fix: Add tests for accepting #[cfg(..)]

[skogseth]

This adds some tests verifying that we accept #[cfg(..)] together with the #[test] macro.

Fixes #141

[coveralls]

Pull Request Test Coverage Report for Build 18934252348

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 30.588%

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Totals
Change from base Build 18922077486:	0.0%
Covered Lines:	505
Relevant Lines:	1651

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💛 - Coveralls

[skogseth]

This should close #141, but #140 is still an option for the future.

[epage]

We'll also need tests that verify this.

Probably the safest is a #[cfg(any())] and a #[cfg(all())] test

[epage]

Feel free to clean up commits for how this should be reviewed.

It also looks like #144 introduced conflicts