RESOURCE_LOCK
-------------

Specify a list of resources that are locked by this test.

If multiple tests specify the same resource lock, they are guaranteed
not to run concurrently.

See also :prop_test:`FIXTURES_REQUIRED` if the resource requires any setup or
cleanup steps.

Both the :prop_test:`PROCESSES` and ``RESOURCE_LOCK`` properties serve similar
purposes, but they are distinct and orthogonal. Resources specified by
:prop_test:`PROCESSES` do not affect ``RESOURCE_LOCK``, and vice versa. Whereas
``RESOURCE_LOCK`` is a simpler property that is used for locking one global
resource, :prop_test:`PROCESSES` is a more advanced property that allows
multiple tests to simultaneously use multiple resources of the same type,
specifying their requirements in a fine-grained manner.
