@Test
public void listDirectories() throws IOException {

	final String sign = "file_dir";
	FilePath folderWrite = new FilePath(new Path(folder.getRoot().toPath().toString(), sign));
	FilePath fileWrite = new FilePath(new Path(folder.getRoot().toPath().toString(), "1"), folderWrite.getFileSystem());
	folderWrite.getFileSystem().mkdirs(folderWrite.getPathStr());
	writeFile(fileWrite, sign);
	Assert.assertEquals(1, folderWrite.getFileSystem().listDirectories(folder.getRoot().toPath().toString()).size());
}