private String assertHasOneMobRow(Table table, TableName tn, String familyName)
    throws IOException {
    Scan scan = new Scan();
    scan.setAttribute(MobConstants.MOB_SCAN_RAW, Bytes.toBytes(Boolean.TRUE));
    ResultScanner rs = table.getScanner(scan);
    Result r = rs.next();
    Assert.assertNotNull(r);
    String fileName = MobUtils.getMobFileName(r.getColumnLatestCell(FAMILY, QF));
    Path filePath =
      new Path(MobUtils.getMobFamilyPath(TEST_UTIL.getConfiguration(), tn, familyName), fileName);
    FileSystem fs = TEST_UTIL.getTestFileSystem();
    Assert.assertTrue(fs.exists(filePath));
    r = rs.next();
    Assert.assertNull(r);
    return fileName;
  }
Generate the mob value. the size of the value
@return the mob value generated
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestDeleteMobTable.java