This makes blockbuster an actually optional test dependency, as suggested in cbornet/blockbuster#46 (comment), assuming the skip_blockbuster mark is set when the dependency is unavailable.

What do these changes do?

Only import the blockbuster module inside the blockbuster fixture, rather than at the top level of tests/conftest.py, and even then, only after we have ruled out the cases in which it would not actually be used.

The result is that the blockbuster module is never imported at all when the skip_blockbuster mark is set; before, it was unconditionally imported no matter what, so it wasn’t really an optional test dependency in practice.

This is useful in Fedora, where we package python-aiohttp but we would rather avoid packaging python-blockbuster and its dependency python-forbiddenfruit if possible – see cbornet/blockbuster#46 for context. It is likely to be useful for other distribution packagers as well.

Are there changes in behavior for the user?

No, only for people running the tests under certain conditions.

Is it a substantial burden for the maintainers to support this?

It should be no burden at all.

Related issue number

N/A

Checklist

• I think the code is well written
• Unit tests for the changes exist N/A, the change is in test code
• Documentation reflects the changes No documentation changes are required
• If you provide code modification, please add yourself to CONTRIBUTORS.txt

• Add a new news fragment into the CHANGES/ folder