test.py: move mv tests into a separate folder

Now that we support suite subfolders,
As an example, this commit move mv tests into a separate folder

custom test.py lookup also works.
tests can be run as:

1. ./tools/toolchain/dbuild ./test.py --no-gather-metrics --mode=dev topology_custom/mv/tablets/test_mv_tablets_empty_ip
2. ./tools/toolchain/dbuild ./test.py --no-gather-metrics --mode=dev topology_custom/mv/tablets
3. ./tools/toolchain/dbuild ./test.py --no-gather-metrics --mode=dev topology_custom/mv

test/topology_custom/mv/__init__.py

@@ -0,0 +1,5 @@
+#
+# Copyright (C) 2025-present ScyllaDB
+#
+# SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
+#

test/topology_custom/mv/tablets/__init__.py

@@ -0,0 +1,5 @@
+#
+# Copyright (C) 2025-present ScyllaDB
+#
+# SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
+#

test/topology_custom/mv/tablets/test_mv_tablets.py

@@ -12,7 +12,7 @@ from test.pylib.util import wait_for_cql_and_get_hosts
 from test.pylib.internal_types import ServerInfo
 from test.topology.conftest import skip_mode
 
-from .test_alternator import get_alternator, alternator_config, full_query
+from test.topology_custom.test_alternator import get_alternator, alternator_config, full_query
 
 import pytest
 import asyncio

test/topology_custom/mv/tablets/test_mv_tablets_replace.py

@@ -18,7 +18,7 @@ import logging
 
 from test.topology.conftest import skip_mode
 from test.topology.util import get_topology_coordinator, find_server_by_host_id
-from test.topology_custom.test_mv_tablets import get_tablet_replicas
+from test.topology_custom.mv.tablets.test_mv_tablets import get_tablet_replicas
 
 logger = logging.getLogger(__name__)
 

test/topology_custom/mv/test_mv_admission_control.py

@@ -12,7 +12,7 @@ import logging
 
 from test.topology.conftest import skip_mode
 from test.pylib.util import wait_for_view
-from test.topology_custom.test_mv_tablets import pin_the_only_tablet, get_tablet_replicas
+from test.topology_custom.mv.tablets.test_mv_tablets import pin_the_only_tablet, get_tablet_replicas
 
 from cassandra.cluster import ConsistencyLevel, EXEC_PROFILE_DEFAULT # type: ignore
 from cassandra.cqltypes import Int32Type # type: ignore

test/topology_custom/mv/test_mv_backlog.py

@@ -11,7 +11,7 @@ import asyncio
 import pytest
 from test.topology.conftest import skip_mode
 from test.pylib.util import wait_for_view, wait_for
-from test.topology_custom.test_mv_tablets import pin_the_only_tablet
+from test.topology_custom.mv.tablets.test_mv_tablets import pin_the_only_tablet
 from test.pylib.tablets import get_tablet_replica
 
 logger = logging.getLogger(__name__)