public void removeColumnFromGroup() {
ColumnGroup columnGroup = model.getColumnGroupByIndex(12);
List<Integer> columnIndexesInGroup = columnGroup.getMembers();
Assert.assertTrue(columnIndexesInGroup.contains(12));
Assert.assertTrue(columnGroup.removeColumn(12));
columnGroup = model.getColumnGroupByIndex(13);
columnIndexesInGroup = columnGroup.getMembers();
Assert.assertEquals(1, columnIndexesInGroup.size());
Assert.assertTrue(columnGroup.removeColumn(13));