test: adding 12 tests for InMemoryQueueManager

[didier-durand]

Description

Hi,

adding 12 tests for InMemoryQueueManager. They all pass: see execution report below

Didier

• Follow the CONTRIBUTING Guide.
• Make your Pull Request title in the https://www.conventionalcommits.org/ specification.

test execution:

============================= test session starts ==============================
collecting ... collected 12 items

server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_init PASSED [  8%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_add_new_queue PASSED [ 16%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_add_existing_queue PASSED [ 25%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_get_existing_queue PASSED [ 33%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_get_nonexistent_queue PASSED [ 41%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_tap_existing_queue PASSED [ 50%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_tap_nonexistent_queue PASSED [ 58%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_close_existing_queue PASSED [ 66%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_close_nonexistent_queue PASSED [ 75%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_create_or_tap_new_queue PASSED [ 83%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_create_or_tap_existing_queue PASSED [ 91%]
server/events/test_inmemory_queue_manager.py::TestInMemoryQueueManager::test_concurrency PASSED [100%]