### Question:
DLFileSystem extends FileSystem { @Override public boolean mkdirs(Path path, FsPermission fsPermission) throws IOException { String streamName = getStreamName(path); namespace.createLog(streamName); return true; } DLFileSystem(); @Override URI getUri(); @Override void initialize(URI name, Configuration conf); @Override void close(); @Override Path getHomeDirectory(); @Override void setWorkingDirectory(Path path); @Override Path getWorkingDirectory(); @Override FSDataInputStream open(Path path, int bufferSize); @Override FSDataOutputStream create(Path path,
                                     FsPermission fsPermission,
                                     boolean overwrite,
                                     int bufferSize,
                                     short replication,
                                     long blockSize,
                                     Progressable progressable); @Override FSDataOutputStream append(Path path,
                                     int bufferSize,
                                     Progressable progressable); @Override boolean delete(Path path, boolean recursive); @Override FileStatus[] listStatus(Path path); @Override boolean mkdirs(Path path, FsPermission fsPermission); @Override FileStatus getFileStatus(Path path); @Override boolean rename(Path src, Path dst); @Override boolean truncate(Path f, long newLength); static final String DLFS_CONF_FILE; }### Answer:
@Test public void testMkDirs() throws Exception { Path path = new Path("/path/to/" + runtime.getMethodName()); assertFalse(fs.exists(path)); assertTrue(fs.mkdirs(path)); assertTrue(fs.exists(path)); assertTrue(fs.mkdirs(path)); }