Race condition in DockerContainerTestCase

[achave11-ucsc]

… causes the transit failure of various unit tests in the unit test suit due to a required docker container not publishing its ports promptly after creation.

The failure may present itself as …

======================================================================
ERROR: setUpClass (indexer.test_tdr.TestTDRHCAPlugin)
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Traceback (most recent call last):
  File "/Users/achave11/Pycharm/Azul/azul.sc/.venv/lib/python3.11/site-packages/more_itertools/more.py", line 539, in one
    first_value = next(it)
                  ^^^^^^^^
StopIteration

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/achave11/Pycharm/Azul/azul.sc/test/indexer/test_tdr.py", line 190, in setUpClass
    cls.netloc = cls._create_container(image=image,
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/achave11/Pycharm/Azul/azul.sc/test/docker_container_test_case.py", line 94, in _create_container
    port = one(ports[f'{container_port}/tcp'])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/achave11/Pycharm/Azul/azul.sc/.venv/lib/python3.11/site-packages/more_itertools/more.py", line 541, in one
    raise (
ValueError: too few items in iterable (expected 1)

----------------------------------------------------------------------
Ran 432 tests in 760.136s

FAILED (errors=1, skipped=3)
make: *** [test] Error 1

… a ValueError failure in any test class that inherits from DockerContainerTestCase. Alternatively, the ValueError is raised with the last call in the tree like super().setUpClass() followed by the ValueError, and completely omitting the one(ports[f'{container_port}/tcp']) part.