Add explicit checks for the number of prepared statements.

Author: elprans

tests/test_introspection.py

@@ -62,6 +62,8 @@ async def test_introspection_no_stmt_cache_01(self):
                 DROP EXTENSION hstore
             ''')
 
+        self.assertEqual(self.con._uid, 0)
+
     @tb.with_connection_options(max_cacheable_statement_size=1)
     async def test_introspection_no_stmt_cache_02(self):
         # max_cacheable_statement_size will disable caching both for
@@ -80,9 +82,13 @@ async def test_introspection_no_stmt_cache_02(self):
                 DROP EXTENSION hstore
             ''')
 
+        self.assertEqual(self.con._uid, 0)
+
     @tb.with_connection_options(max_cacheable_statement_size=10000)
     async def test_introspection_no_stmt_cache_03(self):
         # max_cacheable_statement_size will disable caching for
         # the user query but not for the introspection query.
         await self.con.fetchval(
             "SELECT $1::int[], '{foo}'".format(foo='a' * 10000), [1, 2])
+
+        self.assertEqual(self.con._uid, 1)