Stx/config/sysinv unit tests fail in python3.9 environment

[Dan Voiculeasa]

Brief Description
-----------------
Working towards migrating to Debian OS.
Enabling tox tests in a Python3.9 environment: https://review.opendev.org/c/starlingx/config/+/804086
Tox tests fail.

Fixing some of the issues:
https://review.opendev.org/c/starlingx/config/+/804850
https://review.opendev.org/c/starlingx/config/+/804851
Cherry-pick to master of: https://review.opendev.org/c/starlingx/config/+/803591

There is still one more issue.

Severity
--------
Minor

Steps to Reproduce
------------------
tox -e py39

Expected Behavior
------------------
tests pass

Actual Behavior
----------------
A few tests fail with sqlalchemy.orm.exc.DetachedInstanceError

Reproducibility
---------------
100%

System Configuration
--------------------
-

Branch/Pull Time/Commit
-----------------------
August 2021

Last Pass
---------
-

Timestamp/Logs
-----------tests.api.test_sensorgroup.sensorgroupTestCase.test_sensor_post
---------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/tests/api/test_sensorgroup.py", line 234, in test_sensor_post
    self.get_json('/isensors/%s/' %

      File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/tests/api/base.py", line 180, in get_json
    response = self.app.get(full_path,

      File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/webtest/app.py", line 327, in get
    return self.do_request(req, status=status,

      File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/webtest/app.py", line 649, in do_request
    self._check_status(status, res)

      File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/webtest/app.py", line 678, in _check_status
    raise AppError(

    webtest.app.AppError: Bad response: 500 Internal Server Error (not 200 OK or 3xx redirect for http://localhost/v1/isensors/2dce7955-5678-4a2f-ab4f-f0e8bff64a0d/)
b'{"error_message": "{\\"faultcode\\": \\"Server\\", \\"faultstring\\": \\"Instance <SensorsAnalog at 0x7f3bcec312e0> is not bound to a Session; attribute refresh operation cannot proceed (Background on this error at: http://sqlalche.me/e/13/bhk3)\\", \\"debuginfo\\": null}"}'

Captured pythonlogging:
~~~~~~~~~~~~~~~~~~~~~~~
    _host_upgrade_create system version=0.0
None "POST /v1/isensors HTTP/1.0" status: 200 len: 914 time: 0.05324959754943848 POST: {'host_uuid': '1a6b9450-c98c-4219-ae12-d9c3e1cd4cf6', 'datatype': 'analog', 'sensortype': 'testsensortype', 'sensorname': 'testsensorname'} host:localhost:80 agent:None user: None tenant: None domain: None
Server-side error: "Instance <SensorsAnalog at 0x7f3bcec312e0> is not bound to a Session; attribute refresh operation cannot proceed (Background on this error at: http://sqlalche.me/e/13/bhk3)". Detail:
Traceback (most recent call last):

  File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/wsmeext/pecan.py", line 82, in callfunction
    result = f(self, *args, **kwargs)

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/api/controllers/v1/sensor.py", line 358, in get_one
    rpc_sensor = objects.sensor.get_by_uuid(

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/objects/base.py", line 103, in wrapper
    result = fn(cls, context, *args, **kwargs)

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/objects/sensor.py", line 77, in get_by_uuid
    return cls.dbapi.isensor_get(uuid)

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/objects/__init__.py", line 116, in wrapper
    return klass.from_db_object(result)

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/objects/base.py", line 485, in from_db_object
    return cls._from_db_object(cls(), db_obj)

  File "/my/starlingx-master1/cgcs-root/stx/config/sysinv/sysinv/sysinv/sysinv/objects/base.py", line 475, in _from_db_object
    if not hasattr(db_object, field):

  File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/sqlalchemy/orm/attributes.py", line 294, in __get__
    return self.impl.get(instance_state(instance), dict_)

  File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/sqlalchemy/orm/attributes.py", line 725, in get
    value = state._load_expired(state, passive)

  File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/sqlalchemy/orm/state.py", line 652, in _load_expired
    self.manager.deferred_scalar_loader(self, toload)

  File "/tmp/root_sysinvtox/py39/lib/python3.9/site-packages/sqlalchemy/orm/loading.py", line 942, in load_scalar_attributes
    raise orm_exc.DetachedInstanceError(

sqlalchemy.orm.exc.DetachedInstanceError: Instance <SensorsAnalog at 0x7f3bcec312e0> is not bound to a Session; attribute refresh operation cannot proceed (Background on this error at: http://sqlalche.me/e/13/bhk3)

---

Test Activity
-------------
Developer Testing

Workaround
----------
Temporary downgrade SQLAlchemy to 1.2.0(or 1.2.X?) in mock environment.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/root/+/804845

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/root/+/804845
Committed: https://opendev.org/starlingx/root/commit/e7bcb271418a5b308cbd281b5b1f75532a5a5577
Submitter: "Zuul (22348)"
Branch: master

commit e7bcb271418a5b308cbd281b5b1f75532a5a5577
Author: Dan Voiculeasa <email address hidden>
Date: Tue Aug 17 11:16:38 2021 +0000

    Temporary downgrade SQLAlchemy version in mock environments

    Downgrade SQLAlchemy version to allow stx/config/sysinv tests to pass.
    This will allow the zuul gate to pass. This allows py39 tests zuul
    gate for stx/config/sysinv to be successfully set up.

    Story: 2009101
    Task: 42976
    Partial-Bug: 1940281
    Signed-off-by: Dan Voiculeasa <email address hidden>
    Change-Id: Ifd76bff0761554d3c53f46877fecbc4bbcec5ad4