Fix issue #498 - c8 CLI doesn't work properly when executed in a sub-directory of the project

[ericmorand]

This PR fixes the issue #498...and also change the philosophy of c8.

The fix

This PR makes c8 consider the include and exclude patterns as relative to the configuration file location, if any, or the current working directory, otherwise. By applying such a change, c8 can be executed from any subdirectory of the project and will always resolve sources to include and exclude regardless of the current working directory, if a configuration file is present.

The philosophy shift

c8 philosophy seems to have been heavily inspired by nyc, which means that it inherits from nyc debatable (and arguably archaic) design decisions. These decisions can be summarized this way:

Options src, include, exclude, extension, excludeNodeModules, allowExternal and all are overlapping and can be reduced to only include and exclude without removing any feature.

This PR removes all the mentioned options except include and exclude, and updates the logic so that all the removed options are organically available through the include and exclude options.

Let's see how it goes.

--src

This option is overlapping with the include option, which is the declaration of the files that we want to be covered by the tests:

--include=src/main/**/*.js

--extension

This option is overlapping with the include option, which is the declaration of the files that we want to be covered by the tests:

--include=src/main/**/*.ts --include=src/main/**/*.tsx

Or:

--include=src/main/**/*.{ts,tsx}

--allowExternal

This option is overlapping with the include option, which is the declaration of the files that we want to be covered by the tests:

--include=src/main/**/*.ts --include=../../../../external-project/*.js

--excludeNodeModules

This option is overlapping with the exclude option, which is the declaration of the files that we don't want to be covered by the tests:

--include=**/*.js --exclude=node_modules/**/*

--all

This option is overlapping with the include and exclude options, would we want to not include all of them, it is possible through a combination of include and exclude:

--include=**/*.js --exclude=**/not-included/*.js

This is obviously a breaking change.

[bcoe]

I'm concerned about removing so many tests in this PR.

[bcoe]

@ericmorand I understand where you're coming from, but this breaking change would be pretty drastic, and I don't have the time to put into open source these days to support it.

Could we instead figure out how to make --allowExternal work for your case, and fix any bugs you bump into.

[ericmorand]

@bcoe , your point is fair and I actually agree that this is too much of a drastic change, even for a breaking change: this is like a different product. I'll probably end up proposing a dedicated package - heavily inspired by your great work. I think we can close this PR.