test: cross-file stub-scoping repairs — hub ConfigFlow base carries the full plumbing, standalone rebuilds when its holder is gone, test_init scoped hygiene mirrors scoped_stubs (completes t30 G6)

tests/entity_stublib.py

@@ -131,8 +131,38 @@ def install() -> None:
 
     config_entries = types.ModuleType("homeassistant.config_entries")
     config_entries.ConfigEntry = type("ConfigEntry", (), {})
+    async def _stub_set_unique_id(self, unique_id):
+        # hub shape: record; a full flow test file scopes its own version
+        self._unique_id = unique_id
+
+    def _noop_abort(self, *, error=None, **kwargs):
+        return None
+
     class _ConfigFlowStub:
-        """ConfigFlow shape used by flow tests (t29 G3a API included)."""
+        """ConfigFlow shape used by entity tests (t29 G3a API included).
+
+        Late loads under the hub stubs (e.g. test_init designs run AFTER the
+        other flow files) still get the base plumbing the flow modules rely
+        on — show/create/abort/unique-id — so the flow classes never import
+        against a bare base.
+        """
+
+        async_set_unique_id = _stub_set_unique_id
+        _abort_if_unique_id_configured = _noop_abort
+
+        def async_show_form(self, *, step_id, data_schema=None, errors=None):
+            return {
+                "type": "form",
+                "step_id": step_id,
+                "errors": dict(errors or {}),
+                "data_schema": data_schema,
+            }
+
+        def async_create_entry(self, *, title, data, options=None):
+            return {"type": "create_entry", "title": title, "data": data}
+
+        def async_abort(self, *, reason):
+            return {"type": "abort", "reason": reason}
 
         def _get_reauth_entry(self, entry=None):
             if entry is not None: