private static void waitForServerCommissioned(ServerName excludeServer,
    boolean anyServerDecommissioned) {
    TEST_UTIL.waitFor(3000, () -> {
      try {
        List<ServerName> decomServers = TEST_UTIL.getAdmin().listDecommissionedRegionServers();
        if (anyServerDecommissioned) {
          return decomServers.size() == 1 && decomServers.get(0).equals(excludeServer);
        } else {
          return decomServers.size() == 0;
        }
      } catch (IOException e) {
        throw new RuntimeException(e);
      }
    });
  }
Do get of RegionInfo from Master using encoded region name.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAdmin2.java