add: handle edge cases & tests for macos

[swarnimarun]

Tests currently would only run on macos, but since we don't have a CI it shouldn't be an issue, when we add a CI we should support linux and other platforms as well for these tests.

[swarnimarun]

@biswaroop1547 r?

[biswaroop1547]

lgtm! also works for previously failing case i.e:

{"aarch64-apple-darwin": None, "universal-apple-darwin": Some("xyz.com"), "x86_64-apple-darwin": None}

[swarnimarun]

@tiero merge?

[tiero]

utACK 65b7ebf