessageAPI(TestEmailBase):
         self.assertTrue(lines[0].startswith('From '))
         self.assertEqual(text, NL.join(lines[1:]))
 
+    def test_repr(self):
+        msg = self._msgobj('msg_01.txt')
+        self.assertIn('Content-Type text/plain', repr(msg))
+        self.assertIn('Message', repr(msg))
+        self.assertEqual(repr(Message()),
+                         'Message with 0 headers and Content-Type text/plain')
+
     def test_as_string_policy(self):
         msg = self._msgobj('msg_01.txt')
         newpolicy = msg.policy.clone(linesep='\r\n')

Misc/NEWS.d/next/Library/2020-01-22-13-19-44.bpo-24337.ORTuPh.rst

@@ -0,0 +1 @@
+Implement ``__repr__()`` for :class:`email.message.Message`.