diff --git a/core/block_processor_test.go b/core/block_processor_test.go
index 02524a4c1..e0aa5fb4c 100644
--- a/core/block_processor_test.go
+++ b/core/block_processor_test.go
@@ -14,7 +14,7 @@ func proc() (*BlockProcessor, *ChainManager) {
 	db, _ := ethdb.NewMemDatabase()
 	var mux event.TypeMux
 
-	chainMan := NewChainManager(db, db, &mux)
+	chainMan := NewChainManager(db, db, thePow(), &mux)
 	return NewBlockProcessor(db, db, ezp.New(), nil, chainMan, &mux), chainMan
 }
 
@@ -24,13 +24,13 @@ func TestNumber(t *testing.T) {
 	block1.Header().Number = big.NewInt(3)
 	block1.Header().Time--
 
-	err := bp.ValidateHeader(block1.Header(), chain.Genesis().Header())
+	err := bp.ValidateHeader(block1.Header(), chain.Genesis().Header(), false)
 	if err != BlockNumberErr {
 		t.Errorf("expected block number error %v", err)
 	}
 
 	block1 = chain.NewBlock(common.Address{})
-	err = bp.ValidateHeader(block1.Header(), chain.Genesis().Header())
+	err = bp.ValidateHeader(block1.Header(), chain.Genesis().Header(), false)
 	if err == BlockNumberErr {
 		t.Errorf("didn't expect block number error")
 	}
diff --git a/core/chain_makers.go b/core/chain_makers.go
index acf7b39cc..44f17cc33 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -109,7 +109,7 @@ func makeChain(bman *BlockProcessor, parent *types.Block, max int, db common.Dat
 // Effectively a fork factory
 func newChainManager(block *types.Block, eventMux *event.TypeMux, db common.Database) *ChainManager {
 	genesis := GenesisBlock(db)
-	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: eventMux}
+	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: eventMux, pow: FakePow{}}
 	bc.txState = state.ManageState(state.New(genesis.Root(), db))
 	bc.futureBlocks = NewBlockCache(1000)
 	if block == nil {
diff --git a/core/chain_manager_test.go b/core/chain_manager_test.go
index b5155e223..56bef24f3 100644
--- a/core/chain_manager_test.go
+++ b/core/chain_manager_test.go
@@ -9,11 +9,13 @@ import (
 	"strconv"
 	"testing"
 
+	"github.com/ethereum/ethash"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/pow"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
@@ -21,6 +23,11 @@ func init() {
 	runtime.GOMAXPROCS(runtime.NumCPU())
 }
 
+func thePow() pow.PoW {
+	pow, _ := ethash.NewForTesting()
+	return pow
+}
+
 // Test fork of length N starting from block i
 func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big.Int)) {
 	// switch databases to process the new chain
@@ -259,7 +266,7 @@ func TestChainInsertions(t *testing.T) {
 	}
 
 	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, &eventMux)
+	chainMan := NewChainManager(db, db, thePow(), &eventMux)
 	txPool := NewTxPool(&eventMux, chainMan.State, func() *big.Int { return big.NewInt(100000000) })
 	blockMan := NewBlockProcessor(db, db, nil, txPool, chainMan, &eventMux)
 	chainMan.SetProcessor(blockMan)
@@ -305,7 +312,7 @@ func TestChainMultipleInsertions(t *testing.T) {
 		}
 	}
 	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, &eventMux)
+	chainMan := NewChainManager(db, db, thePow(), &eventMux)
 	txPool := NewTxPool(&eventMux, chainMan.State, func() *big.Int { return big.NewInt(100000000) })
 	blockMan := NewBlockProcessor(db, db, nil, txPool, chainMan, &eventMux)
 	chainMan.SetProcessor(blockMan)
@@ -334,7 +341,7 @@ func TestGetAncestors(t *testing.T) {
 
 	db, _ := ethdb.NewMemDatabase()
 	var eventMux event.TypeMux
-	chainMan := NewChainManager(db, db, &eventMux)
+	chainMan := NewChainManager(db, db, thePow(), &eventMux)
 	chain, err := loadChain("valid1", t)
 	if err != nil {
 		fmt.Println(err)
@@ -372,7 +379,7 @@ func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block
 
 func chm(genesis *types.Block, db common.Database) *ChainManager {
 	var eventMux event.TypeMux
-	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: &eventMux}
+	bc := &ChainManager{blockDb: db, stateDb: db, genesisBlock: genesis, eventMux: &eventMux, pow: FakePow{}}
 	bc.cache = NewBlockCache(100)
 	bc.futureBlocks = NewBlockCache(100)
 	bc.processor = bproc{}