add checking for file error in rejected licence reply

mail/icms/tasks.py

@@ -20,6 +20,8 @@
 
 logger = logging.getLogger(__name__)
 
+class EdifactFileError(Exception):
+    pass
 
 def process_licence_reply_and_usage_emails():
     """Downloads licenceReply and usageData emails from HMRC mailbox and stores in Mail model."""
@@ -53,12 +55,19 @@ def process_licence_reply_and_usage_emails():
                 elif "usageData" in subject:
                     _save_usage_data_email(mail)
                     con.dele(msg_id)
+
+                elif "Licence rejected by HMRC" in subject:
+                    _check_for_file_errors(mail)
+                    con.dele(msg_id)
+
                 else:
                     raise ValueError(f"Unable to process email with subject: {subject}")
-
+                
         except Exception as e:
             con.rset()
             raise e
+
+
 
 
 @transaction.atomic()
@@ -237,3 +246,8 @@ def _save_usage_data_email(usage_email: email.message.EmailMessage) -> None:
     #     extract_type=ExtractTypeEnum.USAGE_DATA
     # )
     raise NotImplementedError
+
+def _check_for_file_errors(reply_email: email.message.EmailMessage) -> None:
+    processor = LicenceReplyProcessor.load_from_mail(reply_email)
+    if file_error in processor.file_errors:
+        raise EdifactFileError(f"Unable to process file due to the following errors: {error for file_error in processor.file_errors}")