emergency save.

test/mtt_tc.py

@@ -1,6 +1,6 @@
 """Base for MoreThanTest test cases."""
 
-from asyncio import create_subprocess_exec, sleep
+from asyncio import create_subprocess_exec, gather, sleep
 from pathlib import Path
 from socket import socket
 from unittest import IsolatedAsyncioTestCase
@@ -87,6 +87,19 @@ class MTTClusterTC(IsolatedAsyncioTestCase):
         port = await self.get_port()
         await self.create_server_with_flags("-p", str(port))
 
+    async def create_cluster(self, num=2):
+        """Create a cluster of servers."""
+        ports = []
+        while len(ports) < num:
+            port = await self.get_port()
+            if port not in ports:
+                ports.append(port)
+        servers = []
+        for port in ports:
+            servers.append(self.create_server_with_flags("-p", str(port)))
+        cluster = gather(*servers)
+        await cluster
+
     async def run_tests(self, uri, func):
         """Run the tests on each server."""
         for server in self.servers: