Usually, we don't accept PRs that are only cosmetic, especially in tests. So I won't approve this one, sorry. We can clean it up if we were to rewritetest_decimal to remove duplicated code. For instance, all test methods do:

getcontext = self.decimal.getcontextlocalcontext = self.decimal.localcontext

To save a few keystrokes. In this case, why not having a method for that on the test class itself.

Now, I would be more interested in reorganizing this test file because it's 6 THOUSANDS lines...

Usually, we don't accept PRs that are only cosmetic, especially in tests. So I won't approve this one, sorry.

Ok, no problems.

Now, I would be more interested in reorganizing this test file because it's 6 THOUSANDS lines...

I agree, that's a lot of code.

I've tried to make this reorganization.
But there's a problem with command line arguments of this test.
If we splitLib/test/test_decimal.py and make package directoryLib/test/test_decimal, then we should rununittest.main in__main__.py. But there's used kinda hack, with setting global value ofARITH beforeunittest.main. And this doesn't work in case of different files.

Maybe you have some idea on that topic?
Do we really want to keep--debug and--skip flags here or we can remove them?

then we should rununittest.main in__main__.py. But there's used kinda hack, with setting global value ofARITH

Ithink it's fine. We already do this fortest_asyncio.

We already do this fortest_asyncio.

Could you please guide me a little?
Link to some PR or commit would be great.

Could you please guide me a little?

FTR, this was just for the__main__.py question, not about the CLI itself. InLib/test/test_asyncio you can see that there is a__main__.py file that contains

from .importload_testsimportunittestunittest.main()

and in__init__.py there is a function that configure the tests. Instead of global variables, we can have a base class with class variables that would then be configured to be skipped or not depending on the CLI args.

I don't really know whether it's possible to do it though. Maybe it's not! However, I think we should discuss this either on Discord or create an issue for that (at least this PR shouldn't be used for discussion).