Support .coverage.host.number.number

[mandjevant]

Please go over all the sections and search https://pytest-cov.readthedocs.io/en/latest/ or https://coverage.readthedocs.io/en/latest/ before opening the issue.

Summary

I'm configuring pytest on my existing repository with 130 tests. All tests make use of multiprocessing. Simple Process and Pipe where I am joining the Process.

During tests, thousands of .coverage.host.number.number files are created.

Expected vs actual result

Actual result: A simple test pytest --cov project tests/test_file (with two test cases) produces 40 .coverage files. When all tests are finished, the files are merged into a single .coverage file.

Scaling this to 130 tests yields thousands of .coverage.host.number.number files. This has a significant effect on the execution time of the tests.

Expected result: A reasonable amount of temporary .coverage.host.number.number files.

Versions

pytest 7.0.0 pytest-cov 3.0.0 coverage 6.2

Also tested coverage 6.3.1

Issue

I expect I am misusing pytest (while I'm following all subprocess guidelines in the docs). Or what happens is normal but my expectations are different. I'd like some advice on this.