Make the test coverage blackbox less magical

[caspervonb]

Currently the coverage blackbox is a bit magical in that it checks if an executed script is next to any of the test modules that ran; if it is then it is included in the report.

This works out pretty well for std like modules where the test module is next to the module, but if you want to coverage for something that is elsewhere there is no way to do that.

This issue came up quite a bit on discord where people are using folders for tests.

So, a much, much simpler approach to this is just to make the coverage option an Option<String> which defaults to cwd and test if a module url starts with that value.

Test modules would still be excluded.

WDYT?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.