Per discussion in https://github.com/pypa/cibuildwheel/pull/1169, the default installer used for cp38 is an Intel installer.
It makes sense to skip testing arm64 wheels in this case.
However, if the user choose to manually install the universal2 CPython version, then, tests shall be run on arm64.
This allows users that either target 11.0+ on intel, universal2 or only build for arm64 to get the arm64 wheel tested on AppleSilicon.
test_build_default_launches was using cibuildwheel setup.cfg which led to the test failing once python 3.6 was dropped.
Use an empty package, provided by fake_package_dir, to run the test.
* Add test for defaults, fix platform detection
* Improve correctness of reader.identifier with block
* Fix options test to be multiplatform
* 'Refactored by Sourcery'
docs: write a section on overrides
tests: test docker launches
feat: add identifiers to launches
test: add test for correct build step generation
Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>