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

6 files changed, 11 insertions, 7 deletions

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)
 	}