changed endpoint for check availability to pass domain as parameter; wrote unit test for extra dot validation in form

src/api/views.py

@@ -82,6 +82,7 @@ def available(request, domain=""):
     Response is a JSON dictionary with the key "available" and value true or
     false.
     """
+    domain = request.GET.get('domain', '')
     DraftDomain = apps.get_model("registrar.DraftDomain")
     # validate that the given domain could be a domain name and fail early if
     # not.

src/registrar/assets/js/get-gov.js

@@ -73,6 +73,7 @@ function debounce(handler, cooldown=600) {
 
 /** Asyncronously fetches JSON. No error handling. */
 function fetchJSON(endpoint, callback, url="/api/v1/") {
+    console.log("fetchJSON called for endpoint " + endpoint);
     const xhr = new XMLHttpRequest();
     xhr.open('GET', url + endpoint);
     xhr.send();
@@ -142,7 +143,7 @@ function _checkDomainAvailability(el) {
       inlineToast(el.parentElement, el.id, ERROR, response.message);
     }
   }
-  fetchJSON(`available/${el.value}`, callback);
+  fetchJSON(`available/?domain=${el.value}`, callback);
 }
 
 /** Call the API to see if the domain is good. */

src/registrar/config/urls.py

@@ -72,7 +72,7 @@ urlpatterns = [
     path("health/", views.health),
     path("openid/", include("djangooidc.urls")),
     path("register/", include((application_urls, APPLICATION_NAMESPACE))),
-    path("api/v1/available/<domain>", available, name="available"),
+    path("api/v1/available/", available, name="available"),
     path(
         "todo",
         lambda r: always_404(r, "We forgot to include this link, sorry."),

src/registrar/tests/test_forms.py

@@ -74,6 +74,24 @@ class TestFormValidation(MockEppLib):
             ["Enter the .gov domain you want without any periods."],
         )
 
+    def test_requested_domain_two_dots_invalid(self):
+        """don't accept domains that are subdomains"""
+        form = DotGovDomainForm(data={"requested_domain": "sub.top-level-agency.gov"})
+        self.assertEqual(
+            form.errors["requested_domain"],
+            ["Enter the .gov domain you want without any periods."],
+        )
+        form = DotGovDomainForm(data={"requested_domain": ".top-level-agency.gov"})
+        self.assertEqual(
+            form.errors["requested_domain"],
+            ["Enter the .gov domain you want without any periods."],
+        )
+        form = DotGovDomainForm(data={"requested_domain": "..gov"})
+        self.assertEqual(
+            form.errors["requested_domain"],
+            ["Enter the .gov domain you want without any periods."],
+        )
+    
     def test_requested_domain_invalid_characters(self):
         """must be a valid .gov domain name."""
         form = DotGovDomainForm(data={"requested_domain": "underscores_forever"})