private Collection<RecoveringBlock> initRecoveringBlocks() throws IOException {
Collection<RecoveringBlock> blocks = new ArrayList<RecoveringBlock>(1);
DatanodeInfo[] locs = new DatanodeInfo[] {
new DatanodeInfo(dn.getDNRegistrationForBP(block.getBlockPoolId())),
mock(DatanodeInfo.class) };
RecoveringBlock rBlock = new RecoveringBlock(block, locs, RECOVERY_ID);
blocks.add(rBlock);
return blocks;
}