add more tests, refactor sign and encrypt

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>

smtprd_ng/smtprd.py

@@ -147,7 +147,7 @@ class Config:
 class SMTPClient(SMTP):
     """Client part of library
 
-    This will connect to an upstream SMTP server to deliver the mal
+    This will connect to an upstream SMTP server to deliver the mail
 
     """
 
@@ -206,7 +206,7 @@ class SMTPClient(SMTP):
             message (Message): message object
 
         Returns:
-            bytes: The signed message including the From and To Header
+            bytes: The signed message
         """
         with open(Path(self._config.smime_cert_private), "rb") as key_data:
             key = load_pem_private_key(key_data.read(), password=None)
@@ -220,12 +220,20 @@ class SMTPClient(SMTP):
             .add_signer(cert, key, hashes.SHA512(), rsa_padding=padding.PKCS1v15())
             .sign(Encoding.SMIME, [pkcs7.PKCS7Options.DetachedSignature])
         )
-        # Add correct headers
-        # new = b"From: " + self._config.sender.encode() + b"\r\n" + output
-        # new = b"To: " + ", ".join(self._config.recipients).encode() + b"\r\n" + new
-        # new = b"Subject: " + message.get("Subject", "").encode() + b"\r\n" + new
-        new = self._encrypt(output, message.get("Subject", ""))
-        return new
+        return output
+
+    def _encrypt_and_sign(self, message: Message) -> bytes:
+        """Sign and encrypt the message
+
+        Args:
+            message (Message): message object
+
+        Returns:
+            bytes: The signed and encrypted message including the From and To Header
+        """
+        signed = self._sign(message)
+        encrypt = self._encrypt(signed, message.get("Subject", ""))
+        return encrypt
 
     async def _send_message(
         self, message: bytes, sender: str, recipients: List[str]
@@ -275,7 +283,7 @@ class SMTPClient(SMTP):
             f"'{message.get('Subject', '')}'"
         )
         if self._config.smime_cert:
-            message = self._sign(message)
+            message = self._encrypt_and_sign(message)
         async with (
             self._lock
         ):  # TODO: consumer task from spool queue, reusing connections