conn.tableOperations().attachIterator("table1", is);
Scanner scanner = conn.createScanner("table1", Constants.NO_AUTHS);
assertEquals(new HashSet<String>(Arrays.asList("2", "3")), getRows(scanner));
scanner.fetchColumn(new Text("cf1"), new Text("cq2"));
assertEquals(new HashSet<String>(Arrays.asList("1", "3")), getRows(scanner));
scanner.clearColumns();
scanner.fetchColumn(new Text("cf1"), new Text("cq1"));
assertEquals(new HashSet<String>(), getRows(scanner));