Only override process.binding('fs')

[tschaub]

This reworks how the fs module is mocked. Instead of overriding methods on the module itself, only the process.binding('fs') methods are replaced.

Possible breaking changes:

• The mock.fs() function has been removed (this could be added back)
• The object created by fs.Stats is no longer an instanceof fs.Stats (this could be possible to support again)
• Lazy require() calls don't work consistently (perhaps this can be made to work again too)
• No more support for Node < 4 (tests are not run there, but things probably still work)

[not-an-aardvark]

Wow, this looks like a very nice simplification if it works.

It's probably worth noting that process.binding('fs') isn't officially a stable Node feature; it's possible that the binding will unexpectedly change in the future, or do something different between major Node versions. But it looks like you already have a lib/binding.js file, so I suppose that problem isn't newly introduced by this change.

[eugef]

I am using Node 6.3 and Babel to transpile import statements.
The current master doesn't work for me.

But this PR works for me, great job @tschaub !

Any plans to release it?

[tschaub]

@not-an-aardvark - Yeah, I'm aware that process.binding('fs') is not a stable feature. It turns out that the mock-fs binding works with Node 0.8 through 7. So although there have been Node releases with breaking fs changes, I've been able to maintain a single binding that has worked with them all.

@eugef - I haven't had time to address the breaking changes mentioned above. I'm personally most interested in fixing the require issue (making require consistently work with the real fs even when called lazily). Not sure which of these will affect the most users.

I'll release a beta and see if we can get some feedback.

[eugef]

When it would be released?

[tschaub]

You can install mock-fs@beta to try it out.