@Test
  public void testFilterRegistration() throws Exception {
    Configuration conf = UTIL.getConfiguration();
    conf.set("hbase.thrift.filters", "MyFilter:filterclass");
    ThriftServer.registerFilters(conf);
    Map<String, String> registeredFilters = ParseFilter.getAllFilters();
    assertEquals("filterclass", registeredFilters.get("MyFilter"));
  }
Padding numbers to make comparison of sort order easier in a for loop
@param n   The number to pad.
@param pad The length to pad up to.
@return The padded number as a string.
hbase-thrift/src/test/java/org/apache/hadoop/hbase/thrift2/TestThriftHBaseServiceHandler.java