test: simplify mocks and localize test fixtures

Replace shared HTTPX and DNS fixtures with targeted unittest.mock
patches close to the tests that need them.

Keep conftest focused on application and client setup, while moving
receiver-specific helpers into the receiver test module.

1 files changed, 10 insertions, 2 deletions

diff --git a/tests/test_forms.py b/tests/test_forms.py
index 2d5fc01..417c655 100644
--- a/tests/test_forms.py
+++ b/tests/test_forms.py
@@ -1,3 +1,5 @@
+from unittest.mock import patch
+
 import pytest
 from flask import Flask
 from werkzeug.datastructures import MultiDict
@@ -8,6 +10,10 @@ VALID_SOURCE = "https://source.example/post"
 VALID_TARGET = "https://dennisfink.me/blog/example/"
 
 
+@patch(
+    "webmentions_ssg.forms.validators.ensure_public_url",
+    new=lambda url: None,
+)
 @pytest.mark.parametrize(
     (
         "form_data",
@@ -89,7 +95,6 @@ VALID_TARGET = "https://dennisfink.me/blog/example/"
 )
 def test_endpoint_form_rejects_invalid_data(
     app: Flask,
-    public_dns: None,
     form_data: dict[str, str],
     invalid_field: str,
     expected_error: str | None,
@@ -110,9 +115,12 @@ def test_endpoint_form_rejects_invalid_data(
             assert expected_error in form.errors[invalid_field]
 
 
+@patch(
+    "webmentions_ssg.forms.validators.ensure_public_url",
+    new=lambda url: None,
+)
 def test_endpoint_form_accepts_valid_data(
     app: Flask,
-    public_dns: None,
 ) -> None:
     with app.test_request_context(
         "/endpoint",