private Cell newCellWithNotExistColumnFamily(Cell cell) {
      return ExtendedCellBuilderFactory.create(CellBuilderType.SHALLOW_COPY)
        .setRow(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength())
        .setFamily(CF_NOT_EXIST_BYTES, 0, CF_NOT_EXIST_BYTES.length)
        .setQualifier(CellUtil.cloneQualifier(cell)).setTimestamp(cell.getTimestamp())
        .setType(cell.getType().getCode()).setValue(CellUtil.cloneValue(cell)).build();
    }
Test coprocessor methods
{@link RegionObserver#postIncrementBeforeWAL(ObserverContext, Mutation, List)} and
{@link RegionObserver#postAppendBeforeWAL(ObserverContext, Mutation, List)}. These methods may
change the cells which will be applied to memstore and WAL. So add unit test for the case which
change the cell's column family and tags.
hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestPostIncrementAndAppendBeforeWAL.java