Files are erroneously ignored if process.cwd() contains symlinks

[motiz88]

1. babel-plugin-istanbul preprocesses paths with realpath() before filtering them with test-exclude.
2. test-exclude excludes paths that are outside of process.cwd().

When process.cwd() includes symlinks, the use of realpath() means that all files will appear to be outside of the working directory.

Possible solutions:

A) Resolve process.cwd() with realpath() too

(PR #8 does this)

    exclude = testExclude({
      cwd: getRealpath(process.cwd()),
//...

Or alternatively:

B) Don't use realpath() on any files at all

There may, of course, be a good reason to keep using realpath() that I'm not aware of.

[motiz88]

@bcoe I am seeing a regression to the old behavior due to the use of non-realpath-normalized NYC_CWD since fabb602. This issue should probably be reopened.

[motiz88]

@bcoe? Anyone?

[bcoe]

@motiz88 mind submitting a failing unit-test, I'm not quite sure how to reproduce this failing behavior.

[motiz88]

I'll keep thinking about a way to put this in a unit test. Here are the repro steps:

1. Start with a project that is set up to use babel-plugin-istanbul and is generating coverage.
2. Create a symlink to the project root, from elsewhere in the file system (Linux ln or Windows mklink)
3. In a terminal, cd to the project via the symlink.
4. Try to generate coverage. All source files will be ignored.