I've just found some inconsistency in File::isDirectory() implementations.
The documentation says:
Checks whether the file is a directory that exists [...] returns true only if the file is a directory which actually exists, so false if it's a file or doesn't exist at all.
So I assume that File::nonexistent.isDirectory() should return false because "it doesn't exist at all".
In fact on Windows it returns false but on Mac it returns true. Shouldn't we get the same results?