@Test
  public void testTableSplitFollowedByModify() throws Exception {
    final TableName tableName = TableName.valueOf(name.getMethodName());
    TEST_UTIL.createTable(tableName, Bytes.toBytes("f"));

    // get the original table region count
    List<RegionInfo> regions = ADMIN.getRegions(tableName);
    int originalCount = regions.size();
    assertEquals(1, originalCount);

    // split the table and wait until region count increases
    ADMIN.split(tableName, Bytes.toBytes(3));
    TEST_UTIL.waitFor(30000, new Predicate<Exception>() {

      @Override
      public boolean evaluate() throws Exception {
        return ADMIN.getRegions(tableName).size() > originalCount;
      }
    });

    // do some table modification
    TableDescriptor tableDesc = TableDescriptorBuilder.newBuilder(ADMIN.getDescriptor(tableName))
      .setMaxFileSize(11111111).build();
    ADMIN.modifyTable(tableDesc);
    assertEquals(11111111, ADMIN.getDescriptor(tableName).getMaxFileSize());
  }
Do get of RegionInfo from Master using encoded region name.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAdmin2.java