Fail on alter instead

src/test/regress/sql/failure_on_create_subscription.sql

@@ -32,12 +32,15 @@ INSERT INTO t SELECT x, x+1, MD5(random()::text) FROM generate_series(1,100000)
 -- Initial shard placements
 SELECT * FROM shards_in_workers;
 
--- failure on creating the subscription
+-- Failure on creating the subscription
-SELECT citus.mitmproxy('conn.onQuery(query="CREATE SUBSCRIPTION").kill()');
+-- Failing exactly on CREATE SUBSCRIPTION is causing flaky test where we fail with :
--- Log minimal messages to avoid printing the error message and make the test flaky
+-- 1) ERROR:  connection to the remote node localhost:xxxxx failed with the following error: ERROR:  subscription "citus_shard_move_subscription_xxxxxxx" does not exist
-SET client_min_messages TO ERROR;
+-- another command is already in progress
+-- 2) ERROR:  connection to the remote node localhost:xxxxx failed with the following error: another command is already in progress
+-- Instead fail on the next step (ALTER SUBSCRIPTION) instead which is also required logically as part of CREATE SUBSCRIPTION.
+
+SELECT citus.mitmproxy('conn.onQuery(query="ALTER SUBSCRIPTION").kill()');
 SELECT master_move_shard_placement(101, 'localhost', :worker_1_port, 'localhost', :worker_2_proxy_port);
-RESET client_min_messages;
 
 -- Verify that the shard is not moved and the number of rows are still 100k
 SELECT * FROM shards_in_workers;