@Override
    public Admin getAdmin() throws IOException {
      Admin admin = Mockito.mock(Admin.class);
      Mockito.when(admin.getConfiguration()).thenReturn(getConfiguration());
      return admin;
    }
Connection to use above in Test.
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/mapreduce/TestMultiTableInputFormatBase.java