Snapshot files should be resolved relative from the file, not from cwd

[mcollina]

In a npm workspace project, I would like to:

1. have the snapshots stored in the root of the module
2. to run my tests from the root of the repository as well as the root of the module

I could not find a way to set it up. I thought to do it with snapshotFile but the snapshot entries are created with a packages/mymodule prefix added depending on my cwd(). I tracked it down to

libtap/lib/test.js

Lines 1199 to 1205 in 7d2934a

	get fullname () {
	const main = process.argv.slice(1).join(' ').trim()
	return (this.parent ? this.parent.fullname
	: main.indexOf(cwd) === 0 ? main.substr(cwd.length + 1)
	: path.basename(main)).replace(/\\/g, '/') +
	' ' + (this.name || '').trim()
	}

.

The fullname of a test is created from cwd().

I'm currently fixing this with:

Object.defineProperty(t, 'fullname', {
  value: 'mymodule/mytest'
})

I can work on a PR but I would need some direction. I see two possible fixes:

1. make the test.fullname not dependent from cwd()
2. make the snapshot file not use the fullname for the internal entries

Wdyt?