I initially reported this on launchpad at https://bugs.launchpad.net/bugs/1782647.

I'm running a test for a project that hangs and requires a Control-C to cancel it. The results look like this: https://paste.ubuntu.com/p/SwXsCcghjt/

In narrowing down on this some more, the use of queue.SimpleQueue() seems to make the difference that causes the hang. If I switch that back to queue.Queue() (which was the case for py3.6) the hang goes away:

- self._work_queue = queue.Queue()
+ self._work_queue = queue.SimpleQueue()

To reproduce with OpenStack designate:

git clone https://github.com/openstack/designate.

Then, update tox.ini with the following:

--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.0
-envlist = py35,py27,flake8
+envlist = py35,py37,py27,flake8
 skipsdist = True

 [testenv]
@@ -39,6 +39,12 @@ commands =
   {[testenv]commands}
   stestr run '{posargs}'

+[testenv:py37]
+basepython = python3.7
+commands =
+ {[testenv]commands}
+ stestr run 'designate\.tests\.test_workers\.test_processing\.TestProcessingExecutor\.(test_execute_multiple_tasks)'
+
 [testenv:docs]
 basepython = python3
 deps =


And run: tox -e py37