	@Test
	public void testMaxFileNumber() throws IOException {

		File file0 = new File(testDir, "/puma/20151010/bucket-0.data");
		createFile(file0);

		File file1 = new File(testDir, "/puma/20151010/bucket-1.data");
		createFile(file1);

		File file2 = new File(testDir, "/puma/20151010/bucket-10.data");
		createFile(file2);

		File file3 = new File(testDir, "/puma/20151010/bucket-7.data");
		createFile(file3);

		assertEquals(10, FileSystem.maxFileNumber(testDir.getAbsolutePath(), "puma", "20151010", "bucket-", ".data"));
	}