Tests broken on Windows: "even with special characters"

While inspecting for a bug, I tried running the tests. These errors happens on both `cmd` and `cygwin`, with Node.js **4.2.1** on Windows 8.1. `D:\Project\` has no particular rights.

```
D:\Project\node_modules\mv> npm t

> mv@2.1.1 test D:\Project\node_modules\mv
> mocha test/test.js --reporter spec

mv
√ should rename a file on the same device
√ should not overwrite if clobber = false
√ should not create directory structure by default
√ should create directory structure when mkdirp option set
√ should work across devices (38ms)
1) should work across devices, even with special characters
√ should move folders (56ms)
√ should move folders across devices (45ms)
2) should move folders across devices, even with special characters

7 passing (342ms)
2 failing

1) mv should work across devices, even with special characters:
Uncaught Error: ENOENT: no such file or directory, open 'D:\Project\node_modules\mv\test\a-*'
at Error (native)

2) mv should move folders across devices, even with special characters:
Uncaught Error: ENOENT: no such file or directory, open 'D:\Project\node_modules\mv\test\a-*'
at Error (native)

npm ERR! Test failed. See above for more details.
```