pgtest: add test for multiple DDL statements in one extended req

test/pgtest/ddl-extended.pt

@@ -1,3 +1,44 @@
+# Test that multiple DDL statements in the same extended request are supported
+send
+Parse {"query": "CREATE TABLE a (a int)"}
+Bind
+Execute
+Parse {"query": "ROLLBACK"}
+Bind
+Execute
+Parse {"query": "CREATE TABLE b (a int)"}
+Bind
+Execute
+Parse {"query": "SELECT * FROM a"}
+Bind
+Execute
+Parse {"query": "SELECT * FROM b"}
+Bind
+Execute
+Sync
+----
+
+until
+ReadyForQuery
+----
+ParseComplete
+BindComplete
+CommandComplete {"tag":"CREATE TABLE"}
+ParseComplete
+BindComplete
+NoticeResponse {"fields":[{"typ":"S","value":"WARNING"},{"typ":"C","value":"25P01"},{"typ":"M","value":"there is no transaction in progress"}]}
+CommandComplete {"tag":"ROLLBACK"}
+ParseComplete
+BindComplete
+CommandComplete {"tag":"CREATE TABLE"}
+ParseComplete
+BindComplete
+CommandComplete {"tag":"SELECT 0"}
+ParseComplete
+BindComplete
+CommandComplete {"tag":"SELECT 0"}
+ReadyForQuery {"status":"I"}
+
 # Test what happens with rollback'd DDLs in extended protocol.
 #
 # Note: This only works in versions of Postgres with