Add another test for introspection and cache.

Author: elprans

tests/test_introspection.py

@@ -64,6 +64,8 @@ async def test_introspection_no_stmt_cache_01(self):
 
     @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
+        # the user query and for the introspection query.
         await self.con.fetchval('SELECT $1::int[]', [1, 2])
 
         await self.con.execute('''
@@ -77,3 +79,10 @@ async def test_introspection_no_stmt_cache_02(self):
             await self.con.execute('''
                 DROP EXTENSION hstore
             ''')
+
+    @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])