Fix issues in tox run

[chandurup]

• Issue 1 - Tox takes latest version for ‘[pytest-django](https://pytest-django.readthedocs.io/en/latest/changelog.html#v4-5-2-2021-12-07)’. Not compatible with earlier django versions

  ======================================================================================== test session starts =========================================================================================
  platform darwin -- Python 3.5.10, pytest-6.1.2, py-1.11.0, pluggy-0.13.1
  cachedir: .tox/python2.7-django18/.pytest_cache
  django: settings: settings (from env)
  rootdir: /Users/xxx/workspace/django-performance-testing
  plugins: django-4.5.2
  collected 263 items
  
  tests/testapp/tests/test_integrates_with_django_test_client.py EEEE                                                                                                                            [  1%]
  tests/testapp/tests/test_integrates_with_django_testrunner.py EEEEEEEEEE                                                                                                                       [  5%]
  tests/testapp/tests/test_integrates_with_template_rendering.py E                                                                                                                               [  5%]
  tests/testapp/tests/test_query_collector.py EEEEEEEEE                                                                                                                                          [  9%]
  tests/testapp/tests/test_querycount_limits.py EE                                                                                                                                               [  9%]
  tests/testapp/tests/test_worst_report_integrates_with_django_testrunner.py EEEE                                                                                                                [ 11%]
  tests/testapp/tests/test_can_classify_queries_into_read_and_write_other.py EEEEEEEEEEE                                                                                                         [ 15%]
  tests/testapp/tests/test_core_constructing_a_registry.py EEEEEE                                                                                                                                [ 17%]
  tests/testapp/tests/test_core_context.py EEEEEE                                                                                                                                                [ 20%]
  tests/testapp/tests/test_core_infrastructure.py EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE                                                           [ 52%]
  tests/testapp/tests/test_core_settings_based_registry.py EEEEEEE                                     
  
  =============================================================================================== ERRORS ===============================================================================================
  ______________________________________ ERROR at setup of test_can_specify_limits_through_settings_for_django_test_client[GET-4-5-queries-queries-DbQueriesView] ______________________________________
  
  request = <SubRequest 'django_test_environment' for <Function test_can_specify_limits_through_settings_for_django_test_client[GET-4-5-queries-queries-DbQueriesView]>>
  
      @pytest.fixture(autouse=True, scope="session")
      def django_test_environment(request) -> None:
  >           setup_test_environment(debug=debug)
  E           TypeError: setup_test_environment() got an unexpected keyword argument 'debug'

• Issue 2 - Py27 like short names unable to span environments

  ERROR:  py27-django18-pytest3: InterpreterNotFound: python2.7
  ERROR:  py34-django18-pytest3: InterpreterNotFound: python3.4
    py35-django18-pytest3: commands succeeded
  ERROR:  py27-django19-pytest3: InterpreterNotFound: python2.7
  ERROR:  py34-django19-pytest3: InterpreterNotFound: python3.4
    py35-django19-pytest3: commands succeeded
  ERROR:  py27-django110-pytest3: InterpreterNotFound: python2.7
  ERROR:  py34-django110-pytest3: InterpreterNotFound: python3.4

  Cause:

  1. Tox unable to link shorter names to specific python version. Problem could be with underlying virtual-environment (i use pyenv) & how tox maps the shorter environment. Have to explore more on Tox [wip].
  2. Similar issue tox is not creating environment py34 "InterpreterNotFound" tox-dev/tox#378 - but circumvented with longer names like python2.7 for py27.

• Issue 3 - Ambiguous naming - Usage of ‘l’. Flake’s error

  flake8 django_performance_testing tests proof-of-concepts
  tests/testapp/tests/test_core_infrastructure.py:79:13: E741 ambiguous variable name 'l'
  tests/testapp/tests/test_core_infrastructure.py:91:17: E741 ambiguous variable name 'l'
  make: *** [lint] Error 1
  ERROR: InvocationError for command /usr/bin/make test lint docs (exited with code 2)

  Cause:

  • https://www.flake8rules.com/rules/E741.html

    Variables named `I`, `O`, and `l` can be very hard to read. This is because the letter `I` and the letter `l` are easily confused, and the letter `O` and the number `0` can be easily confused.

[zsoldosp]

Thanks for the PR @chandurup ! Looks good, but let me verify this locally - I'm a bit busy at work, but should be able to do so in the next few days.

[zsoldosp]

just an update: I couldn't yet setup my dev env (1) - virtualenv/python has aged too much since the last time this repo was upgraded (2) so I wasn't able to run the tests with your changes

Since the repo needs upgrading anyways, my plan is to find the earliest django / python version where I can get tox to create the envs & run, and then start fixing the code then

---

(1) https://github.com/zsoldosp/django-devmachine
(2) tox -e py3.6-django18 -vv gives

...
py3.6-django18: 208 D get interpreter info via cmd: /bin/python3.6 /home/vagrant/.local/lib/python3.8/site-packages/virtualenv/discovery/py_info.py xrEk7RYqAt54YEHDQg5QTCrpbbIB3i9L 6lZQBRxCHP7NlCxTyjvk6yZkaKkLbS3Q [virtualenv/discovery/cached_py_info.py:111]
py3.6-django18: 232 I failed to query /bin/python3.6 with code 1 err: '  File "/home/vagrant/.local/lib/python3.8/site-packages/virtualenv/discovery/py_info.py", line 7\n    from __future__ import annotations\n    ^\nSyntaxError: future feature annotations is not defined\n' [virtualenv/discovery/cached_py_info.py:34]
...

and I won't even mention the legacy py27 :)