From 65813f448e5eeb923cb9c7ae6b06532b6759bd9d Mon Sep 17 00:00:00 2001
From: Alysia Broddrick <abroddrick@truss.works>
Date: Wed, 21 Feb 2024 16:51:57 -0800
Subject: [PATCH] handle 500 error with empty string

---
 src/registrar/models/domain.py                | 13 ++++++++++--
 src/registrar/models/utility/domain_helper.py | 11 +++++-----
 src/registrar/tests/test_models_domain.py     | 20 ++++++++++++++-----
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/src/registrar/models/domain.py b/src/registrar/models/domain.py
index 7ebe3dc34..d7e4a9471 100644
--- a/src/registrar/models/domain.py
+++ b/src/registrar/models/domain.py
@@ -13,6 +13,7 @@ from typing import Any
 from registrar.models.host import Host
 from registrar.models.host_ip import HostIP
 from registrar.utility.enums import DefaultEmail
+from registrar.utility import errors
 
 from registrar.utility.errors import (
     ActionNotAllowed,
@@ -192,9 +193,17 @@ class Domain(TimeStampedModel, DomainHelper):
 
     @classmethod
     def available(cls, domain: str) -> bool:
-        """Check if a domain is available."""
+        """Check if a domain is available.
+        This is called by the availablility api and
+        is called in the validate function on the request/domain page
+
+        throws- RegistryError or InvalidDomainError"""
         if not cls.string_could_be_domain(domain):
-            raise ValueError("Not a valid domain: %s" % str(domain))
+            logger.warning("Not a valid domain: %s" % str(domain))
+            # throw invalid domain error so that it can be caught in
+            # validate_and_handle_errors in domain_helper
+            raise errors.InvalidDomainError()
+
         domain_name = domain.lower()
         req = commands.CheckDomain([domain_name])
         return registry.send(req, cleaned=True).res_data[0].avail
diff --git a/src/registrar/models/utility/domain_helper.py b/src/registrar/models/utility/domain_helper.py
index 9e3559676..8b9391add 100644
--- a/src/registrar/models/utility/domain_helper.py
+++ b/src/registrar/models/utility/domain_helper.py
@@ -33,11 +33,12 @@ class DomainHelper:
         # Split into pieces for the linter
         domain = cls._validate_domain_string(domain, blank_ok)
 
-        try:
-            if not check_domain_available(domain):
-                raise errors.DomainUnavailableError()
-        except RegistryError as err:
-            raise errors.RegistrySystemError() from err
+        if domain != "":
+            try:
+                if not check_domain_available(domain):
+                    raise errors.DomainUnavailableError()
+            except RegistryError as err:
+                raise errors.RegistrySystemError() from err
         return domain
 
     @staticmethod
diff --git a/src/registrar/tests/test_models_domain.py b/src/registrar/tests/test_models_domain.py
index 1c4d2521e..fbf47a745 100644
--- a/src/registrar/tests/test_models_domain.py
+++ b/src/registrar/tests/test_models_domain.py
@@ -20,7 +20,7 @@ from registrar.models.user import User
 from registrar.utility.errors import ActionNotAllowed, NameserverError
 
 from registrar.models.utility.contact_error import ContactError, ContactErrorCodes
-
+from registrar.utility import errors
 
 from django_fsm import TransitionNotAllowed  # type: ignore
 from epplibwrapper import (
@@ -502,16 +502,26 @@ class TestDomainAvailable(MockEppLib):
         self.assertFalse(available)
         patcher.stop()
 
-    def test_domain_available_with_value_error(self):
+    def test_domain_available_with_invalid_error(self):
         """
         Scenario: Testing whether an invalid domain is available
-            Should throw ValueError
+            Should throw InvalidDomainError
 
-            Validate ValueError is raised
+            Validate InvalidDomainError is raised
         """
-        with self.assertRaises(ValueError):
+        with self.assertRaises(errors.InvalidDomainError()):
             Domain.available("invalid-string")
 
+    def test_domain_available_with_empty_string(self):
+        """
+        Scenario: Testing whether an empty string domain name is available
+            Should throw InvalidDomainError
+
+            Validate InvalidDomainError is raised
+        """
+        with self.assertRaises(errors.InvalidDomainError()):
+            Domain.available("")
+
     def test_domain_available_unsuccessful(self):
         """
         Scenario: Testing behavior when registry raises a RegistryError