test: scope auto resource fixtures

tests/unit/auto_resource_test_plugin.py

@@ -1,4 +1,4 @@
-"""Fixtures shared by focused unit-test modules."""
+"""Pytest fixtures loaded only by the auto-resource test modules."""
 
 from .auto_resource_test_support import auto_resource_env
 

tests/unit/test_auto_image_steps.py

@@ -49,6 +49,8 @@ from .auto_resource_test_support import (
     write_note as _write_note,
 )
 
+pytest_plugins = ("unit.auto_resource_test_plugin",)
+
 
 @pytest.mark.parametrize(
     ("image_format", "suffix", "source_mime", "request_mime"),

tests/unit/test_auto_resource_review_regressions.py

@@ -12,6 +12,7 @@ from .auto_resource_test_support import (
     write_note,
 )
 
+pytest_plugins = ("unit.auto_resource_test_plugin",)
 pytestmark = pytest.mark.asyncio