Switch test runner from nosetest to pytest

[cognifloyd]

This cherry-picks commits from #6236 from @nzlosh, @FileMagic, and @guzzijones.

This adjust the Makefile and st2-run-pack-tests to use pytest instead of nosetest. We need to switch because nosetest is unmaintained and does not support python 3.10. Goodbye nosetest! 🎉

Several of the tests were adjusted to:

• use pytest.raises instead of assertRaisesRegex, and
• use pytest.mark.skipif instead of unittest.skipIf.

Finally, this drops nose (and plugins) from requirements and regenerates lockfiles/st2.lock. I also copied the updated requirement pins from the lockfile into fixed-requirements.txt and related files.

Lockfile diff: lockfiles/st2.lock [st2]

==                    Upgraded dependencies                     ==

  amqp                           5.2.0        -->   5.3.1
  apscheduler                    3.10.4       -->   3.11.0
  argcomplete                    3.5.1        -->   3.5.2
  async-timeout                  4.0.3        -->   5.0.1
  attrs                          24.2.0       -->   24.3.0
  bcrypt                         4.2.0        -->   4.2.1
  certifi                        2024.8.30    -->   2024.12.14
  ciso8601                       2.3.1        -->   2.3.2
  eventlet                       0.37.0       -->   0.38.2
  orjson                         3.10.10      -->   3.10.12
  packaging                      24.1         -->   24.2
  pip                            24.2         -->   24.3.1
  pyspnego                       0.11.1       -->   0.11.2
  python-json-logger             2.0.7        -->   3.2.1
  redis                          5.2.0        -->   5.2.1
  setuptools                     75.2.0       -->   75.3.0
  six                            1.16.0       -->   1.17.0
  tomli                          2.0.2        -->   2.2.1
  virtualenv                     20.27.0      -->   20.28.0
  werkzeug                       3.0.4        -->   3.0.6
  wheel                          0.44.0       -->   0.45.1
  wrapt                          1.16.0       -->   1.17.0

==                     Removed dependencies                     ==

  colorama                       0.4.6
  nose                           1.3.7
  nose-parallel                  0.4.0
  nose-timer                     1.0.1
  rednose                        1.3.0
  termstyle                      0.1.11

A follow-up PR will cherry-pick changes to finally start testing with python 3.10 +.

[cognifloyd]

Well that's disappointing. I added pytest-shard for Makefile-based pytest runs because doing only one shard made it really slow. But, now there are 2 nonsensical test failures.

Oddly enough pytest-shard shards per test instead of per file, so tests in the same file are split between shards. When pants does test sharding, it does so at the file level.

For the 2 failures, the AttributeError happens in only those 2 tests. The rest of the tests in that file (and in the same unittest class) all pass in both shards even though many of them use the same model and the same attribute.

What could cause this behavior?!

[cognifloyd]

I inlined the pytest-test-group plugin and modified it to shard the files instead of the tests, which is basically what pants does. So, now we aren't getting those weird failures when tests in the same file get run in different shards/chunks.