improve error raise for dialect/pool events w/ async engine

Fixed issues where a descriptive error message was not raised for some
classes of event listening with an async engine, which should instead be a
sync engine instance.

Change-Id: I00b9f4fe9373ef5fd5464fac10651cc4024f648e

1 files changed, 22 insertions, 0 deletions

diff --git a/test/ext/asyncio/test_engine_py3k.py b/test/ext/asyncio/test_engine_py3k.py
index 1f40cbdec..0fe14dc92 100644
--- a/test/ext/asyncio/test_engine_py3k.py
+++ b/test/ext/asyncio/test_engine_py3k.py
@@ -651,6 +651,28 @@ class AsyncEventTest(EngineFixture):
                 event.listen(conn, "before_cursor_execute", mock.Mock())
 
     @async_test
+    async def test_no_async_listeners_dialect_event(self, async_engine):
+        with testing.expect_raises_message(
+            NotImplementedError,
+            "asynchronous events are not implemented "
+            "at this time.  Apply synchronous listeners to the "
+            "AsyncEngine.sync_engine or "
+            "AsyncConnection.sync_connection attributes.",
+        ):
+            event.listen(async_engine, "do_execute", mock.Mock())
+
+    @async_test
+    async def test_no_async_listeners_pool_event(self, async_engine):
+        with testing.expect_raises_message(
+            NotImplementedError,
+            "asynchronous events are not implemented "
+            "at this time.  Apply synchronous listeners to the "
+            "AsyncEngine.sync_engine or "
+            "AsyncConnection.sync_connection attributes.",
+        ):
+            event.listen(async_engine, "checkout", mock.Mock())
+
+    @async_test
     async def test_sync_before_cursor_execute_engine(self, async_engine):
         canary = mock.Mock()