public void DeleteDirectoryFail()
{
var mountfs = new MountFileSystem();
mountfs.Mount("/dir1", new MemoryFileSystem());
Assert.Throws <UnauthorizedAccessException>(() => mountfs.DeleteDirectory("/dir1", true));
Assert.Throws <UnauthorizedAccessException>(() => mountfs.DeleteDirectory("/dir1", false));
Assert.Throws <DirectoryNotFoundException>(() => mountfs.DeleteDirectory("/dir2", false));
}
