Refs #27236 -- Reverted "Refs #27236 -- Added generic mechanism to handle the deprecation of migration operations."

This reverts commit 41019e48bb.

tests/postgres_tests/migrations/0001_setup_extensions.py

@@ -1,17 +1,6 @@
+from unittest import mock
+
 from django.db import connection, migrations
-from django.db.migrations.operations.base import Operation
-
-
-class DummyOperation(Operation):
-    def state_forwards(self, app_label, state):
-        pass
-
-    def database_forwards(self, app_label, schema_editor, from_state, to_state):
-        pass
-
-    def database_backwards(self, app_label, schema_editor, from_state, to_state):
-        pass
-
 
 try:
     from django.contrib.postgres.operations import (
@@ -26,14 +15,14 @@ try:
         UnaccentExtension,
     )
 except ImportError:
-    BloomExtension = DummyOperation
-    BtreeGinExtension = DummyOperation
-    BtreeGistExtension = DummyOperation
-    CITextExtension = DummyOperation
-    CreateExtension = DummyOperation
-    HStoreExtension = DummyOperation
-    TrigramExtension = DummyOperation
-    UnaccentExtension = DummyOperation
+    BloomExtension = mock.Mock()
+    BtreeGinExtension = mock.Mock()
+    BtreeGistExtension = mock.Mock()
+    CITextExtension = mock.Mock()
+    CreateExtension = mock.Mock()
+    HStoreExtension = mock.Mock()
+    TrigramExtension = mock.Mock()
+    UnaccentExtension = mock.Mock()
     needs_crypto_extension = False
 else:
     needs_crypto_extension = (
@@ -52,7 +41,7 @@ class Migration(migrations.Migration):
         # dash in its name.
         CreateExtension("uuid-ossp"),
         # CryptoExtension is required for RandomUUID() on PostgreSQL < 13.
-        CryptoExtension() if needs_crypto_extension else DummyOperation(),
+        CryptoExtension() if needs_crypto_extension else mock.Mock(),
         HStoreExtension(),
         TrigramExtension(),
         UnaccentExtension(),