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));
scanner.setRange(new Range("0", "4"));
scanner.clearColumns();