Enable subprocess test coverage gathering

[zsimic]

This catches ~10 more lines covered

[coveralls]

Pull Request Test Coverage Report for Build 23274217369

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 98.476%

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Totals
Change from base Build 23273021032:	0.3%
Covered Lines:	2649
Relevant Lines:	2690

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💛 - Coveralls

[thatch]

I'm a fly on the wall to know if this is better than the defaults -- I thought the .pth handled patching for us now.

[nedbat]

You do need patch = subprocess for the .pth to have an effect. I was conservative and didn't want it being enabled automatically.