Add unit tests

src/registrar/forms/application_wizard.py

@@ -2,6 +2,7 @@ from __future__ import annotations  # allows forward references in annotations
 from itertools import zip_longest
 import logging
 from typing import Callable
+from api.views import DOMAIN_API_MESSAGES
 from phonenumber_field.formfields import PhoneNumberField  # type: ignore
 
 from django import forms
@@ -469,7 +470,12 @@ class DotGovDomainForm(RegistrarForm):
         )
         return validated
 
-    requested_domain = forms.CharField(label="What .gov domain do you want?")
+    requested_domain = forms.CharField(
+        label="What .gov domain do you want?",
+        error_messages={
+            "required": DOMAIN_API_MESSAGES["required"],
+        },
+    )
 
 
 class PurposeForm(RegistrarForm):

src/registrar/models/utility/domain_helper.py

@@ -94,15 +94,11 @@ class DomainHelper:
             error_type = type(error)
 
             # Generate the response based on the error code and return type
-            response = DomainHelper._return_form_error_or_json_response(
-                return_type, code=error_map.get(error_type)
-            )
+            response = DomainHelper._return_form_error_or_json_response(return_type, code=error_map.get(error_type))
         else:
             # For form validation, we do not need to display the success message
             if return_type != ValidationReturnType.FORM_VALIDATION_ERROR:
-                response = DomainHelper._return_form_error_or_json_response(
-                    return_type, code="success", available=True
-                )
+                response = DomainHelper._return_form_error_or_json_response(return_type, code="success", available=True)
 
         # Return the validated domain and the response (either error or success)
         return (validated, response)

src/registrar/tests/test_forms.py

@@ -2,7 +2,6 @@
 
 import json
 from django.test import TestCase, RequestFactory
-from django.urls import reverse
 from api.views import available
 
 from registrar.forms.application_wizard import (
@@ -92,7 +91,12 @@ class TestFormValidation(MockEppLib):
                 "Enter a domain using only letters, numbers, " "or hyphens (though we don't recommend using hyphens).",
             ),
             # required
-            ("", "Enter the .gov domain you want. Don’t include “www” or “.gov.”"),
+            (
+                "",
+                "Enter the .gov domain you want. Don’t include “www” or “.gov.”"
+                " For example, if you want www.city.gov, you would enter “city”"
+                " (without the quotes).",
+            ),
             # unavailable
             (
                 "whitehouse.gov",
@@ -143,8 +147,6 @@ class TestFormValidation(MockEppLib):
                 "underscores_forever",
                 "Enter a domain using only letters, numbers, " "or hyphens (though we don't recommend using hyphens).",
             ),
-            # required
-            ("", "Enter the .gov domain you want. Don’t include “www” or “.gov.”"),
             # unavailable
             (
                 "whitehouse.gov",