- An event listener can now be associated with a :class:`.Engine`,

after one or more :class:`.Connection` objects have been created
(such as by an orm :class:`.Session` or via explicit connect)
and the listener will pick up events from those connections.
Previously, performance concerns pushed the event transfer from
:class:`.Engine` to  :class:`.Connection` at init-time only, but
we've inlined a bunch of conditional checks to make this possible
without any additional function calls. fixes #2978

1 files changed, 33 insertions, 0 deletions

diff --git a/test/engine/test_execute.py b/test/engine/test_execute.py
index d3ae309c3..3bdf34176 100644
--- a/test/engine/test_execute.py
+++ b/test/engine/test_execute.py
@@ -1248,6 +1248,39 @@ class EngineEventsTest(fixtures.TestBase):
         eq_(canary.be1.call_count, 2)
         eq_(canary.be2.call_count, 2)
 
+    def test_add_event_after_connect(self):
+        # new feature as of #2978
+        canary = Mock()
+        e1 = create_engine(config.db_url)
+        assert not e1._has_events
+
+        conn = e1.connect()
+
+        event.listen(e1, "before_execute", canary.be1)
+        conn.execute(select([1]))
+
+        eq_(canary.be1.call_count, 1)
+
+        conn._branch().execute(select([1]))
+        eq_(canary.be1.call_count, 2)
+
+    def test_force_conn_events_false(self):
+        canary = Mock()
+        e1 = create_engine(config.db_url)
+        assert not e1._has_events
+
+        event.listen(e1, "before_execute", canary.be1)
+
+        conn = e1._connection_cls(e1, connection=e1.raw_connection(),
+                            _has_events=False)
+
+        conn.execute(select([1]))
+
+        eq_(canary.be1.call_count, 0)
+
+        conn._branch().execute(select([1]))
+        eq_(canary.be1.call_count, 0)
+
     def test_cursor_events_ctx_execute_scalar(self):
         canary = Mock()
         e1 = testing_engine(config.db_url)