@Test
public void registerFileSystems() {

    final Configuration conf = new Configuration(false);
    FileSystemUtil.registerFileSystems(Arrays.asList(new LocalFileSystem(), new MockFileSystem(), new RawLocalFileSystem()), conf);
    Assert.assertEquals(LocalFileSystem.class.getName(), conf.get("fs.file.impl"));
    Assert.assertEquals(MockFileSystem.class.getName(), conf.get("fs.mock.impl"));
}