accounts, consensus, core, eth: make chain maker consensus agnostic (#15497)

* accounts, consensus, core, eth: make chain maker consensus agnostic

* consensus, core: move CalcDifficulty to Engine interface

* consensus: add docs for calcDifficulty function

* consensus, core: minor comment fixups

23 files changed, 145 insertions, 99 deletions

diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 09288d401..2cf6b9f78 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -89,7 +89,7 @@ func (b *SimulatedBackend) Rollback() {
 }
 
 func (b *SimulatedBackend) rollback() {
-	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), b.database, 1, func(int, *core.BlockGen) {})
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
 	b.pendingBlock = blocks[0]
 	b.pendingState, _ = state.New(b.pendingBlock.Root(), state.NewDatabase(b.database))
 }
@@ -291,7 +291,7 @@ func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transa
 		panic(fmt.Errorf("invalid transaction nonce: got %d, want %d", tx.Nonce(), nonce))
 	}
 
-	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), b.database, 1, func(number int, block *core.BlockGen) {
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
 		for _, tx := range b.pendingBlock.Transactions() {
 			block.AddTx(tx)
 		}
@@ -306,7 +306,7 @@ func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transa
 func (b *SimulatedBackend) AdjustTime(adjustment time.Duration) error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
-	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), b.database, 1, func(number int, block *core.BlockGen) {
+	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
 		for _, tx := range b.pendingBlock.Transactions() {
 			block.AddTx(tx)
 		}
diff --git a/consensus/clique/clique.go b/consensus/clique/clique.go
index a98058141..2bdad9092 100644
--- a/consensus/clique/clique.go
+++ b/consensus/clique/clique.go
@@ -510,7 +510,6 @@ func (c *Clique) Prepare(chain consensus.ChainReader, header *types.Header) erro
 	header.Nonce = types.BlockNonce{}
 
 	number := header.Number.Uint64()
-
 	// Assemble the voting snapshot to check which votes make sense
 	snap, err := c.snapshot(chain, number-1, header.ParentHash, nil)
 	if err != nil {
@@ -538,10 +537,8 @@ func (c *Clique) Prepare(chain consensus.ChainReader, header *types.Header) erro
 		c.lock.RUnlock()
 	}
 	// Set the correct difficulty
-	header.Difficulty = diffNoTurn
-	if snap.inturn(header.Number.Uint64(), c.signer) {
-		header.Difficulty = diffInTurn
-	}
+	header.Difficulty = CalcDifficulty(snap, c.signer)
+
 	// Ensure the extra data has all it's components
 	if len(header.Extra) < extraVanity {
 		header.Extra = append(header.Extra, bytes.Repeat([]byte{0x00}, extraVanity-len(header.Extra))...)
@@ -655,6 +652,27 @@ func (c *Clique) Seal(chain consensus.ChainReader, block *types.Block, stop <-ch
 	return block.WithSeal(header), nil
 }
 
+// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
+// that a new block should have based on the previous blocks in the chain and the
+// current signer.
+func (c *Clique) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
+	snap, err := c.snapshot(chain, parent.Number.Uint64(), parent.Hash(), nil)
+	if err != nil {
+		return nil
+	}
+	return CalcDifficulty(snap, c.signer)
+}
+
+// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
+// that a new block should have based on the previous blocks in the chain and the
+// current signer.
+func CalcDifficulty(snap *Snapshot, signer common.Address) *big.Int {
+	if snap.inturn(snap.Number+1, signer) {
+		return new(big.Int).Set(diffInTurn)
+	}
+	return new(big.Int).Set(diffNoTurn)
+}
+
 // APIs implements consensus.Engine, returning the user facing RPC API to allow
 // controlling the signer voting.
 func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
diff --git a/consensus/consensus.go b/consensus/consensus.go
index 865238cee..be5e661c1 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -23,6 +23,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
+	"math/big"
 )
 
 // ChainReader defines a small collection of methods needed to access the local
@@ -88,6 +89,10 @@ type Engine interface {
 	// seal place on top.
 	Seal(chain ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error)
 
+	// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
+	// that a new block should have.
+	CalcDifficulty(chain ChainReader, time uint64, parent *types.Header) *big.Int
+
 	// APIs returns the RPC APIs this consensus engine provides.
 	APIs(chain ChainReader) []rpc.API
 }
diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index 2bdb18677..5fe67c851 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -240,7 +240,8 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 		return errZeroBlockTime
 	}
 	// Verify the block's difficulty based in it's timestamp and parent's difficulty
-	expected := CalcDifficulty(chain.Config(), header.Time.Uint64(), parent)
+	expected := ethash.CalcDifficulty(chain, header.Time.Uint64(), parent)
+
 	if expected.Cmp(header.Difficulty) != 0 {
 		return fmt.Errorf("invalid difficulty: have %v, want %v", header.Difficulty, expected)
 	}
@@ -287,7 +288,13 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 // CalcDifficulty is the difficulty adjustment algorithm. It returns
 // the difficulty that a new block should have when created at time
 // given the parent block's time and difficulty.
-// TODO (karalabe): Move the chain maker into this package and make this private!
+func (ethash *Ethash) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
+	return CalcDifficulty(chain.Config(), time, parent)
+}
+
+// CalcDifficulty is the difficulty adjustment algorithm. It returns
+// the difficulty that a new block should have when created at time
+// given the parent block's time and difficulty.
 func CalcDifficulty(config *params.ChainConfig, time uint64, parent *types.Header) *big.Int {
 	next := new(big.Int).Add(parent.Number, big1)
 	switch {
@@ -502,8 +509,7 @@ func (ethash *Ethash) Prepare(chain consensus.ChainReader, header *types.Header)
 	if parent == nil {
 		return consensus.ErrUnknownAncestor
 	}
-	header.Difficulty = CalcDifficulty(chain.Config(), header.Time.Uint64(), parent)
-
+	header.Difficulty = ethash.CalcDifficulty(chain, header.Time.Uint64(), parent)
 	return nil
 }
 
@@ -511,7 +517,7 @@ func (ethash *Ethash) Prepare(chain consensus.ChainReader, header *types.Header)
 // setting the final state and assembling the block.
 func (ethash *Ethash) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
 	// Accumulate any block and uncle rewards and commit the final state root
-	AccumulateRewards(chain.Config(), state, header, uncles)
+	accumulateRewards(chain.Config(), state, header, uncles)
 	header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
 
 	// Header seems complete, assemble into a block and return
@@ -527,8 +533,7 @@ var (
 // AccumulateRewards credits the coinbase of the given block with the mining
 // reward. The total reward consists of the static block reward and rewards for
 // included uncles. The coinbase of each uncle block is also rewarded.
-// TODO (karalabe): Move the chain maker into this package and make this private!
-func AccumulateRewards(config *params.ChainConfig, state *state.StateDB, header *types.Header, uncles []*types.Header) {
+func accumulateRewards(config *params.ChainConfig, state *state.StateDB, header *types.Header, uncles []*types.Header) {
 	// Select the correct block reward based on chain progression
 	blockReward := FrontierBlockReward
 	if config.IsByzantium(header.Number) {
diff --git a/consensus/ethash/consensus_test.go b/consensus/ethash/consensus_test.go
index a58d220ef..438a99dd6 100644
--- a/consensus/ethash/consensus_test.go
+++ b/consensus/ethash/consensus_test.go
@@ -71,6 +71,7 @@ func TestCalcDifficulty(t *testing.T) {
 	}
 
 	config := &params.ChainConfig{HomesteadBlock: big.NewInt(1150000)}
+
 	for name, test := range tests {
 		number := new(big.Int).Sub(test.CurrentBlocknumber, big.NewInt(1))
 		diff := CalcDifficulty(config, test.CurrentTimestamp, &types.Header{
diff --git a/core/bench_test.go b/core/bench_test.go
index ab25c27d3..9c7cd81c4 100644
--- a/core/bench_test.go
+++ b/core/bench_test.go
@@ -170,7 +170,7 @@ func benchInsertChain(b *testing.B, disk bool, gen func(int, *BlockGen)) {
 		Alloc:  GenesisAlloc{benchRootAddr: {Balance: benchRootFunds}},
 	}
 	genesis := gspec.MustCommit(db)
-	chain, _ := GenerateChain(gspec.Config, genesis, db, b.N, gen)
+	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, b.N, gen)
 
 	// Time the insertion of the new chain.
 	// State and blocks are stored in the same DB.
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index 6d54c2b93..e668601f3 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -35,7 +35,7 @@ func TestHeaderVerification(t *testing.T) {
 		testdb, _ = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
-		blocks, _ = GenerateChain(params.TestChainConfig, genesis, testdb, 8, nil)
+		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 8, nil)
 	)
 	headers := make([]*types.Header, len(blocks))
 	for i, block := range blocks {
@@ -87,7 +87,7 @@ func testHeaderConcurrentVerification(t *testing.T, threads int) {
 		testdb, _ = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
-		blocks, _ = GenerateChain(params.TestChainConfig, genesis, testdb, 8, nil)
+		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 8, nil)
 	)
 	headers := make([]*types.Header, len(blocks))
 	seals := make([]bool, len(blocks))
@@ -159,7 +159,7 @@ func testHeaderConcurrentAbortion(t *testing.T, threads int) {
 		testdb, _ = ethdb.NewMemDatabase()
 		gspec     = &Genesis{Config: params.TestChainConfig}
 		genesis   = gspec.MustCommit(testdb)
-		blocks, _ = GenerateChain(params.TestChainConfig, genesis, testdb, 1024, nil)
+		blocks, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), testdb, 1024, nil)
 	)
 	headers := make([]*types.Header, len(blocks))
 	seals := make([]bool, len(blocks))
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index cb1df8d4b..cb2e47104 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -57,7 +57,7 @@ func newTestBlockChain(fake bool) *BlockChain {
 // Test fork of length N starting from block i
 func testFork(t *testing.T, blockchain *BlockChain, i, n int, full bool, comparator func(td1, td2 *big.Int)) {
 	// Copy old chain up to #i into a new db
-	db, blockchain2, err := newCanonical(i, full)
+	db, blockchain2, err := newCanonical(ethash.NewFaker(), i, full)
 	if err != nil {
 		t.Fatal("could not make new canonical in testFork", err)
 	}
@@ -81,12 +81,12 @@ func testFork(t *testing.T, blockchain *BlockChain, i, n int, full bool, compara
 		headerChainB []*types.Header
 	)
 	if full {
-		blockChainB = makeBlockChain(blockchain2.CurrentBlock(), n, db, forkSeed)
+		blockChainB = makeBlockChain(blockchain2.CurrentBlock(), n, ethash.NewFaker(), db, forkSeed)
 		if _, err := blockchain2.InsertChain(blockChainB); err != nil {
 			t.Fatalf("failed to insert forking chain: %v", err)
 		}
 	} else {
-		headerChainB = makeHeaderChain(blockchain2.CurrentHeader(), n, db, forkSeed)
+		headerChainB = makeHeaderChain(blockchain2.CurrentHeader(), n, ethash.NewFaker(), db, forkSeed)
 		if _, err := blockchain2.InsertHeaderChain(headerChainB, 1); err != nil {
 			t.Fatalf("failed to insert forking chain: %v", err)
 		}
@@ -186,7 +186,7 @@ func TestLastBlock(t *testing.T) {
 	bchain := newTestBlockChain(false)
 	defer bchain.Stop()
 
-	block := makeBlockChain(bchain.CurrentBlock(), 1, bchain.chainDb, 0)[0]
+	block := makeBlockChain(bchain.CurrentBlock(), 1, ethash.NewFaker(), bchain.chainDb, 0)[0]
 	bchain.insert(block)
 	if block.Hash() != GetHeadBlockHash(bchain.chainDb) {
 		t.Errorf("Write/Get HeadBlockHash failed")
@@ -202,7 +202,7 @@ func testExtendCanonical(t *testing.T, full bool) {
 	length := 5
 
 	// Make first chain starting from genesis
-	_, processor, err := newCanonical(length, full)
+	_, processor, err := newCanonical(ethash.NewFaker(), length, full)
 	if err != nil {
 		t.Fatalf("failed to make new canonical chain: %v", err)
 	}
@@ -230,7 +230,7 @@ func testShorterFork(t *testing.T, full bool) {
 	length := 10
 
 	// Make first chain starting from genesis
-	_, processor, err := newCanonical(length, full)
+	_, processor, err := newCanonical(ethash.NewFaker(), length, full)
 	if err != nil {
 		t.Fatalf("failed to make new canonical chain: %v", err)
 	}
@@ -260,7 +260,7 @@ func testLongerFork(t *testing.T, full bool) {
 	length := 10
 
 	// Make first chain starting from genesis
-	_, processor, err := newCanonical(length, full)
+	_, processor, err := newCanonical(ethash.NewFaker(), length, full)
 	if err != nil {
 		t.Fatalf("failed to make new canonical chain: %v", err)
 	}
@@ -290,7 +290,7 @@ func testEqualFork(t *testing.T, full bool) {
 	length := 10
 
 	// Make first chain starting from genesis
-	_, processor, err := newCanonical(length, full)
+	_, processor, err := newCanonical(ethash.NewFaker(), length, full)
 	if err != nil {
 		t.Fatalf("failed to make new canonical chain: %v", err)
 	}
@@ -317,7 +317,7 @@ func TestBrokenBlockChain(t *testing.T)  { testBrokenChain(t, true) }
 
 func testBrokenChain(t *testing.T, full bool) {
 	// Make chain starting from genesis
-	db, blockchain, err := newCanonical(10, full)
+	db, blockchain, err := newCanonical(ethash.NewFaker(), 10, full)
 	if err != nil {
 		t.Fatalf("failed to make new canonical chain: %v", err)
 	}
@@ -325,12 +325,12 @@ func testBrokenChain(t *testing.T, full bool) {
 
 	// Create a forked chain, and try to insert with a missing link
 	if full {
-		chain := makeBlockChain(blockchain.CurrentBlock(), 5, db, forkSeed)[1:]
+		chain := makeBlockChain(blockchain.CurrentBlock(), 5, ethash.NewFaker(), db, forkSeed)[1:]
 		if err := testBlockChainImport(chain, blockchain); err == nil {
 			t.Errorf("broken block chain not reported")
 		}
 	} else {
-		chain := makeHeaderChain(blockchain.CurrentHeader(), 5, db, forkSeed)[1:]
+		chain := makeHeaderChain(blockchain.CurrentHeader(), 5, ethash.NewFaker(), db, forkSeed)[1:]
 		if err := testHeaderChainImport(chain, blockchain); err == nil {
 			t.Errorf("broken header chain not reported")
 		}
@@ -523,7 +523,7 @@ func TestBlocksInsertNonceError(t *testing.T)  { testInsertNonceError(t, true) }
 func testInsertNonceError(t *testing.T, full bool) {
 	for i := 1; i < 25 && !t.Failed(); i++ {
 		// Create a pristine chain and database
-		db, blockchain, err := newCanonical(0, full)
+		db, blockchain, err := newCanonical(ethash.NewFaker(), 0, full)
 		if err != nil {
 			t.Fatalf("failed to create pristine chain: %v", err)
 		}
@@ -536,7 +536,7 @@ func testInsertNonceError(t *testing.T, full bool) {
 			failNum uint64
 		)
 		if full {
-			blocks := makeBlockChain(blockchain.CurrentBlock(), i, db, 0)
+			blocks := makeBlockChain(blockchain.CurrentBlock(), i, ethash.NewFaker(), db, 0)
 
 			failAt = rand.Int() % len(blocks)
 			failNum = blocks[failAt].NumberU64()
@@ -544,7 +544,7 @@ func testInsertNonceError(t *testing.T, full bool) {
 			blockchain.engine = ethash.NewFakeFailer(failNum)
 			failRes, err = blockchain.InsertChain(blocks)
 		} else {
-			headers := makeHeaderChain(blockchain.CurrentHeader(), i, db, 0)
+			headers := makeHeaderChain(blockchain.CurrentHeader(), i, ethash.NewFaker(), db, 0)
 
 			failAt = rand.Int() % len(headers)
 			failNum = headers[failAt].Number.Uint64()
@@ -588,7 +588,7 @@ func TestFastVsFullChains(t *testing.T) {
 		genesis = gspec.MustCommit(gendb)
 		signer  = types.NewEIP155Signer(gspec.Config.ChainId)
 	)
-	blocks, receipts := GenerateChain(gspec.Config, genesis, gendb, 1024, func(i int, block *BlockGen) {
+	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, 1024, func(i int, block *BlockGen) {
 		block.SetCoinbase(common.Address{0x00})
 
 		// If the block number is multiple of 3, send a few bonus transactions to the miner
@@ -673,7 +673,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 		genesis  = gspec.MustCommit(gendb)
 	)
 	height := uint64(1024)
-	blocks, receipts := GenerateChain(gspec.Config, genesis, gendb, int(height), nil)
+	blocks, receipts := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), gendb, int(height), nil)
 
 	// Configure a subchain to roll back
 	remove := []common.Hash{}
@@ -781,7 +781,7 @@ func TestChainTxReorgs(t *testing.T) {
 	//  - futureAdd: transaction added after the reorg has already finished
 	var pastAdd, freshAdd, futureAdd *types.Transaction
 
-	chain, _ := GenerateChain(gspec.Config, genesis, db, 3, func(i int, gen *BlockGen) {
+	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
 			pastDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), bigTxGas, nil, nil), signer, key2)
@@ -806,7 +806,7 @@ func TestChainTxReorgs(t *testing.T) {
 	defer blockchain.Stop()
 
 	// overwrite the old chain
-	chain, _ = GenerateChain(gspec.Config, genesis, db, 5, func(i int, gen *BlockGen) {
+	chain, _ = GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
 			pastAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key3)
@@ -875,7 +875,7 @@ func TestLogReorgs(t *testing.T) {
 
 	rmLogsCh := make(chan RemovedLogsEvent)
 	blockchain.SubscribeRemovedLogsEvent(rmLogsCh)
-	chain, _ := GenerateChain(params.TestChainConfig, genesis, db, 2, func(i int, gen *BlockGen) {
+	chain, _ := GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 2, func(i int, gen *BlockGen) {
 		if i == 1 {
 			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), code), signer, key1)
 			if err != nil {
@@ -888,7 +888,7 @@ func TestLogReorgs(t *testing.T) {
 		t.Fatalf("failed to insert chain: %v", err)
 	}
 
-	chain, _ = GenerateChain(params.TestChainConfig, genesis, db, 3, func(i int, gen *BlockGen) {})
+	chain, _ = GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {})
 	if _, err := blockchain.InsertChain(chain); err != nil {
 		t.Fatalf("failed to insert forked chain: %v", err)
 	}
@@ -920,12 +920,12 @@ func TestReorgSideEvent(t *testing.T) {
 	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
-	chain, _ := GenerateChain(gspec.Config, genesis, db, 3, func(i int, gen *BlockGen) {})
+	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {})
 	if _, err := blockchain.InsertChain(chain); err != nil {
 		t.Fatalf("failed to insert chain: %v", err)
 	}
 
-	replacementBlocks, _ := GenerateChain(gspec.Config, genesis, db, 4, func(i int, gen *BlockGen) {
+	replacementBlocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 4, func(i int, gen *BlockGen) {
 		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), nil), signer, key1)
 		if i == 2 {
 			gen.OffsetTime(-9)
@@ -992,7 +992,7 @@ func TestCanonicalBlockRetrieval(t *testing.T) {
 	bc := newTestBlockChain(true)
 	defer bc.Stop()
 
-	chain, _ := GenerateChain(bc.config, bc.genesisBlock, bc.chainDb, 10, func(i int, gen *BlockGen) {})
+	chain, _ := GenerateChain(bc.config, bc.genesisBlock, ethash.NewFaker(), bc.chainDb, 10, func(i int, gen *BlockGen) {})
 
 	var pend sync.WaitGroup
 	pend.Add(len(chain))
@@ -1046,7 +1046,7 @@ func TestEIP155Transition(t *testing.T) {
 	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
-	blocks, _ := GenerateChain(gspec.Config, genesis, db, 4, func(i int, block *BlockGen) {
+	blocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 4, func(i int, block *BlockGen) {
 		var (
 			tx      *types.Transaction
 			err     error
@@ -1109,7 +1109,7 @@ func TestEIP155Transition(t *testing.T) {
 
 	// generate an invalid chain id transaction
 	config := &params.ChainConfig{ChainId: big.NewInt(2), EIP155Block: big.NewInt(2), HomesteadBlock: new(big.Int)}
-	blocks, _ = GenerateChain(config, blocks[len(blocks)-1], db, 4, func(i int, block *BlockGen) {
+	blocks, _ = GenerateChain(config, blocks[len(blocks)-1], ethash.NewFaker(), db, 4, func(i int, block *BlockGen) {
 		var (
 			tx      *types.Transaction
 			err     error
@@ -1154,7 +1154,7 @@ func TestEIP161AccountRemoval(t *testing.T) {
 	blockchain, _ := NewBlockChain(db, gspec.Config, ethash.NewFaker(), vm.Config{})
 	defer blockchain.Stop()
 
-	blocks, _ := GenerateChain(gspec.Config, genesis, db, 3, func(i int, block *BlockGen) {
+	blocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, block *BlockGen) {
 		var (
 			tx     *types.Transaction
 			err    error
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 59af633df..0e5e3791e 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -21,7 +21,7 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -39,11 +39,12 @@ var (
 // BlockGen creates blocks for testing.
 // See GenerateChain for a detailed explanation.
 type BlockGen struct {
-	i       int
-	parent  *types.Block
-	chain   []*types.Block
-	header  *types.Header
-	statedb *state.StateDB
+	i           int
+	parent      *types.Block
+	chain       []*types.Block
+	chainReader consensus.ChainReader
+	header      *types.Header
+	statedb     *state.StateDB
 
 	gasPool  *GasPool
 	txs      []*types.Transaction
@@ -51,6 +52,7 @@ type BlockGen struct {
 	uncles   []*types.Header
 
 	config *params.ChainConfig
+	engine consensus.Engine
 }
 
 // SetCoinbase sets the coinbase of the generated block.
@@ -141,7 +143,7 @@ func (b *BlockGen) OffsetTime(seconds int64) {
 	if b.header.Time.Cmp(b.parent.Header().Time) <= 0 {
 		panic("block time out of range")
 	}
-	b.header.Difficulty = ethash.CalcDifficulty(b.config, b.header.Time.Uint64(), b.parent.Header())
+	b.header.Difficulty = b.engine.CalcDifficulty(b.chainReader, b.header.Time.Uint64(), b.parent.Header())
 }
 
 // GenerateChain creates a chain of n blocks. The first block's
@@ -156,44 +158,54 @@ func (b *BlockGen) OffsetTime(seconds int64) {
 // Blocks created by GenerateChain do not contain valid proof of work
 // values. Inserting them into BlockChain requires use of FakePow or
 // a similar non-validating proof of work implementation.
-func GenerateChain(config *params.ChainConfig, parent *types.Block, db ethdb.Database, n int, gen func(int, *BlockGen)) ([]*types.Block, []types.Receipts) {
+func GenerateChain(config *params.ChainConfig, parent *types.Block, engine consensus.Engine, db ethdb.Database, n int, gen func(int, *BlockGen)) ([]*types.Block, []types.Receipts) {
 	if config == nil {
 		config = params.TestChainConfig
 	}
 	blocks, receipts := make(types.Blocks, n), make([]types.Receipts, n)
-	genblock := func(i int, h *types.Header, statedb *state.StateDB) (*types.Block, types.Receipts) {
-		b := &BlockGen{parent: parent, i: i, chain: blocks, header: h, statedb: statedb, config: config}
+	genblock := func(i int, parent *types.Block, statedb *state.StateDB) (*types.Block, types.Receipts) {
+		// TODO(karalabe): This is needed for clique, which depends on multiple blocks.
+		// It's nonetheless ugly to spin up a blockchain here. Get rid of this somehow.
+		blockchain, _ := NewBlockChain(db, config, engine, vm.Config{})
+		defer blockchain.Stop()
+
+		b := &BlockGen{i: i, parent: parent, chain: blocks, chainReader: blockchain, statedb: statedb, config: config, engine: engine}
+		b.header = makeHeader(b.chainReader, parent, statedb, b.engine)
+
 		// Mutate the state and block according to any hard-fork specs
 		if daoBlock := config.DAOForkBlock; daoBlock != nil {
 			limit := new(big.Int).Add(daoBlock, params.DAOForkExtraRange)
-			if h.Number.Cmp(daoBlock) >= 0 && h.Number.Cmp(limit) < 0 {
+			if b.header.Number.Cmp(daoBlock) >= 0 && b.header.Number.Cmp(limit) < 0 {
 				if config.DAOForkSupport {
-					h.Extra = common.CopyBytes(params.DAOForkBlockExtra)
+					b.header.Extra = common.CopyBytes(params.DAOForkBlockExtra)
 				}
 			}
 		}
-		if config.DAOForkSupport && config.DAOForkBlock != nil && config.DAOForkBlock.Cmp(h.Number) == 0 {
+		if config.DAOForkSupport && config.DAOForkBlock != nil && config.DAOForkBlock.Cmp(b.header.Number) == 0 {
 			misc.ApplyDAOHardFork(statedb)
 		}
 		// Execute any user modifications to the block and finalize it
 		if gen != nil {
 			gen(i, b)
 		}
-		ethash.AccumulateRewards(config, statedb, h, b.uncles)
-		root, err := statedb.CommitTo(db, config.IsEIP158(h.Number))
-		if err != nil {
-			panic(fmt.Sprintf("state write error: %v", err))
+
+		if b.engine != nil {
+			block, _ := b.engine.Finalize(b.chainReader, b.header, statedb, b.txs, b.uncles, b.receipts)
+			// Write state changes to db
+			_, err := statedb.CommitTo(db, config.IsEIP158(b.header.Number))
+			if err != nil {
+				panic(fmt.Sprintf("state write error: %v", err))
+			}
+			return block, b.receipts
 		}
-		h.Root = root
-		return types.NewBlock(h, b.txs, b.uncles, b.receipts), b.receipts
+		return nil, nil
 	}
 	for i := 0; i < n; i++ {
 		statedb, err := state.New(parent.Root(), state.NewDatabase(db))
 		if err != nil {
 			panic(err)
 		}
-		header := makeHeader(config, parent, statedb)
-		block, receipt := genblock(i, header, statedb)
+		block, receipt := genblock(i, parent, statedb)
 		blocks[i] = block
 		receipts[i] = receipt
 		parent = block
@@ -201,7 +213,7 @@ func GenerateChain(config *params.ChainConfig, parent *types.Block, db ethdb.Dat
 	return blocks, receipts
 }
 
-func makeHeader(config *params.ChainConfig, parent *types.Block, state *state.StateDB) *types.Header {
+func makeHeader(chain consensus.ChainReader, parent *types.Block, state *state.StateDB, engine consensus.Engine) *types.Header {
 	var time *big.Int
 	if parent.Time() == nil {
 		time = big.NewInt(10)
@@ -210,10 +222,10 @@ func makeHeader(config *params.ChainConfig, parent *types.Block, state *state.St
 	}
 
 	return &types.Header{
-		Root:       state.IntermediateRoot(config.IsEIP158(parent.Number())),
+		Root:       state.IntermediateRoot(chain.Config().IsEIP158(parent.Number())),
 		ParentHash: parent.Hash(),
 		Coinbase:   parent.Coinbase(),
-		Difficulty: ethash.CalcDifficulty(config, time.Uint64(), &types.Header{
+		Difficulty: engine.CalcDifficulty(chain, time.Uint64(), &types.Header{
 			Number:     parent.Number(),
 			Time:       new(big.Int).Sub(time, big.NewInt(10)),
 			Difficulty: parent.Difficulty(),
@@ -229,32 +241,32 @@ func makeHeader(config *params.ChainConfig, parent *types.Block, state *state.St
 // newCanonical creates a chain database, and injects a deterministic canonical
 // chain. Depending on the full flag, if creates either a full block chain or a
 // header only chain.
-func newCanonical(n int, full bool) (ethdb.Database, *BlockChain, error) {
+func newCanonical(engine consensus.Engine, n int, full bool) (ethdb.Database, *BlockChain, error) {
 	// Initialize a fresh chain with only a genesis block
 	gspec := new(Genesis)
 	db, _ := ethdb.NewMemDatabase()
 	genesis := gspec.MustCommit(db)
 
-	blockchain, _ := NewBlockChain(db, params.AllEthashProtocolChanges, ethash.NewFaker(), vm.Config{})
+	blockchain, _ := NewBlockChain(db, params.AllEthashProtocolChanges, engine, vm.Config{})
 	// Create and inject the requested chain
 	if n == 0 {
 		return db, blockchain, nil
 	}
 	if full {
 		// Full block-chain requested
-		blocks := makeBlockChain(genesis, n, db, canonicalSeed)
+		blocks := makeBlockChain(genesis, n, engine, db, canonicalSeed)
 		_, err := blockchain.InsertChain(blocks)
 		return db, blockchain, err
 	}
 	// Header-only chain requested
-	headers := makeHeaderChain(genesis.Header(), n, db, canonicalSeed)
+	headers := makeHeaderChain(genesis.Header(), n, engine, db, canonicalSeed)
 	_, err := blockchain.InsertHeaderChain(headers, 1)
 	return db, blockchain, err
 }
 
 // makeHeaderChain creates a deterministic chain of headers rooted at parent.
-func makeHeaderChain(parent *types.Header, n int, db ethdb.Database, seed int) []*types.Header {
-	blocks := makeBlockChain(types.NewBlockWithHeader(parent), n, db, seed)
+func makeHeaderChain(parent *types.Header, n int, engine consensus.Engine, db ethdb.Database, seed int) []*types.Header {
+	blocks := makeBlockChain(types.NewBlockWithHeader(parent), n, engine, db, seed)
 	headers := make([]*types.Header, len(blocks))
 	for i, block := range blocks {
 		headers[i] = block.Header()
@@ -263,8 +275,8 @@ func makeHeaderChain(parent *types.Header, n int, db ethdb.Database, seed int) [
 }
 
 // makeBlockChain creates a deterministic chain of blocks rooted at parent.
-func makeBlockChain(parent *types.Block, n int, db ethdb.Database, seed int) []*types.Block {
-	blocks, _ := GenerateChain(params.TestChainConfig, parent, db, n, func(i int, b *BlockGen) {
+func makeBlockChain(parent *types.Block, n int, engine consensus.Engine, db ethdb.Database, seed int) []*types.Block {
+	blocks, _ := GenerateChain(params.TestChainConfig, parent, engine, db, n, func(i int, b *BlockGen) {
 		b.SetCoinbase(common.Address{0: byte(seed), 19: byte(i)})
 	})
 	return blocks
diff --git a/core/chain_makers_test.go b/core/chain_makers_test.go
index 2260c62fb..011efe342 100644
--- a/core/chain_makers_test.go
+++ b/core/chain_makers_test.go
@@ -50,7 +50,7 @@ func ExampleGenerateChain() {
 	// each block and adds different features to gen based on the
 	// block index.
 	signer := types.HomesteadSigner{}
-	chain, _ := GenerateChain(gspec.Config, genesis, db, 5, func(i int, gen *BlockGen) {
+	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
 			// In block 1, addr1 sends addr2 some ether.
diff --git a/core/dao_test.go b/core/dao_test.go
index b9898ff7c..43e2982a5 100644
--- a/core/dao_test.go
+++ b/core/dao_test.go
@@ -35,7 +35,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	db, _ := ethdb.NewMemDatabase()
 	gspec := new(Genesis)
 	genesis := gspec.MustCommit(db)
-	prefix, _ := GenerateChain(params.TestChainConfig, genesis, db, int(forkBlock.Int64()-1), func(i int, gen *BlockGen) {})
+	prefix, _ := GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, int(forkBlock.Int64()-1), func(i int, gen *BlockGen) {})
 
 	// Create the concurrent, conflicting two nodes
 	proDb, _ := ethdb.NewMemDatabase()
@@ -79,12 +79,12 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		if _, err := bc.InsertChain(blocks); err != nil {
 			t.Fatalf("failed to import contra-fork chain for expansion: %v", err)
 		}
-		blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := conBc.InsertChain(blocks); err == nil {
 			t.Fatalf("contra-fork chain accepted pro-fork block: %v", blocks[0])
 		}
 		// Create a proper no-fork block for the contra-forker
-		blocks, _ = GenerateChain(&conConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&conConf, conBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := conBc.InsertChain(blocks); err != nil {
 			t.Fatalf("contra-fork chain didn't accepted no-fork block: %v", err)
 		}
@@ -101,12 +101,12 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		if _, err := bc.InsertChain(blocks); err != nil {
 			t.Fatalf("failed to import pro-fork chain for expansion: %v", err)
 		}
-		blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := proBc.InsertChain(blocks); err == nil {
 			t.Fatalf("pro-fork chain accepted contra-fork block: %v", blocks[0])
 		}
 		// Create a proper pro-fork block for the pro-forker
-		blocks, _ = GenerateChain(&proConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+		blocks, _ = GenerateChain(&proConf, proBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 		if _, err := proBc.InsertChain(blocks); err != nil {
 			t.Fatalf("pro-fork chain didn't accepted pro-fork block: %v", err)
 		}
@@ -124,7 +124,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	if _, err := bc.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to import contra-fork chain for expansion: %v", err)
 	}
-	blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+	blocks, _ = GenerateChain(&proConf, conBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 	if _, err := conBc.InsertChain(blocks); err != nil {
 		t.Fatalf("contra-fork chain didn't accept pro-fork block post-fork: %v", err)
 	}
@@ -141,7 +141,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	if _, err := bc.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to import pro-fork chain for expansion: %v", err)
 	}
-	blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), db, 1, func(i int, gen *BlockGen) {})
+	blocks, _ = GenerateChain(&conConf, proBc.CurrentBlock(), ethash.NewFaker(), db, 1, func(i int, gen *BlockGen) {})
 	if _, err := proBc.InsertChain(blocks); err != nil {
 		t.Fatalf("pro-fork chain didn't accept contra-fork block post-fork: %v", err)
 	}
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 7d1cc8c34..e14264944 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -26,6 +26,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -107,7 +108,7 @@ func newTester() *downloadTester {
 // reassembly.
 func (dl *downloadTester) makeChain(n int, seed byte, parent *types.Block, parentReceipts types.Receipts, heavy bool) ([]common.Hash, map[common.Hash]*types.Header, map[common.Hash]*types.Block, map[common.Hash]types.Receipts) {
 	// Generate the block chain
-	blocks, receipts := core.GenerateChain(params.TestChainConfig, parent, dl.peerDb, n, func(i int, block *core.BlockGen) {
+	blocks, receipts := core.GenerateChain(params.TestChainConfig, parent, ethash.NewFaker(), dl.peerDb, n, func(i int, block *core.BlockGen) {
 		block.SetCoinbase(common.Address{seed})
 
 		// If a heavy chain is requested, delay blocks to raise difficulty
diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go
index 9889e6cc5..e6a639417 100644
--- a/eth/fetcher/fetcher_test.go
+++ b/eth/fetcher/fetcher_test.go
@@ -25,6 +25,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -45,7 +46,7 @@ var (
 // contains a transaction and every 5th an uncle to allow testing correct block
 // reassembly.
 func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
-	blocks, _ := core.GenerateChain(params.TestChainConfig, parent, testdb, n, func(i int, block *core.BlockGen) {
+	blocks, _ := core.GenerateChain(params.TestChainConfig, parent, ethash.NewFaker(), testdb, n, func(i int, block *core.BlockGen) {
 		block.SetCoinbase(common.Address{seed})
 
 		// If the block number is multiple of 3, send a bonus transaction to the miner
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index 7da114fda..a5025db3d 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -26,6 +26,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/bloombits"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -136,7 +137,7 @@ func TestBlockSubscription(t *testing.T) {
 		backend     = &testBackend{mux, db, 0, txFeed, rmLogsFeed, logsFeed, chainFeed}
 		api         = NewPublicFilterAPI(backend, false)
 		genesis     = new(core.Genesis).MustCommit(db)
-		chain, _    = core.GenerateChain(params.TestChainConfig, genesis, db, 10, func(i int, gen *core.BlockGen) {})
+		chain, _    = core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 10, func(i int, gen *core.BlockGen) {})
 		chainEvents = []core.ChainEvent{}
 	)
 
diff --git a/eth/filters/filter_test.go b/eth/filters/filter_test.go
index 11235e95a..729d0afc8 100644
--- a/eth/filters/filter_test.go
+++ b/eth/filters/filter_test.go
@@ -24,6 +24,7 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -65,7 +66,7 @@ func BenchmarkFilters(b *testing.B) {
 	defer db.Close()
 
 	genesis := core.GenesisBlockForTesting(db, addr1, big.NewInt(1000000))
-	chain, receipts := core.GenerateChain(params.TestChainConfig, genesis, db, 100010, func(i int, gen *core.BlockGen) {
+	chain, receipts := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 100010, func(i int, gen *core.BlockGen) {
 		switch i {
 		case 2403:
 			receipt := makeReceipt(addr1)
@@ -132,7 +133,7 @@ func TestFilters(t *testing.T) {
 	defer db.Close()
 
 	genesis := core.GenesisBlockForTesting(db, addr, big.NewInt(1000000))
-	chain, receipts := core.GenerateChain(params.TestChainConfig, genesis, db, 1000, func(i int, gen *core.BlockGen) {
+	chain, receipts := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 1000, func(i int, gen *core.BlockGen) {
 		switch i {
 		case 1:
 			receipt := types.NewReceipt(nil, false, new(big.Int))
diff --git a/eth/handler_test.go b/eth/handler_test.go
index 6752cd2a8..ebbd83c3a 100644
--- a/eth/handler_test.go
+++ b/eth/handler_test.go
@@ -498,7 +498,7 @@ func testDAOChallenge(t *testing.T, localForked, remoteForked bool, timeout bool
 	}
 	// Create a block to reply to the challenge if no timeout is simulated
 	if !timeout {
-		blocks, _ := core.GenerateChain(&params.ChainConfig{}, genesis, db, 1, func(i int, block *core.BlockGen) {
+		blocks, _ := core.GenerateChain(&params.ChainConfig{}, genesis, ethash.NewFaker(), db, 1, func(i int, block *core.BlockGen) {
 			if remoteForked {
 				block.SetExtra(params.DAOForkBlockExtra)
 			}
diff --git a/eth/helper_test.go b/eth/helper_test.go
index f02242b15..bfb003c8b 100644
--- a/eth/helper_test.go
+++ b/eth/helper_test.go
@@ -61,7 +61,7 @@ func newTestProtocolManager(mode downloader.SyncMode, blocks int, generator func
 		genesis       = gspec.MustCommit(db)
 		blockchain, _ = core.NewBlockChain(db, gspec.Config, engine, vm.Config{})
 	)
-	chain, _ := core.GenerateChain(gspec.Config, genesis, db, blocks, generator)
+	chain, _ := core.GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, blocks, generator)
 	if _, err := blockchain.InsertChain(chain); err != nil {
 		panic(err)
 	}
diff --git a/les/handler_test.go b/les/handler_test.go
index a9dac89b4..6207061cc 100644
--- a/les/handler_test.go
+++ b/les/handler_test.go
@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -459,7 +460,7 @@ func TestTransactionStatusLes2(t *testing.T) {
 	test(tx3, false, txStatus{Status: core.TxStatusPending})
 
 	// generate and add a block with tx1 and tx2 included
-	gchain, _ := core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), db, 1, func(i int, block *core.BlockGen) {
+	gchain, _ := core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), ethash.NewFaker(), db, 1, func(i int, block *core.BlockGen) {
 		block.AddTx(tx1)
 		block.AddTx(tx2)
 	})
@@ -483,7 +484,7 @@ func TestTransactionStatusLes2(t *testing.T) {
 	test(tx2, false, txStatus{Status: core.TxStatusIncluded, Lookup: &core.TxLookupEntry{BlockHash: block1hash, BlockIndex: 1, Index: 1}})
 
 	// create a reorg that rolls them back
-	gchain, _ = core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), db, 2, func(i int, block *core.BlockGen) {})
+	gchain, _ = core.GenerateChain(params.TestChainConfig, chain.GetBlockByNumber(0), ethash.NewFaker(), db, 2, func(i int, block *core.BlockGen) {})
 	if _, err := chain.InsertChain(gchain); err != nil {
 		panic(err)
 	}
diff --git a/les/helper_test.go b/les/helper_test.go
index a06f84cca..92a98e27e 100644
--- a/les/helper_test.go
+++ b/les/helper_test.go
@@ -149,7 +149,7 @@ func newTestProtocolManager(lightSync bool, blocks int, generator func(int, *cor
 		chain, _ = light.NewLightChain(odr, gspec.Config, engine)
 	} else {
 		blockchain, _ := core.NewBlockChain(db, gspec.Config, engine, vm.Config{})
-		gchain, _ := core.GenerateChain(gspec.Config, genesis, db, blocks, generator)
+		gchain, _ := core.GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, blocks, generator)
 		if _, err := blockchain.InsertChain(gchain); err != nil {
 			panic(err)
 		}
diff --git a/light/lightchain_test.go b/light/lightchain_test.go
index 40a4d396a..0af7551d4 100644
--- a/light/lightchain_test.go
+++ b/light/lightchain_test.go
@@ -37,7 +37,7 @@ var (
 
 // makeHeaderChain creates a deterministic chain of headers rooted at parent.
 func makeHeaderChain(parent *types.Header, n int, db ethdb.Database, seed int) []*types.Header {
-	blocks, _ := core.GenerateChain(params.TestChainConfig, types.NewBlockWithHeader(parent), db, n, func(i int, b *core.BlockGen) {
+	blocks, _ := core.GenerateChain(params.TestChainConfig, types.NewBlockWithHeader(parent), ethash.NewFaker(), db, n, func(i int, b *core.BlockGen) {
 		b.SetCoinbase(common.Address{0: byte(seed), 19: byte(i)})
 	})
 	headers := make([]*types.Header, len(blocks))
diff --git a/light/odr_test.go b/light/odr_test.go
index e6afb1a48..c0eb409f9 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -242,7 +242,7 @@ func testChainOdr(t *testing.T, protocol int, fn odrTestFn) {
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
 	blockchain, _ := core.NewBlockChain(sdb, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{})
-	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, sdb, 4, testChainGen)
+	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		t.Fatal(err)
 	}
diff --git a/light/trie_test.go b/light/trie_test.go
index 5f45c01af..d99664718 100644
--- a/light/trie_test.go
+++ b/light/trie_test.go
@@ -41,7 +41,7 @@ func TestNodeIterator(t *testing.T) {
 	)
 	gspec.MustCommit(lightdb)
 	blockchain, _ := core.NewBlockChain(fulldb, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{})
-	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, fulldb, 4, testChainGen)
+	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), fulldb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
 	}
diff --git a/light/txpool_test.go b/light/txpool_test.go
index fe7936ac2..2ef9e0cf5 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -89,7 +89,7 @@ func TestTxPool(t *testing.T) {
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
 	blockchain, _ := core.NewBlockChain(sdb, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{})
-	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, sdb, poolTestBlocks, txPoolTestChainGen)
+	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, poolTestBlocks, txPoolTestChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
 	}