added nameserver error class

src/registrar/models/utility/nameserver_error.py

@@ -0,0 +1,49 @@
+from enum import IntEnum
+
+
+class NameserverErrorCodes(IntEnum):
+    """Used in the NameserverError class for
+    error mapping.
+    Overview of nameserver error codes:
+        - 
+    """
+
+    MISSING_IP = 1
+    GLUE_RECORD_NOT_ALLOWED = 2
+    INVALID_IP = 3
+    TOO_MANY_HOSTS=4
+
+
+
+class NameserverError(Exception):
+    """
+    Overview of contact error codes:
+      
+    """
+
+    # For linter
+
+    _error_mapping = {
+        NameserverErrorCodes.MISSING_IP: "Nameserver {} needs to have an "
+                "IP address because it is a subdomain",
+        NameserverErrorCodes.GLUE_RECORD_NOT_ALLOWED: "Nameserver {} cannot be linked "
+                "because it is not a subdomain",
+        NameserverErrorCodes.INVALID_IP:  "Nameserver {} has an invalid IP address: {}",
+         NameserverErrorCodes.TOO_MANY_HOSTS:  "Too many hosts provided, you may not have more than 13 nameservers.",
+
+    }
+
+    def __init__(self, *args, code=None,nameserver=None,ip=None, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.code = code
+        if self.code in self._error_mapping:
+            self.message = self._error_mapping.get(self.code)
+            if nameserver is not None and ip is not None:
+                self.message=self.message.format(str(nameserver),str(ip))
+            elif nameserver is not None:
+                self.message=self.message.format(str(nameserver))
+            elif ip is not None:
+                self.message=self.message.format(str(ip))
+
+    def __str__(self):
+        return f"{self.message}"

src/registrar/tests/test_nameserver_error.py

@@ -0,0 +1,37 @@
+from django.test import TestCase
+
+from registrar.models.utility.nameserver_error import (
+    NameserverError, 
+    NameserverErrorCodes as nsErrorCodes)
+
+
+class TestNameserverError(TestCase):
+
+    def test_with_no_ip(self):
+        """Test NameserverError when no ip address is passed"""
+        nameserver="nameserver val"
+        expected=f"Nameserver {nameserver} needs to have an "\
+                "IP address because it is a subdomain"
+        
+        nsException=NameserverError(code=nsErrorCodes.MISSING_IP,nameserver=nameserver)
+        self.assertEqual(nsException.message,expected)
+        self.assertEqual(nsException.code,nsErrorCodes.MISSING_IP)
+    
+    def test_with_only_code(self):
+        """Test NameserverError when no ip address or nameserver is passed, only the code value"""
+        nameserver="nameserver val"
+        expected="Too many hosts provided, you may not have more than 13 nameservers."
+        
+        nsException=NameserverError(code=nsErrorCodes.TOO_MANY_HOSTS,nameserver=nameserver)
+        self.assertEqual(nsException.message,expected)
+        self.assertEqual(nsException.code,nsErrorCodes.TOO_MANY_HOSTS)
+    
+    def test_with_ip_nameserver(self):
+        """Test NameserverError when ip and nameserver are passed"""
+        ip="ip val"
+        nameserver="nameserver val"
+        
+        expected=f"Nameserver {nameserver} has an invalid IP address: {ip}"
+        nsException=NameserverError(code=nsErrorCodes.INVALID_IP,nameserver=nameserver, ip=ip)
+        self.assertEqual(nsException.message,expected)
+        self.assertEqual(nsException.code,nsErrorCodes.INVALID_IP)