[FR] Extend the default tests glob inclusion

What's the problem this feature will solve?

The docs @ https://setuptools.pypa.io/en/latest/userguide/miscellaneous.html#controlling-files-in-the-distribution say:

• Files that match the following glob patterns: tests/test*.py, test/test*.py;

Test files that have _test suffix in their base name are not included automatically. This is one of the common naming conventions. They should.

Describe the solution you'd like

Including test files that have _test suffix in base name would be super useful. Additionally, does this recognize well-known names like conftest.py?

Alternative Solutions

No response

Additional context

The example is a pyproject.toml looking as follows:

[build-system]
requires = [
  "setuptools",
]
build-backend = "setuptools.build_meta"

[project]
name = "lokiverse"
version = "1.0.0"
dependencies = [
  "cheroot",
]

The project has an src/ layout with top-level tests/ and the file at tests/api_test.py is not included.

Code of Conduct

• I agree to follow the PSF Code of Conduct

Start with the documentation section on controlling files in the distribution and reproduce the reported src-layout case using the shown pyproject.toml and tests/api_test.py. Check how the default test-file globs handle the existing test*.py patterns, _test suffixes, and conftest.py. Done means the intended files are included automatically and the documentation accurately describes the behavior.