clickhouse: Fix insertion race condition in test

This commit makes replicas in Clickhouse tests synchronize before
checking if expected data is present. It eliminates situation when
one replica did not pass a fresh data to another one.

[DDB-906]

tests/integration/coordinator/plugins/clickhouse/test_plugin.py

@@ -9,6 +9,7 @@
 from astacus.coordinator.plugins.clickhouse.client import (
     ClickHouseClient,
     ClickHouseClientQueryError,
+    escape_sql_identifier,
     escape_sql_string,
     HttpClickHouseClient,
 )
@@ -158,6 +159,7 @@ async def fixture_restored_cluster(
     async with restored_cluster_manager(
         restorable_cluster, ports, stop_after_step, clickhouse_restore_command, minio_bucket
     ) as clients:
+        await sync_replicated_tables(clients)
         yield clients
 
 
@@ -175,6 +177,18 @@ async def fixture_function_restored_cluster(
             yield clients
 
 
+async def sync_replicated_tables(clients: Sequence[ClickHouseClient]) -> None:
+    # Get replicated tables to sync
+    rows = await clients[0].execute(
+        b"SELECT name FROM system.tables WHERE database = 'default' AND engine like 'Replicated%'"
+    )
+    for client in clients:
+        for row in rows:
+            table_name = row[0]
+            assert isinstance(table_name, str)
+            await client.execute(f"SYSTEM SYNC REPLICA default.{escape_sql_identifier(table_name.encode())} STRICT".encode())
+
+
 async def setup_cluster_content(clients: Sequence[HttpClickHouseClient], use_named_collections: bool) -> None:
     for client in clients:
         await client.execute(b"DROP DATABASE default SYNC")