### Question:
Mindex { public Mindex(Path path) throws IOException { this(path, 3); } Mindex(Path path);  Mindex(Path path, int prefetch); long get(int shardToGet);  }### Answer:
@Test public void testMindex() throws IOException { try (FileSystem fs = Jimfs.newFileSystem(Configuration.unix())) { Path mindexPath = fs.getPath("mindex"); ByteBuffer nine = ByteBuffer.allocate(8 * 9); LongBuffer nineLongs = nine.asLongBuffer(); for (int i = 0; i < 9; i++) { nineLongs.put(10 + i); } Files.write(mindexPath, nine.array(), StandardOpenOption.WRITE, StandardOpenOption.CREATE); Mindex mindex = new Mindex(mindexPath); for (int i = 0; i < 9; i++) { assertThat(mindex.get(i)).isEqualTo(10 + i); } for (int i = 8; i >= 0; i--) { assertThat(mindex.get(i)).isEqualTo(10 + i); } } }