feat: add minimal attachments support for email messages

as of now, caller must provide a fully proper MIME attachment.  later
we will add some magic normalization logic so caller can just provide
attachment file paths

src/wuttjamaican/email.py

@@ -166,6 +166,10 @@ class Message:
     .. attribute:: html_body
 
        String with the ``text/html`` body content.
+
+    .. attribute:: attachments
+
+       List of file attachments for the message.
     """
 
     def __init__(
@@ -179,6 +183,7 @@ class Message:
             replyto=None,
             txt_body=None,
             html_body=None,
+            attachments=None,
     ):
         self.key = key
         self.sender = sender
@@ -189,6 +194,7 @@ class Message:
         self.replyto = replyto
         self.txt_body = txt_body
         self.html_body = html_body
+        self.attachments = attachments or []
 
     def set_recips(self, name, value):
         """ """
@@ -224,6 +230,13 @@ class Message:
         if not msg:
             raise ValueError("message has no body parts")
 
+        if self.attachments:
+            for attachment in self.attachments:
+                if isinstance(attachment, str):
+                    raise ValueError("must specify valid MIME attachments; this class cannot "
+                                     "auto-create them from file path etc.")
+            msg = MIMEMultipart(_subtype='mixed', _subparts=[msg] + self.attachments)
+
         msg['Subject'] = self.subject
         msg['From'] = self.sender
 

tests/test_email.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8; -*-
 
+from email.mime.text import MIMEText
 from unittest import TestCase
 from unittest.mock import patch, MagicMock
 
@@ -8,7 +9,7 @@ import pytest
 from wuttjamaican import email as mod
 from wuttjamaican.util import resource_path
 from wuttjamaican.exc import ConfigurationError
-from wuttjamaican.testing import ConfigTestCase
+from wuttjamaican.testing import ConfigTestCase, FileTestCase
 
 
 class TestEmailSetting(ConfigTestCase):
@@ -24,7 +25,7 @@ class TestEmailSetting(ConfigTestCase):
         self.assertEqual(setting.sample_data(), {})
 
 
-class TestMessage(TestCase):
+class TestMessage(FileTestCase):
 
     def make_message(self, **kwargs):
         return mod.Message(**kwargs)
@@ -77,6 +78,26 @@ class TestMessage(TestCase):
         complete = msg.as_string()
         self.assertIn('From: bob@example.com', complete)
 
+        # html + attachment
+        csv_part = MIMEText("foo,bar\n1,2", 'csv', 'utf_8')
+        msg = self.make_message(sender='bob@example.com',
+                                html_body="<p>hello world</p>",
+                                attachments=[csv_part])
+        complete = msg.as_string()
+        self.assertIn('Content-Type: multipart/mixed; boundary=', complete)
+        self.assertIn('Content-Type: text/csv; charset="utf_8"', complete)
+
+        # error if improper attachment
+        csv_path = self.write_file('data.csv', "foo,bar\n1,2")
+        msg = self.make_message(sender='bob@example.com',
+                                html_body="<p>hello world</p>",
+                                attachments=[csv_path])
+        self.assertRaises(ValueError, msg.as_string)
+        try:
+            msg.as_string()
+        except ValueError as err:
+            self.assertIn("must specify valid MIME attachments", str(err))
+
         # everything
         msg = self.make_message(sender='bob@example.com',
                                 subject='meeting follow-up',