Fix coordinator join_future race condition (#1338)

* Fix race condition in coordinator join_future handling

1 files changed, 13 insertions, 0 deletions

diff --git a/test/test_coordinator.py b/test/test_coordinator.py
index 7dc0e04..f567369 100644
--- a/test/test_coordinator.py
+++ b/test/test_coordinator.py
@@ -620,3 +620,16 @@ def test_lookup_coordinator_failure(mocker, coordinator):
                         return_value=Future().failure(Exception('foobar')))
     future = coordinator.lookup_coordinator()
     assert future.failed()
+
+
+def test_ensure_active_group(mocker, coordinator):
+    coordinator._subscription.subscribe(topics=['foobar'])
+    mocker.patch.object(coordinator, 'coordinator_unknown', return_value=False)
+    mocker.patch.object(coordinator, '_send_join_group_request', return_value=Future().success(True))
+    mocker.patch.object(coordinator, 'need_rejoin', side_effect=[True, True, False])
+    mocker.patch.object(coordinator, '_on_join_complete')
+    mocker.patch.object(coordinator, '_heartbeat_thread')
+
+    coordinator.ensure_active_group()
+
+    coordinator._send_join_group_request.assert_called_once_with()