diff --git a/src/miner.cpp b/src/miner.cpp
index dade8a9d77..acb1f9cb10 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -1,687 +1,691 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "miner.h"
 
 #include "amount.h"
 #include "chain.h"
 #include "chainparams.h"
 #include "coins.h"
 #include "config.h"
 #include "consensus/consensus.h"
 #include "consensus/merkle.h"
 #include "consensus/validation.h"
 #include "hash.h"
 #include "net.h"
 #include "policy/policy.h"
 #include "pow.h"
 #include "primitives/transaction.h"
 #include "script/standard.h"
 #include "timedata.h"
 #include "txmempool.h"
 #include "util.h"
 #include "utilmoneystr.h"
 #include "validation.h"
 #include "validationinterface.h"
 
 #include <algorithm>
 #include <queue>
 #include <utility>
 
 #include <boost/thread.hpp>
 #include <boost/tuple/tuple.hpp>
 
 static const int MAX_COINBASE_SCRIPTSIG_SIZE = 100;
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // BitcoinMiner
 //
 
 //
 // Unconfirmed transactions in the memory pool often depend on other
 // transactions in the memory pool. When we select transactions from the
 // pool, we select by highest priority or fee rate, so we might consider
 // transactions that depend on transactions that aren't yet in the block.
 
 uint64_t nLastBlockTx = 0;
 uint64_t nLastBlockSize = 0;
 
 int64_t UpdateTime(CBlockHeader *pblock, const Config &config,
                    const CBlockIndex *pindexPrev) {
     int64_t nOldTime = pblock->nTime;
     int64_t nNewTime =
         std::max(pindexPrev->GetMedianTimePast() + 1, GetAdjustedTime());
 
     if (nOldTime < nNewTime) {
         pblock->nTime = nNewTime;
     }
 
     const Consensus::Params &consensusParams =
         config.GetChainParams().GetConsensus();
 
     // Updating time can change work required on testnet:
     if (consensusParams.fPowAllowMinDifficultyBlocks) {
         pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, config);
     }
 
     return nNewTime - nOldTime;
 }
 
 static uint64_t ComputeMaxGeneratedBlockSize(const Config &config,
                                              const CBlockIndex *pindexPrev) {
     // Block resource limits
     // If -blockmaxsize is not given, limit to DEFAULT_MAX_GENERATED_BLOCK_SIZE
     // If only one is given, only restrict the specified resource.
     // If both are given, restrict both.
     uint64_t nMaxGeneratedBlockSize = DEFAULT_MAX_GENERATED_BLOCK_SIZE;
     if (gArgs.IsArgSet("-blockmaxsize")) {
         nMaxGeneratedBlockSize =
             gArgs.GetArg("-blockmaxsize", DEFAULT_MAX_GENERATED_BLOCK_SIZE);
     }
 
     // Limit size to between 1K and MaxBlockSize-1K for sanity:
     nMaxGeneratedBlockSize =
         std::max(uint64_t(1000), std::min(config.GetMaxBlockSize() - 1000,
                                           nMaxGeneratedBlockSize));
 
     return nMaxGeneratedBlockSize;
 }
 
 BlockAssembler::BlockAssembler(const Config &_config) : config(&_config) {
 
     if (gArgs.IsArgSet("-blockmintxfee")) {
         Amount n(0);
         ParseMoney(gArgs.GetArg("-blockmintxfee", ""), n);
         blockMinFeeRate = CFeeRate(n);
     } else {
         blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);
     }
 
     LOCK(cs_main);
     nMaxGeneratedBlockSize =
         ComputeMaxGeneratedBlockSize(*config, chainActive.Tip());
 }
 
 void BlockAssembler::resetBlock() {
     inBlock.clear();
 
     // Reserve space for coinbase tx.
     nBlockSize = 1000;
     nBlockSigOps = 100;
 
     // These counters do not include coinbase tx.
     nBlockTx = 0;
     nFees = Amount(0);
 
     lastFewTxs = 0;
-    blockFinished = false;
 }
 
 static const std::vector<uint8_t>
 getExcessiveBlockSizeSig(const Config &config) {
     std::string cbmsg = "/EB" + getSubVersionEB(config.GetMaxBlockSize()) + "/";
     const char *cbcstr = cbmsg.c_str();
     std::vector<uint8_t> vec(cbcstr, cbcstr + cbmsg.size());
     return vec;
 }
 
 std::unique_ptr<CBlockTemplate>
 BlockAssembler::CreateNewBlock(const CScript &scriptPubKeyIn) {
     int64_t nTimeStart = GetTimeMicros();
 
     resetBlock();
 
     pblocktemplate.reset(new CBlockTemplate());
     if (!pblocktemplate.get()) {
         return nullptr;
     }
 
     // Pointer for convenience.
     pblock = &pblocktemplate->block;
 
     // Add dummy coinbase tx as first transaction.
     pblock->vtx.emplace_back();
     // updated at end
     pblocktemplate->vTxFees.push_back(Amount(-1));
     // updated at end
     pblocktemplate->vTxSigOpsCount.push_back(-1);
 
     LOCK2(cs_main, mempool.cs);
     CBlockIndex *pindexPrev = chainActive.Tip();
     nHeight = pindexPrev->nHeight + 1;
 
     const CChainParams &chainparams = config->GetChainParams();
     pblock->nVersion =
         ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
     // -regtest only: allow overriding block.nVersion with
     // -blockversion=N to test forking scenarios
     if (chainparams.MineBlocksOnDemand()) {
         pblock->nVersion = gArgs.GetArg("-blockversion", pblock->nVersion);
     }
 
     pblock->nTime = GetAdjustedTime();
     nMaxGeneratedBlockSize = ComputeMaxGeneratedBlockSize(*config, pindexPrev);
 
     nLockTimeCutoff =
         (STANDARD_LOCKTIME_VERIFY_FLAGS & LOCKTIME_MEDIAN_TIME_PAST)
             ? pindexPrev->GetMedianTimePast()
             : pblock->GetBlockTime();
 
     addPriorityTxs();
     int nPackagesSelected = 0;
     int nDescendantsUpdated = 0;
     addPackageTxs(nPackagesSelected, nDescendantsUpdated);
 
     if (IsMagneticAnomalyEnabled(*config, pindexPrev)) {
         // If magnetic anomaly is enabled, we make sure transaction are
         // canonically ordered.
         std::sort(std::begin(pblock->vtx) + 1, std::end(pblock->vtx),
                   [](const std::shared_ptr<const CTransaction> &a,
                      const std::shared_ptr<const CTransaction> &b) -> bool {
                       return a->GetId() > b->GetId();
                   });
     }
 
     int64_t nTime1 = GetTimeMicros();
 
     nLastBlockTx = nBlockTx;
     nLastBlockSize = nBlockSize;
 
     // Create coinbase transaction.
     CMutableTransaction coinbaseTx;
     coinbaseTx.vin.resize(1);
     coinbaseTx.vin[0].prevout = COutPoint();
     coinbaseTx.vout.resize(1);
     coinbaseTx.vout[0].scriptPubKey = scriptPubKeyIn;
     coinbaseTx.vout[0].nValue =
         nFees + GetBlockSubsidy(nHeight, chainparams.GetConsensus());
     coinbaseTx.vin[0].scriptSig = CScript() << nHeight << OP_0;
     pblock->vtx[0] = MakeTransactionRef(coinbaseTx);
     pblocktemplate->vTxFees[0] = -1 * nFees;
 
     uint64_t nSerializeSize =
         GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION);
 
     LogPrintf("CreateNewBlock(): total size: %u txs: %u fees: %ld sigops %d\n",
               nSerializeSize, nBlockTx, nFees, nBlockSigOps);
 
     // Fill in header.
     pblock->hashPrevBlock = pindexPrev->GetBlockHash();
     UpdateTime(pblock, *config, pindexPrev);
     pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, *config);
     pblock->nNonce = 0;
     pblocktemplate->vTxSigOpsCount[0] =
         GetSigOpCountWithoutP2SH(*pblock->vtx[0]);
 
     CValidationState state;
     BlockValidationOptions validationOptions(false, false);
     if (!TestBlockValidity(*config, state, *pblock, pindexPrev,
                            validationOptions)) {
         throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s",
                                            __func__,
                                            FormatStateMessage(state)));
     }
     int64_t nTime2 = GetTimeMicros();
 
     LogPrint(
         BCLog::BENCH, "CreateNewBlock() packages: %.2fms (%d packages, %d "
                       "updated descendants), validity: %.2fms (total %.2fms)\n",
         0.001 * (nTime1 - nTimeStart), nPackagesSelected, nDescendantsUpdated,
         0.001 * (nTime2 - nTime1), 0.001 * (nTime2 - nTimeStart));
 
     return std::move(pblocktemplate);
 }
 
 bool BlockAssembler::isStillDependent(CTxMemPool::txiter iter) {
     for (CTxMemPool::txiter parent : mempool.GetMemPoolParents(iter)) {
         if (!inBlock.count(parent)) {
             return true;
         }
     }
     return false;
 }
 
 void BlockAssembler::onlyUnconfirmed(CTxMemPool::setEntries &testSet) {
     for (CTxMemPool::setEntries::iterator iit = testSet.begin();
          iit != testSet.end();) {
         // Only test txs not already in the block.
         if (inBlock.count(*iit)) {
             testSet.erase(iit++);
         } else {
             iit++;
         }
     }
 }
 
 bool BlockAssembler::TestPackage(uint64_t packageSize, int64_t packageSigOps) {
     auto blockSizeWithPackage = nBlockSize + packageSize;
     if (blockSizeWithPackage >= nMaxGeneratedBlockSize) {
         return false;
     }
 
     if (nBlockSigOps + packageSigOps >=
         GetMaxBlockSigOpsCount(blockSizeWithPackage)) {
         return false;
     }
 
     return true;
 }
 
 /**
  * Perform transaction-level checks before adding to block:
  * - Transaction finality (locktime)
  * - Serialized size (in case -blockmaxsize is in use)
  */
 bool BlockAssembler::TestPackageTransactions(
     const CTxMemPool::setEntries &package) {
     uint64_t nPotentialBlockSize = nBlockSize;
     for (const CTxMemPool::txiter it : package) {
         CValidationState state;
         if (!ContextualCheckTransaction(*config, it->GetTx(), state, nHeight,
                                         nLockTimeCutoff)) {
             return false;
         }
 
         uint64_t nTxSize =
             ::GetSerializeSize(it->GetTx(), SER_NETWORK, PROTOCOL_VERSION);
         if (nPotentialBlockSize + nTxSize >= nMaxGeneratedBlockSize) {
             return false;
         }
 
         nPotentialBlockSize += nTxSize;
     }
 
     return true;
 }
 
-bool BlockAssembler::TestForBlock(CTxMemPool::txiter it) {
+BlockAssembler::TestForBlockResult
+BlockAssembler::TestForBlock(CTxMemPool::txiter it) {
     auto blockSizeWithTx =
         nBlockSize +
         ::GetSerializeSize(it->GetTx(), SER_NETWORK, PROTOCOL_VERSION);
     if (blockSizeWithTx >= nMaxGeneratedBlockSize) {
         if (nBlockSize > nMaxGeneratedBlockSize - 100 || lastFewTxs > 50) {
-            blockFinished = true;
-            return false;
+            return TestForBlockResult::BlockFinished;
         }
 
         if (nBlockSize > nMaxGeneratedBlockSize - 1000) {
             lastFewTxs++;
         }
 
-        return false;
+        return TestForBlockResult::TXCantFit;
     }
 
     auto maxBlockSigOps = GetMaxBlockSigOpsCount(blockSizeWithTx);
     if (nBlockSigOps + it->GetSigOpCount() >= maxBlockSigOps) {
         // If the block has room for no more sig ops then flag that the block is
         // finished.
         // TODO: We should consider adding another transaction that isn't very
         // dense in sigops instead of bailing out so easily.
         if (nBlockSigOps > maxBlockSigOps - 2) {
-            blockFinished = true;
-            return false;
+            return TestForBlockResult::BlockFinished;
         }
 
         // Otherwise attempt to find another tx with fewer sigops to put in the
         // block.
-        return false;
+        return TestForBlockResult::TXCantFit;
     }
 
     // Must check that lock times are still valid. This can be removed once MTP
     // is always enforced as long as reorgs keep the mempool consistent.
     CValidationState state;
     if (!ContextualCheckTransaction(*config, it->GetTx(), state, nHeight,
                                     nLockTimeCutoff)) {
-        return false;
+        return TestForBlockResult::TXCantFit;
     }
 
-    return true;
+    return TestForBlockResult::TXFits;
 }
 
 void BlockAssembler::AddToBlock(CTxMemPool::txiter iter) {
     pblock->vtx.emplace_back(iter->GetSharedTx());
     pblocktemplate->vTxFees.push_back(iter->GetFee());
     pblocktemplate->vTxSigOpsCount.push_back(iter->GetSigOpCount());
     nBlockSize += iter->GetTxSize();
     ++nBlockTx;
     nBlockSigOps += iter->GetSigOpCount();
     nFees += iter->GetFee();
     inBlock.insert(iter);
 
     bool fPrintPriority =
         gArgs.GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
     if (fPrintPriority) {
         double dPriority = iter->GetPriority(nHeight);
         Amount dummy;
         mempool.ApplyDeltas(iter->GetTx().GetId(), dPriority, dummy);
         LogPrintf(
             "priority %.1f fee %s txid %s\n", dPriority,
             CFeeRate(iter->GetModifiedFee(), iter->GetTxSize()).ToString(),
             iter->GetTx().GetId().ToString());
     }
 }
 
 int BlockAssembler::UpdatePackagesForAdded(
     const CTxMemPool::setEntries &alreadyAdded,
     indexed_modified_transaction_set &mapModifiedTx) {
     int nDescendantsUpdated = 0;
     for (const CTxMemPool::txiter it : alreadyAdded) {
         CTxMemPool::setEntries descendants;
         mempool.CalculateDescendants(it, descendants);
         // Insert all descendants (not yet in block) into the modified set.
         for (CTxMemPool::txiter desc : descendants) {
             if (alreadyAdded.count(desc)) {
                 continue;
             }
 
             ++nDescendantsUpdated;
             modtxiter mit = mapModifiedTx.find(desc);
             if (mit == mapModifiedTx.end()) {
                 CTxMemPoolModifiedEntry modEntry(desc);
                 modEntry.nSizeWithAncestors -= it->GetTxSize();
                 modEntry.nModFeesWithAncestors -= it->GetModifiedFee();
                 modEntry.nSigOpCountWithAncestors -= it->GetSigOpCount();
                 mapModifiedTx.insert(modEntry);
             } else {
                 mapModifiedTx.modify(mit, update_for_parent_inclusion(it));
             }
         }
     }
 
     return nDescendantsUpdated;
 }
 
 // Skip entries in mapTx that are already in a block or are present in
 // mapModifiedTx (which implies that the mapTx ancestor state is stale due to
 // ancestor inclusion in the block). Also skip transactions that we've already
 // failed to add. This can happen if we consider a transaction in mapModifiedTx
 // and it fails: we can then potentially consider it again while walking mapTx.
 // It's currently guaranteed to fail again, but as a belt-and-suspenders check
 // we put it in failedTx and avoid re-evaluation, since the re-evaluation would
 // be using cached size/sigops/fee values that are not actually correct.
 bool BlockAssembler::SkipMapTxEntry(
     CTxMemPool::txiter it, indexed_modified_transaction_set &mapModifiedTx,
     CTxMemPool::setEntries &failedTx) {
     assert(it != mempool.mapTx.end());
     return mapModifiedTx.count(it) || inBlock.count(it) || failedTx.count(it);
 }
 
 void BlockAssembler::SortForBlock(
     const CTxMemPool::setEntries &package, CTxMemPool::txiter entry,
     std::vector<CTxMemPool::txiter> &sortedEntries) {
     // Sort package by ancestor count. If a transaction A depends on transaction
     // B, then A's ancestor count must be greater than B's. So this is
     // sufficient to validly order the transactions for block inclusion.
     sortedEntries.clear();
     sortedEntries.insert(sortedEntries.begin(), package.begin(), package.end());
     std::sort(sortedEntries.begin(), sortedEntries.end(),
               CompareTxIterByAncestorCount());
 }
 
 /**
  * addPackageTx includes transactions paying a fee by ensuring that
  * the partial ordering of transactions is maintained.  That is to say
  * children come after parents, despite having a potentially larger fee.
  * @param[out] nPackagesSelected    How many packages were selected
  * @param[out] nDescendantsUpdated  Number of descendant transactions updated
 */
 void BlockAssembler::addPackageTxs(int &nPackagesSelected,
                                    int &nDescendantsUpdated) {
 
     // selection algorithm orders the mempool based on feerate of a
     // transaction including all unconfirmed ancestors. Since we don't remove
     // transactions from the mempool as we select them for block inclusion, we
     // need an alternate method of updating the feerate of a transaction with
     // its not-yet-selected ancestors as we go. This is accomplished by
     // walking the in-mempool descendants of selected transactions and storing
     // a temporary modified state in mapModifiedTxs. Each time through the
     // loop, we compare the best transaction in mapModifiedTxs with the next
     // transaction in the mempool to decide what transaction package to work
     // on next.
 
     // mapModifiedTx will store sorted packages after they are modified because
     // some of their txs are already in the block.
     indexed_modified_transaction_set mapModifiedTx;
     // Keep track of entries that failed inclusion, to avoid duplicate work.
     CTxMemPool::setEntries failedTx;
 
     // Start by adding all descendants of previously added txs to mapModifiedTx
     // and modifying them for their already included ancestors.
     UpdatePackagesForAdded(inBlock, mapModifiedTx);
 
     CTxMemPool::indexed_transaction_set::index<ancestor_score>::type::iterator
         mi = mempool.mapTx.get<ancestor_score>().begin();
     CTxMemPool::txiter iter;
 
     // Limit the number of attempts to add transactions to the block when it is
     // close to full; this is just a simple heuristic to finish quickly if the
     // mempool has a lot of entries.
     const int64_t MAX_CONSECUTIVE_FAILURES = 1000;
     int64_t nConsecutiveFailed = 0;
 
     while (mi != mempool.mapTx.get<ancestor_score>().end() ||
            !mapModifiedTx.empty()) {
         // First try to find a new transaction in mapTx to evaluate.
         if (mi != mempool.mapTx.get<ancestor_score>().end() &&
             SkipMapTxEntry(mempool.mapTx.project<0>(mi), mapModifiedTx,
                            failedTx)) {
             ++mi;
             continue;
         }
 
         // Now that mi is not stale, determine which transaction to evaluate:
         // the next entry from mapTx, or the best from mapModifiedTx?
         bool fUsingModified = false;
 
         modtxscoreiter modit = mapModifiedTx.get<ancestor_score>().begin();
         if (mi == mempool.mapTx.get<ancestor_score>().end()) {
             // We're out of entries in mapTx; use the entry from mapModifiedTx
             iter = modit->iter;
             fUsingModified = true;
         } else {
             // Try to compare the mapTx entry to the mapModifiedTx entry.
             iter = mempool.mapTx.project<0>(mi);
             if (modit != mapModifiedTx.get<ancestor_score>().end() &&
                 CompareModifiedEntry()(*modit, CTxMemPoolModifiedEntry(iter))) {
                 // The best entry in mapModifiedTx has higher score than the one
                 // from mapTx. Switch which transaction (package) to consider
                 iter = modit->iter;
                 fUsingModified = true;
             } else {
                 // Either no entry in mapModifiedTx, or it's worse than mapTx.
                 // Increment mi for the next loop iteration.
                 ++mi;
             }
         }
 
         // We skip mapTx entries that are inBlock, and mapModifiedTx shouldn't
         // contain anything that is inBlock.
         assert(!inBlock.count(iter));
 
         uint64_t packageSize = iter->GetSizeWithAncestors();
         Amount packageFees = iter->GetModFeesWithAncestors();
         int64_t packageSigOps = iter->GetSigOpCountWithAncestors();
         if (fUsingModified) {
             packageSize = modit->nSizeWithAncestors;
             packageFees = modit->nModFeesWithAncestors;
             packageSigOps = modit->nSigOpCountWithAncestors;
         }
 
         if (packageFees < blockMinFeeRate.GetFee(packageSize)) {
             // Everything else we might consider has a lower fee rate
             return;
         }
 
         if (!TestPackage(packageSize, packageSigOps)) {
             if (fUsingModified) {
                 // Since we always look at the best entry in mapModifiedTx, we
                 // must erase failed entries so that we can consider the next
                 // best entry on the next loop iteration
                 mapModifiedTx.get<ancestor_score>().erase(modit);
                 failedTx.insert(iter);
             }
 
             ++nConsecutiveFailed;
 
             if (nConsecutiveFailed > MAX_CONSECUTIVE_FAILURES &&
                 nBlockSize > nMaxGeneratedBlockSize - 1000) {
                 // Give up if we're close to full and haven't succeeded in a
                 // while.
                 break;
             }
 
             continue;
         }
 
         CTxMemPool::setEntries ancestors;
         uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
         std::string dummy;
         mempool.CalculateMemPoolAncestors(*iter, ancestors, nNoLimit, nNoLimit,
                                           nNoLimit, nNoLimit, dummy, false);
 
         onlyUnconfirmed(ancestors);
         ancestors.insert(iter);
 
         // Test if all tx's are Final.
         if (!TestPackageTransactions(ancestors)) {
             if (fUsingModified) {
                 mapModifiedTx.get<ancestor_score>().erase(modit);
                 failedTx.insert(iter);
             }
             continue;
         }
 
         // This transaction will make it in; reset the failed counter.
         nConsecutiveFailed = 0;
 
         // Package can be added. Sort the entries in a valid order.
         std::vector<CTxMemPool::txiter> sortedEntries;
         SortForBlock(ancestors, iter, sortedEntries);
 
         for (auto &entry : sortedEntries) {
             AddToBlock(entry);
             // Erase from the modified set, if present
             mapModifiedTx.erase(entry);
         }
 
         ++nPackagesSelected;
 
         // Update transactions that depend on each of these
         nDescendantsUpdated += UpdatePackagesForAdded(ancestors, mapModifiedTx);
     }
 }
 
 void BlockAssembler::addPriorityTxs() {
     // How much of the block should be dedicated to high-priority transactions,
     // included regardless of the fees they pay.
     if (config->GetBlockPriorityPercentage() == 0) {
         return;
     }
 
     uint64_t nBlockPrioritySize =
         nMaxGeneratedBlockSize * config->GetBlockPriorityPercentage() / 100;
 
     // This vector will be sorted into a priority queue:
     std::vector<TxCoinAgePriority> vecPriority;
     TxCoinAgePriorityCompare pricomparer;
     std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash>
         waitPriMap;
     typedef std::map<CTxMemPool::txiter, double,
                      CTxMemPool::CompareIteratorByHash>::iterator waitPriIter;
     double actualPriority = -1;
 
     vecPriority.reserve(mempool.mapTx.size());
     for (CTxMemPool::indexed_transaction_set::iterator mi =
              mempool.mapTx.begin();
          mi != mempool.mapTx.end(); ++mi) {
         double dPriority = mi->GetPriority(nHeight);
         Amount dummy;
         mempool.ApplyDeltas(mi->GetTx().GetId(), dPriority, dummy);
         vecPriority.push_back(TxCoinAgePriority(dPriority, mi));
     }
     std::make_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
 
     CTxMemPool::txiter iter;
 
     // Add a tx from priority queue to fill the part of block reserved to
     // priority transactions.
-    while (!vecPriority.empty() && !blockFinished) {
+    while (!vecPriority.empty()) {
         iter = vecPriority.front().second;
         actualPriority = vecPriority.front().first;
         std::pop_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
         vecPriority.pop_back();
 
         // If tx already in block, skip.
         if (inBlock.count(iter)) {
             // Shouldn't happen for priority txs.
             assert(false);
             continue;
         }
 
         // If tx is dependent on other mempool txs which haven't yet been
         // included then put it in the waitSet.
         if (isStillDependent(iter)) {
             waitPriMap.insert(std::make_pair(iter, actualPriority));
             continue;
         }
 
-        // If this tx fits in the block add it, otherwise keep looping.
-        if (!TestForBlock(iter)) {
+        TestForBlockResult testResult = TestForBlock(iter);
+        // Break if the block is completed
+        if (testResult == TestForBlockResult::BlockFinished) {
+            break;
+        }
+
+        // If this tx does not fit in the block, skip to next transaction.
+        if (testResult != TestForBlockResult::TXFits) {
             continue;
         }
 
         AddToBlock(iter);
 
         // If now that this txs is added we've surpassed our desired priority
         // size, then we're done adding priority transactions.
         if (nBlockSize >= nBlockPrioritySize) {
             break;
         }
 
         // if we have dropped below the AllowFreeThreshold, then we're done
         // adding priority transactions.
         if (!AllowFree(actualPriority)) {
             break;
         }
 
         // This tx was successfully added, so add transactions that depend
         // on this one to the priority queue to try again.
         for (CTxMemPool::txiter child : mempool.GetMemPoolChildren(iter)) {
             waitPriIter wpiter = waitPriMap.find(child);
             if (wpiter == waitPriMap.end()) {
                 continue;
             }
 
             vecPriority.push_back(TxCoinAgePriority(wpiter->second, child));
             std::push_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
             waitPriMap.erase(wpiter);
         }
     }
 }
 
 void IncrementExtraNonce(const Config &config, CBlock *pblock,
                          const CBlockIndex *pindexPrev,
                          unsigned int &nExtraNonce) {
     // Update nExtraNonce
     static uint256 hashPrevBlock;
     if (hashPrevBlock != pblock->hashPrevBlock) {
         nExtraNonce = 0;
         hashPrevBlock = pblock->hashPrevBlock;
     }
 
     ++nExtraNonce;
     // Height first in coinbase required for block.version=2
     unsigned int nHeight = pindexPrev->nHeight + 1;
     CMutableTransaction txCoinbase(*pblock->vtx[0]);
     txCoinbase.vin[0].scriptSig =
         (CScript() << nHeight << CScriptNum(nExtraNonce)
                    << getExcessiveBlockSizeSig(config)) +
         COINBASE_FLAGS;
     assert(txCoinbase.vin[0].scriptSig.size() <= MAX_COINBASE_SCRIPTSIG_SIZE);
 
     pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
     pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
 }
diff --git a/src/miner.h b/src/miner.h
index aeba467cda..5f600bb14e 100644
--- a/src/miner.h
+++ b/src/miner.h
@@ -1,217 +1,223 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_MINER_H
 #define BITCOIN_MINER_H
 
 #include "primitives/block.h"
 #include "txmempool.h"
 
 #include "boost/multi_index/ordered_index.hpp"
 #include "boost/multi_index_container.hpp"
 
 #include <cstdint>
 #include <memory>
 
 class CBlockIndex;
 class CChainParams;
 class Config;
 class CReserveKey;
 class CScript;
 class CWallet;
 
 static const bool DEFAULT_PRINTPRIORITY = false;
 
 struct CBlockTemplate {
     CBlock block;
     std::vector<Amount> vTxFees;
     std::vector<int64_t> vTxSigOpsCount;
 };
 
 // Container for tracking updates to ancestor feerate as we include (parent)
 // transactions in a block
 struct CTxMemPoolModifiedEntry {
     CTxMemPoolModifiedEntry(CTxMemPool::txiter entry) {
         iter = entry;
         nSizeWithAncestors = entry->GetSizeWithAncestors();
         nModFeesWithAncestors = entry->GetModFeesWithAncestors();
         nSigOpCountWithAncestors = entry->GetSigOpCountWithAncestors();
     }
 
     CTxMemPool::txiter iter;
     uint64_t nSizeWithAncestors;
     Amount nModFeesWithAncestors;
     int64_t nSigOpCountWithAncestors;
 };
 
 /**
  * Comparator for CTxMemPool::txiter objects.
  * It simply compares the internal memory address of the CTxMemPoolEntry object
  * pointed to. This means it has no meaning, and is only useful for using them
  * as key in other indexes.
  */
 struct CompareCTxMemPoolIter {
     bool operator()(const CTxMemPool::txiter &a,
                     const CTxMemPool::txiter &b) const {
         return &(*a) < &(*b);
     }
 };
 
 struct modifiedentry_iter {
     typedef CTxMemPool::txiter result_type;
     result_type operator()(const CTxMemPoolModifiedEntry &entry) const {
         return entry.iter;
     }
 };
 
 // This matches the calculation in CompareTxMemPoolEntryByAncestorFee,
 // except operating on CTxMemPoolModifiedEntry.
 // TODO: refactor to avoid duplication of this logic.
 struct CompareModifiedEntry {
     bool operator()(const CTxMemPoolModifiedEntry &a,
                     const CTxMemPoolModifiedEntry &b) const {
         double f1 = b.nSizeWithAncestors * (a.nModFeesWithAncestors / SATOSHI);
         double f2 = a.nSizeWithAncestors * (b.nModFeesWithAncestors / SATOSHI);
         if (f1 == f2) {
             return CTxMemPool::CompareIteratorByHash()(a.iter, b.iter);
         }
         return f1 > f2;
     }
 };
 
 // A comparator that sorts transactions based on number of ancestors.
 // This is sufficient to sort an ancestor package in an order that is valid
 // to appear in a block.
 struct CompareTxIterByAncestorCount {
     bool operator()(const CTxMemPool::txiter &a,
                     const CTxMemPool::txiter &b) const {
         if (a->GetCountWithAncestors() != b->GetCountWithAncestors()) {
             return a->GetCountWithAncestors() < b->GetCountWithAncestors();
         }
         return CTxMemPool::CompareIteratorByHash()(a, b);
     }
 };
 
 typedef boost::multi_index_container<
     CTxMemPoolModifiedEntry,
     boost::multi_index::indexed_by<
         boost::multi_index::ordered_unique<modifiedentry_iter,
                                            CompareCTxMemPoolIter>,
         // sorted by modified ancestor fee rate
         boost::multi_index::ordered_non_unique<
             // Reuse same tag from CTxMemPool's similar index
             boost::multi_index::tag<ancestor_score>,
             boost::multi_index::identity<CTxMemPoolModifiedEntry>,
             CompareModifiedEntry>>>
     indexed_modified_transaction_set;
 
 typedef indexed_modified_transaction_set::nth_index<0>::type::iterator
     modtxiter;
 typedef indexed_modified_transaction_set::index<ancestor_score>::type::iterator
     modtxscoreiter;
 
 struct update_for_parent_inclusion {
     update_for_parent_inclusion(CTxMemPool::txiter it) : iter(it) {}
 
     void operator()(CTxMemPoolModifiedEntry &e) {
         e.nModFeesWithAncestors -= iter->GetFee();
         e.nSizeWithAncestors -= iter->GetTxSize();
         e.nSigOpCountWithAncestors -= iter->GetSigOpCount();
     }
 
     CTxMemPool::txiter iter;
 };
 
 /** Generate a new block, without valid proof-of-work */
 class BlockAssembler {
 private:
     // The constructed block template
     std::unique_ptr<CBlockTemplate> pblocktemplate;
     // A convenience pointer that always refers to the CBlock in pblocktemplate
     CBlock *pblock;
 
     // Configuration parameters for the block size
     uint64_t nMaxGeneratedBlockSize;
     CFeeRate blockMinFeeRate;
 
     // Information on the current status of the block
     uint64_t nBlockSize;
     uint64_t nBlockTx;
     uint64_t nBlockSigOps;
     Amount nFees;
     CTxMemPool::setEntries inBlock;
 
     // Chain context for the block
     int nHeight;
     int64_t nLockTimeCutoff;
 
     const Config *config;
 
     // Variables used for addPriorityTxs
     int lastFewTxs;
-    bool blockFinished;
 
 public:
     BlockAssembler(const Config &_config);
     /** Construct a new block template with coinbase to scriptPubKeyIn */
     std::unique_ptr<CBlockTemplate>
     CreateNewBlock(const CScript &scriptPubKeyIn);
 
     uint64_t GetMaxGeneratedBlockSize() const { return nMaxGeneratedBlockSize; }
 
 private:
     // utility functions
     /** Clear the block's state and prepare for assembling a new block */
     void resetBlock();
     /** Add a tx to the block */
     void AddToBlock(CTxMemPool::txiter iter);
 
     // Methods for how to add transactions to a block.
     /** Add transactions based on tx "priority" */
     void addPriorityTxs();
     /** Add transactions based on feerate including unconfirmed ancestors
      * Increments nPackagesSelected / nDescendantsUpdated with corresponding
      * statistics from the package selection (for logging statistics). */
     void addPackageTxs(int &nPackagesSelected, int &nDescendantsUpdated);
 
+    /** Enum for the results from TestForBlock */
+    enum class TestForBlockResult : uint8_t {
+        TXFits = 0,
+        TXCantFit = 1,
+        BlockFinished = 3,
+    };
+
     // helper function for addPriorityTxs
     /** Test if tx will still "fit" in the block */
-    bool TestForBlock(CTxMemPool::txiter iter);
+    TestForBlockResult TestForBlock(CTxMemPool::txiter iter);
     /** Test if tx still has unconfirmed parents not yet in block */
     bool isStillDependent(CTxMemPool::txiter iter);
 
     // helper functions for addPackageTxs()
     /** Remove confirmed (inBlock) entries from given set */
     void onlyUnconfirmed(CTxMemPool::setEntries &testSet);
     /** Test if a new package would "fit" in the block */
     bool TestPackage(uint64_t packageSize, int64_t packageSigOpsCost);
     /** Perform checks on each transaction in a package:
      * locktime, serialized size (if necessary)
      * These checks should always succeed, and they're here
      * only as an extra check in case of suboptimal node configuration */
     bool TestPackageTransactions(const CTxMemPool::setEntries &package);
     /** Return true if given transaction from mapTx has already been evaluated,
      * or if the transaction's cached data in mapTx is incorrect. */
     bool SkipMapTxEntry(CTxMemPool::txiter it,
                         indexed_modified_transaction_set &mapModifiedTx,
                         CTxMemPool::setEntries &failedTx);
     /** Sort the package in an order that is valid to appear in a block */
     void SortForBlock(const CTxMemPool::setEntries &package,
                       CTxMemPool::txiter entry,
                       std::vector<CTxMemPool::txiter> &sortedEntries);
     /** Add descendants of given transactions to mapModifiedTx with ancestor
      * state updated assuming given transactions are inBlock. Returns number
      * of updated descendants. */
     int UpdatePackagesForAdded(const CTxMemPool::setEntries &alreadyAdded,
                                indexed_modified_transaction_set &mapModifiedTx);
 };
 
 /** Modify the extranonce in a block */
 void IncrementExtraNonce(const Config &config, CBlock *pblock,
                          const CBlockIndex *pindexPrev,
                          unsigned int &nExtraNonce);
 int64_t UpdateTime(CBlockHeader *pblock, const Config &config,
                    const CBlockIndex *pindexPrev);
 #endif // BITCOIN_MINER_H