diff --git a/api/desecapi/tests/test_donations.py b/api/desecapi/tests/test_donations.py
index 3ce6585fd..40fc85e4a 100644
--- a/api/desecapi/tests/test_donations.py
+++ b/api/desecapi/tests/test_donations.py
@@ -20,7 +20,34 @@ def test_create_donation_minimal(self):
         }
         response = self.client.post(url, data)
         self.assertTrue(mail.outbox)
-        email_internal = str(mail.outbox[0].message())
+
+        import copy
+        from base64 import b64encode
+        from django.core.mail.message import SafeMIMEText
+
+        class Mock(SafeMIMEText):
+            def __new__(cls, *args, **kwargs):
+                if args and isinstance(args[0], SafeMIMEText):
+                    other = copy.copy(args[0])
+                    other.__class__ = Mock
+                    return other
+                return object.__new__(cls)
+
+            def __init__(self, other):
+                pass
+
+            def set_payload(self, payload, *args, **kwargs):
+                print("set_payload", b64encode(payload.encode()))
+
+        msg = mail.outbox[0].message()
+        msg._payload = [Mock(o) for o in msg._payload]
+        #print(msg._payload)
+        #print(
+        #    "DEBUG1",
+        #    [b64encode(o.as_bytes()) for o in msg._payload],
+        #)
+        #print("DEBUG2", b64encode(msg.as_bytes()))
+        email_internal = str(msg)
         direct_debit = str(mail.outbox[0].attachments[0][1])
         reply_to = mail.outbox[0].reply_to
         self.assertStatus(response, status.HTTP_201_CREATED)