test: fix system engine tests (#365)

Author: ptiurin

tests/integration/dbapi/async/V2/test_system_engine_async.py

@@ -48,8 +48,11 @@ async def test_system_engine(
 
         if connection_system_engine.database:
             await c.execute("show tables")
+            await c.execute(
+                "create table if not exists test_async(id int) primary index id"
+            )
             with raises(OperationalError):
-                await c.execute("create table test(id int) primary index id")
+                await c.execute("insert into test values (1)")
         else:
             await c.execute("show databases")
             with raises(OperationalError):

tests/integration/dbapi/sync/V2/test_system_engine.py

@@ -48,8 +48,9 @@ def test_system_engine(
 
         if connection_system_engine.database:
             c.execute("show tables")
+            c.execute("create table if not exists test_sync(id int) primary index id")
             with raises(OperationalError):
-                c.execute("create table test(id int) primary index id")
+                c.execute("insert into test values (1)")
         else:
             c.execute("show databases")
             with raises(OperationalError):