From 63c56cca5c3fac51f0b46135d550c161ced9f331 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Tue, 14 Jan 2020 15:32:07 +0300
Subject: [PATCH 1/5] core: refactor out Block, BlockBase and Header structs

See #597.
---
 cli/server/server.go                |  3 +-
 pkg/consensus/block.go              |  4 +--
 pkg/consensus/consensus.go          |  5 ++--
 pkg/core/{ => block}/block.go       |  6 ++--
 pkg/core/{ => block}/block_base.go  |  2 +-
 pkg/core/{ => block}/block_test.go  |  8 +++---
 pkg/core/{ => block}/header.go      |  2 +-
 pkg/core/{ => block}/header_test.go |  2 +-
 pkg/core/block/helper_test.go       | 44 +++++++++++++++++++++++++++++
 pkg/core/blockchain.go              | 29 ++++++++++---------
 pkg/core/blockchain_test.go         |  3 +-
 pkg/core/blockchainer.go            | 11 ++++----
 pkg/core/dao.go                     |  9 +++---
 pkg/core/dao_test.go                | 15 +++++-----
 pkg/core/helper_test.go             | 41 +++++++++++++++++++++------
 pkg/core/interop_neo_test.go        |  3 +-
 pkg/core/interop_system.go          | 15 +++++-----
 pkg/core/interops.go                |  5 ++--
 pkg/core/util.go                    | 13 +++++----
 pkg/network/blockqueue.go           |  5 ++--
 pkg/network/blockqueue_test.go      |  6 ++--
 pkg/network/helper_test.go          | 11 ++++----
 pkg/network/message.go              |  4 +--
 pkg/network/payload/headers.go      |  8 +++---
 pkg/network/payload/headers_test.go |  8 +++---
 pkg/network/payload/merkleblock.go  |  8 +++---
 pkg/network/server.go               |  9 +++---
 pkg/rpc/server_helper_test.go       |  7 +++--
 pkg/rpc/wrappers/block.go           |  7 +++--
 pkg/rpc/wrappers/tx_raw_output.go   |  3 +-
 30 files changed, 190 insertions(+), 106 deletions(-)
 rename pkg/core/{ => block}/block.go (96%)
 rename pkg/core/{ => block}/block_base.go (99%)
 rename pkg/core/{ => block}/block_test.go (99%)
 rename pkg/core/{ => block}/header.go (97%)
 rename pkg/core/{ => block}/header_test.go (99%)
 create mode 100644 pkg/core/block/helper_test.go

diff --git a/cli/server/server.go b/cli/server/server.go
index 42a5a7259..f560a245c 100644
--- a/cli/server/server.go
+++ b/cli/server/server.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/encoding/address"
 	"github.com/CityOfZion/neo-go/pkg/io"
@@ -268,7 +269,7 @@ func restoreDB(ctx *cli.Context) error {
 	}
 	for ; i < skip+count; i++ {
 		bytes, err := readBlock(reader)
-		block := &core.Block{}
+		block := &block.Block{}
 		newReader := io.NewBinReaderFromBuf(bytes)
 		block.DecodeBinary(newReader)
 		if err != nil {
diff --git a/pkg/consensus/block.go b/pkg/consensus/block.go
index 6d9c6dc27..f71f4bfb5 100644
--- a/pkg/consensus/block.go
+++ b/pkg/consensus/block.go
@@ -1,7 +1,7 @@
 package consensus
 
 import (
-	"github.com/CityOfZion/neo-go/pkg/core"
+	coreb "github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/nspcc-dev/dbft/block"
@@ -11,7 +11,7 @@ import (
 // neoBlock is a wrapper of core.Block which implements
 // methods necessary for dBFT library.
 type neoBlock struct {
-	core.Block
+	coreb.Block
 
 	signature []byte
 }
diff --git a/pkg/consensus/consensus.go b/pkg/consensus/consensus.go
index 6aebda543..8f96d8d5b 100644
--- a/pkg/consensus/consensus.go
+++ b/pkg/consensus/consensus.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	coreb "github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
@@ -67,7 +68,7 @@ type Config struct {
 	Broadcast func(p *Payload)
 	// RelayBlock is a callback that is called to notify server
 	// about the new block that needs to be broadcasted.
-	RelayBlock func(b *core.Block)
+	RelayBlock func(b *coreb.Block)
 	// Chain is a core.Blockchainer instance.
 	Chain core.Blockchainer
 	// RequestTx is a callback to which will be called
@@ -285,7 +286,7 @@ func (s *service) processBlock(b block.Block) {
 	}
 }
 
-func (s *service) getBlockWitness(b *core.Block) *transaction.Witness {
+func (s *service) getBlockWitness(b *coreb.Block) *transaction.Witness {
 	dctx := s.dbft.Context
 	pubs := convertKeys(dctx.Validators)
 	sigs := make(map[*keys.PublicKey][]byte)
diff --git a/pkg/core/block.go b/pkg/core/block/block.go
similarity index 96%
rename from pkg/core/block.go
rename to pkg/core/block/block.go
index a7e2b4791..3077095c7 100644
--- a/pkg/core/block.go
+++ b/pkg/core/block/block.go
@@ -1,4 +1,4 @@
-package core
+package block
 
 import (
 	"errors"
@@ -39,8 +39,8 @@ func merkleTreeFromTransactions(txes []*transaction.Transaction) (*hash.MerkleTr
 	return hash.NewMerkleTree(hashes)
 }
 
-// rebuildMerkleRoot rebuilds the merkleroot of the block.
-func (b *Block) rebuildMerkleRoot() error {
+// RebuildMerkleRoot rebuilds the merkleroot of the block.
+func (b *Block) RebuildMerkleRoot() error {
 	merkle, err := merkleTreeFromTransactions(b.Transactions)
 	if err != nil {
 		return err
diff --git a/pkg/core/block_base.go b/pkg/core/block/block_base.go
similarity index 99%
rename from pkg/core/block_base.go
rename to pkg/core/block/block_base.go
index 9e6c1d0b5..404701059 100644
--- a/pkg/core/block_base.go
+++ b/pkg/core/block/block_base.go
@@ -1,4 +1,4 @@
-package core
+package block
 
 import (
 	"fmt"
diff --git a/pkg/core/block_test.go b/pkg/core/block/block_test.go
similarity index 99%
rename from pkg/core/block_test.go
rename to pkg/core/block/block_test.go
index 82118b6ea..42355e9c0 100644
--- a/pkg/core/block_test.go
+++ b/pkg/core/block/block_test.go
@@ -1,4 +1,4 @@
-package core
+package block
 
 import (
 	"encoding/hex"
@@ -108,21 +108,21 @@ func TestHashBlockEqualsHashHeader(t *testing.T) {
 func TestBlockVerify(t *testing.T) {
 	block := newDumbBlock()
 	assert.NotNil(t, block.Verify())
-	assert.Nil(t, block.rebuildMerkleRoot())
+	assert.Nil(t, block.RebuildMerkleRoot())
 	assert.Nil(t, block.Verify())
 
 	block.Transactions = []*transaction.Transaction{
 		{Type: transaction.IssueType},
 		{Type: transaction.MinerType},
 	}
-	assert.NoError(t, block.rebuildMerkleRoot())
+	assert.NoError(t, block.RebuildMerkleRoot())
 	assert.NotNil(t, block.Verify())
 
 	block.Transactions = []*transaction.Transaction{
 		{Type: transaction.MinerType},
 		{Type: transaction.MinerType},
 	}
-	assert.NoError(t, block.rebuildMerkleRoot())
+	assert.NoError(t, block.RebuildMerkleRoot())
 	assert.NotNil(t, block.Verify())
 	block.Transactions = []*transaction.Transaction{
 		{Type: transaction.MinerType},
diff --git a/pkg/core/header.go b/pkg/core/block/header.go
similarity index 97%
rename from pkg/core/header.go
rename to pkg/core/block/header.go
index e3bf50824..5f9060f3d 100644
--- a/pkg/core/header.go
+++ b/pkg/core/block/header.go
@@ -1,4 +1,4 @@
-package core
+package block
 
 import (
 	"fmt"
diff --git a/pkg/core/header_test.go b/pkg/core/block/header_test.go
similarity index 99%
rename from pkg/core/header_test.go
rename to pkg/core/block/header_test.go
index ed35c6f73..020afcbda 100644
--- a/pkg/core/header_test.go
+++ b/pkg/core/block/header_test.go
@@ -1,4 +1,4 @@
-package core
+package block
 
 import (
 	"testing"
diff --git a/pkg/core/block/helper_test.go b/pkg/core/block/helper_test.go
new file mode 100644
index 000000000..31a8f29d8
--- /dev/null
+++ b/pkg/core/block/helper_test.go
@@ -0,0 +1,44 @@
+package block
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/io"
+)
+
+func getDecodedBlock(t *testing.T, i int) *Block {
+	data, err := getBlockData(i)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b, err := hex.DecodeString(data["raw"].(string))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	block := &Block{}
+	r := io.NewBinReaderFromBuf(b)
+	block.DecodeBinary(r)
+	if r.Err != nil {
+		t.Fatal(r.Err)
+	}
+
+	return block
+}
+
+func getBlockData(i int) (map[string]interface{}, error) {
+	b, err := ioutil.ReadFile(fmt.Sprintf("../test_data/block_%d.json", i))
+	if err != nil {
+		return nil, err
+	}
+	var data map[string]interface{}
+	if err := json.Unmarshal(b, &data); err != nil {
+		return nil, err
+	}
+	return data, err
+}
diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index 69cb4f9b8..cd0da4930 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -179,7 +180,7 @@ func (bc *Blockchain) init() error {
 			targetHash = genesisBlock.Hash()
 			bc.headerList.Add(targetHash)
 		}
-		headers := make([]*Header, 0)
+		headers := make([]*block.Header, 0)
 
 		for hash != targetHash {
 			header, err := bc.GetHeader(hash)
@@ -242,7 +243,7 @@ func (bc *Blockchain) Close() {
 
 // AddBlock accepts successive block for the Blockchain, verifies it and
 // stores internally. Eventually it will be persisted to the backing storage.
-func (bc *Blockchain) AddBlock(block *Block) error {
+func (bc *Blockchain) AddBlock(block *block.Block) error {
 	expectedHeight := bc.BlockHeight() + 1
 	if expectedHeight != block.Index {
 		return fmt.Errorf("expected block %d, but passed block %d", expectedHeight, block.Index)
@@ -276,7 +277,7 @@ func (bc *Blockchain) AddBlock(block *Block) error {
 
 // AddHeaders processes the given headers and add them to the
 // HeaderHashList.
-func (bc *Blockchain) AddHeaders(headers ...*Header) (err error) {
+func (bc *Blockchain) AddHeaders(headers ...*block.Header) (err error) {
 	var (
 		start = time.Now()
 		batch = bc.dao.store.Batch()
@@ -321,7 +322,7 @@ func (bc *Blockchain) AddHeaders(headers ...*Header) (err error) {
 
 // processHeader processes the given header. Note that this is only thread safe
 // if executed in headers operation.
-func (bc *Blockchain) processHeader(h *Header, batch storage.Batch, headerList *HeaderHashList) error {
+func (bc *Blockchain) processHeader(h *block.Header, batch storage.Batch, headerList *HeaderHashList) error {
 	headerList.Add(h.Hash())
 
 	buf := io.NewBufBinWriter()
@@ -352,7 +353,7 @@ func (bc *Blockchain) processHeader(h *Header, batch storage.Batch, headerList *
 // project. This for the sake of development speed and understanding of what
 // is happening here, quite allot as you can see :). If things are wired together
 // and all tests are in place, we can make a more optimized and cleaner implementation.
-func (bc *Blockchain) storeBlock(block *Block) error {
+func (bc *Blockchain) storeBlock(block *block.Block) error {
 	cache := newCachedDao(bc.dao.store)
 	if err := cache.StoreAsBlock(block, 0); err != nil {
 		return err
@@ -756,10 +757,10 @@ func (bc *Blockchain) GetStorageItems(hash util.Uint160) (map[string]*state.Stor
 }
 
 // GetBlock returns a Block by the given hash.
-func (bc *Blockchain) GetBlock(hash util.Uint256) (*Block, error) {
+func (bc *Blockchain) GetBlock(hash util.Uint256) (*block.Block, error) {
 	topBlock := bc.topBlock.Load()
 	if topBlock != nil {
-		if tb, ok := topBlock.(*Block); ok && tb.Hash().Equals(hash) {
+		if tb, ok := topBlock.(*block.Block); ok && tb.Hash().Equals(hash) {
 			return tb, nil
 		}
 	}
@@ -782,10 +783,10 @@ func (bc *Blockchain) GetBlock(hash util.Uint256) (*Block, error) {
 }
 
 // GetHeader returns data block header identified with the given hash value.
-func (bc *Blockchain) GetHeader(hash util.Uint256) (*Header, error) {
+func (bc *Blockchain) GetHeader(hash util.Uint256) (*block.Header, error) {
 	topBlock := bc.topBlock.Load()
 	if topBlock != nil {
-		if tb, ok := topBlock.(*Block); ok && tb.Hash().Equals(hash) {
+		if tb, ok := topBlock.(*block.Block); ok && tb.Hash().Equals(hash) {
 			return tb.Header(), nil
 		}
 	}
@@ -955,7 +956,7 @@ func (bc *Blockchain) GetMemPool() MemPool {
 }
 
 // VerifyBlock verifies block against its current state.
-func (bc *Blockchain) VerifyBlock(block *Block) error {
+func (bc *Blockchain) VerifyBlock(block *block.Block) error {
 	prevHeader, err := bc.GetHeader(block.PrevHash)
 	if err != nil {
 		return errors.Wrap(err, "unable to get previous header")
@@ -973,7 +974,7 @@ func (bc *Blockchain) VerifyBlock(block *Block) error {
 // is used for easy interop access and can be omitted for transactions that are
 // not yet added into any block.
 // Golang implementation of Verify method in C# (https://github.com/neo-project/neo/blob/master/neo/Network/P2P/Payloads/Transaction.cs#L270).
-func (bc *Blockchain) VerifyTx(t *transaction.Transaction, block *Block) error {
+func (bc *Blockchain) VerifyTx(t *transaction.Transaction, block *block.Block) error {
 	if io.GetVarSize(t) > transaction.MaxTransactionSize {
 		return errors.Errorf("invalid transaction size = %d. It shoud be less then MaxTransactionSize = %d", io.GetVarSize(t), transaction.MaxTransactionSize)
 	}
@@ -1440,7 +1441,7 @@ func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transa
 // not yet added into any block.
 // Golang implementation of VerifyWitnesses method in C# (https://github.com/neo-project/neo/blob/master/neo/SmartContract/Helper.cs#L87).
 // Unfortunately the IVerifiable interface could not be implemented because we can't move the References method in blockchain.go to the transaction.go file.
-func (bc *Blockchain) verifyTxWitnesses(t *transaction.Transaction, block *Block) error {
+func (bc *Blockchain) verifyTxWitnesses(t *transaction.Transaction, block *block.Block) error {
 	hashes, err := bc.GetScriptHashesForVerifying(t)
 	if err != nil {
 		return err
@@ -1465,7 +1466,7 @@ func (bc *Blockchain) verifyTxWitnesses(t *transaction.Transaction, block *Block
 }
 
 // verifyBlockWitnesses is a block-specific implementation of VerifyWitnesses logic.
-func (bc *Blockchain) verifyBlockWitnesses(block *Block, prevHeader *Header) error {
+func (bc *Blockchain) verifyBlockWitnesses(block *block.Block, prevHeader *block.Header) error {
 	var hash util.Uint160
 	if prevHeader == nil && block.PrevHash.Equals(util.Uint256{}) {
 		hash = block.Script.ScriptHash()
@@ -1487,6 +1488,6 @@ func (bc *Blockchain) secondsPerBlock() int {
 	return bc.config.SecondsPerBlock
 }
 
-func (bc *Blockchain) newInteropContext(trigger byte, s storage.Store, block *Block, tx *transaction.Transaction) *interopContext {
+func (bc *Blockchain) newInteropContext(trigger byte, s storage.Store, block *block.Block, tx *transaction.Transaction) *interopContext {
 	return newInteropContext(trigger, bc, s, block, tx, bc.log)
 }
diff --git a/pkg/core/blockchain_test.go b/pkg/core/blockchain_test.go
index 0fa8b3aae..a35245776 100644
--- a/pkg/core/blockchain_test.go
+++ b/pkg/core/blockchain_test.go
@@ -3,6 +3,7 @@ package core
 import (
 	"testing"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
@@ -38,7 +39,7 @@ func TestAddHeaders(t *testing.T) {
 
 func TestAddBlock(t *testing.T) {
 	bc := newTestChain(t)
-	blocks := []*Block{
+	blocks := []*block.Block{
 		newBlock(1, newMinerTX()),
 		newBlock(2, newMinerTX()),
 		newBlock(3, newMinerTX()),
diff --git a/pkg/core/blockchainer.go b/pkg/core/blockchainer.go
index 8493dec80..fdeaa6072 100644
--- a/pkg/core/blockchainer.go
+++ b/pkg/core/blockchainer.go
@@ -2,6 +2,7 @@ package core
 
 import (
 	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -14,15 +15,15 @@ import (
 // of the blockchain.
 type Blockchainer interface {
 	GetConfig() config.ProtocolConfiguration
-	AddHeaders(...*Header) error
-	AddBlock(*Block) error
+	AddHeaders(...*block.Header) error
+	AddBlock(*block.Block) error
 	BlockHeight() uint32
 	Close()
 	HeaderHeight() uint32
-	GetBlock(hash util.Uint256) (*Block, error)
+	GetBlock(hash util.Uint256) (*block.Block, error)
 	GetContractState(hash util.Uint160) *state.Contract
 	GetHeaderHash(int) util.Uint256
-	GetHeader(hash util.Uint256) (*Header, error)
+	GetHeader(hash util.Uint256) (*block.Header, error)
 	CurrentHeaderHash() util.Uint256
 	CurrentBlockHash() util.Uint256
 	HasBlock(util.Uint256) bool
@@ -38,6 +39,6 @@ type Blockchainer interface {
 	GetUnspentCoinState(util.Uint256) *UnspentCoinState
 	References(t *transaction.Transaction) map[transaction.Input]*transaction.Output
 	Feer // fee interface
-	VerifyTx(*transaction.Transaction, *Block) error
+	VerifyTx(*transaction.Transaction, *block.Block) error
 	GetMemPool() MemPool
 }
diff --git a/pkg/core/dao.go b/pkg/core/dao.go
index d570d5e3e..4111fba66 100644
--- a/pkg/core/dao.go
+++ b/pkg/core/dao.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"sort"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -358,13 +359,13 @@ func makeStorageItemKey(scripthash util.Uint160, key []byte) []byte {
 // -- other.
 
 // GetBlock returns Block by the given hash if it exists in the store.
-func (dao *dao) GetBlock(hash util.Uint256) (*Block, error) {
+func (dao *dao) GetBlock(hash util.Uint256) (*block.Block, error) {
 	key := storage.AppendPrefix(storage.DataBlock, hash.BytesLE())
 	b, err := dao.store.Get(key)
 	if err != nil {
 		return nil, err
 	}
-	block, err := NewBlockFromTrimmedBytes(b)
+	block, err := block.NewBlockFromTrimmedBytes(b)
 	if err != nil {
 		return nil, err
 	}
@@ -486,7 +487,7 @@ func (dao *dao) HasTransaction(hash util.Uint256) bool {
 }
 
 // StoreAsBlock stores the given block as DataBlock.
-func (dao *dao) StoreAsBlock(block *Block, sysFee uint32) error {
+func (dao *dao) StoreAsBlock(block *block.Block, sysFee uint32) error {
 	var (
 		key = storage.AppendPrefix(storage.DataBlock, block.Hash().BytesLE())
 		buf = io.NewBufBinWriter()
@@ -505,7 +506,7 @@ func (dao *dao) StoreAsBlock(block *Block, sysFee uint32) error {
 }
 
 // StoreAsCurrentBlock stores the given block witch prefix SYSCurrentBlock.
-func (dao *dao) StoreAsCurrentBlock(block *Block) error {
+func (dao *dao) StoreAsCurrentBlock(block *block.Block) error {
 	buf := io.NewBufBinWriter()
 	h := block.Hash()
 	h.EncodeBinary(buf.BinWriter)
diff --git a/pkg/core/dao_test.go b/pkg/core/dao_test.go
index d747ddf19..cf06aa757 100644
--- a/pkg/core/dao_test.go
+++ b/pkg/core/dao_test.go
@@ -3,6 +3,7 @@ package core
 import (
 	"testing"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -260,16 +261,16 @@ func TestGetBlock_NotExists(t *testing.T) {
 
 func TestPutGetBlock(t *testing.T) {
 	dao := newDao(storage.NewMemoryStore())
-	block := &Block{
-		BlockBase: BlockBase{
+	b := &block.Block{
+		BlockBase: block.BlockBase{
 			Script: transaction.Witness{
 				VerificationScript: []byte{byte(opcode.PUSH1)},
 				InvocationScript:   []byte{byte(opcode.NOP)},
 			},
 		},
 	}
-	hash := block.Hash()
-	err := dao.StoreAsBlock(block, 0)
+	hash := b.Hash()
+	err := dao.StoreAsBlock(b, 0)
 	require.NoError(t, err)
 	gotBlock, err := dao.GetBlock(hash)
 	require.NoError(t, err)
@@ -301,15 +302,15 @@ func TestGetCurrentHeaderHeight_NoHeader(t *testing.T) {
 
 func TestGetCurrentHeaderHeight_Store(t *testing.T) {
 	dao := newDao(storage.NewMemoryStore())
-	block := &Block{
-		BlockBase: BlockBase{
+	b := &block.Block{
+		BlockBase: block.BlockBase{
 			Script: transaction.Witness{
 				VerificationScript: []byte{byte(opcode.PUSH1)},
 				InvocationScript:   []byte{byte(opcode.NOP)},
 			},
 		},
 	}
-	err := dao.StoreAsCurrentBlock(block)
+	err := dao.StoreAsCurrentBlock(b)
 	require.NoError(t, err)
 	height, err := dao.GetCurrentBlockHeight()
 	require.NoError(t, err)
diff --git a/pkg/core/helper_test.go b/pkg/core/helper_test.go
index f750af78f..9a452ffc9 100644
--- a/pkg/core/helper_test.go
+++ b/pkg/core/helper_test.go
@@ -9,8 +9,10 @@ import (
 	"time"
 
 	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/CityOfZion/neo-go/pkg/smartcontract"
@@ -49,7 +51,7 @@ func newTestChain(t *testing.T) *Blockchain {
 	return chain
 }
 
-func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
+func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
 	validators, _ := getValidators(unitTestNetCfg.ProtocolConfiguration)
 	vlen := len(validators)
 	valScript, _ := smartcontract.CreateMultiSigRedeemScript(
@@ -59,8 +61,8 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
 	witness := transaction.Witness{
 		VerificationScript: valScript,
 	}
-	b := &Block{
-		BlockBase: BlockBase{
+	b := &block.Block{
+		BlockBase: block.BlockBase{
 			Version:       0,
 			PrevHash:      newBlockPrevHash,
 			Timestamp:     uint32(time.Now().UTC().Unix()) + index,
@@ -71,8 +73,7 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
 		},
 		Transactions: txs,
 	}
-	_ = b.rebuildMerkleRoot()
-	b.createHash()
+	_ = b.RebuildMerkleRoot()
 	newBlockPrevHash = b.Hash()
 
 	invScript := make([]byte, 0)
@@ -93,8 +94,8 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
 	return b
 }
 
-func makeBlocks(n int) []*Block {
-	blocks := make([]*Block, n)
+func makeBlocks(n int) []*block.Block {
+	blocks := make([]*block.Block, n)
 	for i := 0; i < n; i++ {
 		blocks[i] = newBlock(uint32(i+1), newMinerTX())
 	}
@@ -108,7 +109,7 @@ func newMinerTX() *transaction.Transaction {
 	}
 }
 
-func getDecodedBlock(t *testing.T, i int) *Block {
+func getDecodedBlock(t *testing.T, i int) *block.Block {
 	data, err := getBlockData(i)
 	if err != nil {
 		t.Fatal(err)
@@ -119,7 +120,7 @@ func getDecodedBlock(t *testing.T, i int) *Block {
 		t.Fatal(err)
 	}
 
-	block := &Block{}
+	block := &block.Block{}
 	r := io.NewBinReaderFromBuf(b)
 	block.DecodeBinary(r)
 	if r.Err != nil {
@@ -140,3 +141,25 @@ func getBlockData(i int) (map[string]interface{}, error) {
 	}
 	return data, err
 }
+
+func newDumbBlock() *block.Block {
+	return &block.Block{
+		BlockBase: block.BlockBase{
+			Version:       0,
+			PrevHash:      hash.Sha256([]byte("a")),
+			MerkleRoot:    hash.Sha256([]byte("b")),
+			Timestamp:     uint32(100500),
+			Index:         1,
+			ConsensusData: 1111,
+			NextConsensus: hash.Hash160([]byte("a")),
+			Script: transaction.Witness{
+				VerificationScript: []byte{0x51}, // PUSH1
+				InvocationScript:   []byte{0x61}, // NOP
+			},
+		},
+		Transactions: []*transaction.Transaction{
+			{Type: transaction.MinerType},
+			{Type: transaction.IssueType},
+		},
+	}
+}
diff --git a/pkg/core/interop_neo_test.go b/pkg/core/interop_neo_test.go
index 39c43a714..f55a95cf9 100644
--- a/pkg/core/interop_neo_test.go
+++ b/pkg/core/interop_neo_test.go
@@ -4,6 +4,7 @@ import (
 	"math/big"
 	"testing"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -451,7 +452,7 @@ func TestAssetGetPrecision(t *testing.T) {
 
 // Helper functions to create VM, InteropContext, TX, Account, Contract, Asset.
 
-func createVMAndPushBlock(t *testing.T) (*vm.VM, *Block, *interopContext, *Blockchain) {
+func createVMAndPushBlock(t *testing.T) (*vm.VM, *block.Block, *interopContext, *Blockchain) {
 	v := vm.New()
 	block := newDumbBlock()
 	chain := newTestChain(t)
diff --git a/pkg/core/interop_system.go b/pkg/core/interop_system.go
index b96b5a0ec..9d8c930a8 100644
--- a/pkg/core/interop_system.go
+++ b/pkg/core/interop_system.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"math"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
@@ -132,11 +133,11 @@ func (ic *interopContext) bcGetTransactionHeight(v *vm.VM) error {
 // popHeaderFromVM returns pointer to Header or error. It's main feature is
 // proper treatment of Block structure, because C# code implicitly assumes
 // that header APIs can also operate on blocks.
-func popHeaderFromVM(v *vm.VM) (*Header, error) {
+func popHeaderFromVM(v *vm.VM) (*block.Header, error) {
 	iface := v.Estack().Pop().Value()
-	header, ok := iface.(*Header)
+	header, ok := iface.(*block.Header)
 	if !ok {
-		block, ok := iface.(*Block)
+		block, ok := iface.(*block.Block)
 		if !ok {
 			return nil, errors.New("value is not a header or block")
 		}
@@ -188,7 +189,7 @@ func (ic *interopContext) headerGetTimestamp(v *vm.VM) error {
 // blockGetTransactionCount returns transactions count in the given block.
 func (ic *interopContext) blockGetTransactionCount(v *vm.VM) error {
 	blockInterface := v.Estack().Pop().Value()
-	block, ok := blockInterface.(*Block)
+	block, ok := blockInterface.(*block.Block)
 	if !ok {
 		return errors.New("value is not a block")
 	}
@@ -199,7 +200,7 @@ func (ic *interopContext) blockGetTransactionCount(v *vm.VM) error {
 // blockGetTransactions returns transactions from the given block.
 func (ic *interopContext) blockGetTransactions(v *vm.VM) error {
 	blockInterface := v.Estack().Pop().Value()
-	block, ok := blockInterface.(*Block)
+	block, ok := blockInterface.(*block.Block)
 	if !ok {
 		return errors.New("value is not a block")
 	}
@@ -218,7 +219,7 @@ func (ic *interopContext) blockGetTransactions(v *vm.VM) error {
 // block.
 func (ic *interopContext) blockGetTransaction(v *vm.VM) error {
 	blockInterface := v.Estack().Pop().Value()
-	block, ok := blockInterface.(*Block)
+	block, ok := blockInterface.(*block.Block)
 	if !ok {
 		return errors.New("value is not a block")
 	}
@@ -359,7 +360,7 @@ func (ic *interopContext) runtimeLog(v *vm.VM) error {
 // runtimeGetTime returns timestamp of the block being verified, or the latest
 // one in the blockchain if no block is given to interopContext.
 func (ic *interopContext) runtimeGetTime(v *vm.VM) error {
-	var header *Header
+	var header *block.Header
 	if ic.block == nil {
 		var err error
 		header, err = ic.bc.GetHeader(ic.bc.CurrentBlockHash())
diff --git a/pkg/core/interops.go b/pkg/core/interops.go
index bf33b347d..15ee9b994 100644
--- a/pkg/core/interops.go
+++ b/pkg/core/interops.go
@@ -10,6 +10,7 @@ package core
 import (
 	"sort"
 
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -20,14 +21,14 @@ import (
 type interopContext struct {
 	bc            Blockchainer
 	trigger       byte
-	block         *Block
+	block         *block.Block
 	tx            *transaction.Transaction
 	dao           *cachedDao
 	notifications []state.NotificationEvent
 	log           *zap.Logger
 }
 
-func newInteropContext(trigger byte, bc Blockchainer, s storage.Store, block *Block, tx *transaction.Transaction, log *zap.Logger) *interopContext {
+func newInteropContext(trigger byte, bc Blockchainer, s storage.Store, block *block.Block, tx *transaction.Transaction, log *zap.Logger) *interopContext {
 	dao := newCachedDao(s)
 	nes := make([]state.NotificationEvent, 0)
 	return &interopContext{bc, trigger, block, tx, dao, nes, log}
diff --git a/pkg/core/util.go b/pkg/core/util.go
index c553f5ef0..3269035de 100644
--- a/pkg/core/util.go
+++ b/pkg/core/util.go
@@ -4,6 +4,7 @@ import (
 	"time"
 
 	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/crypto/keys"
@@ -13,7 +14,7 @@ import (
 )
 
 // createGenesisBlock creates a genesis block based on the given configuration.
-func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
+func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error) {
 	validators, err := getValidators(cfg)
 	if err != nil {
 		return nil, err
@@ -24,7 +25,7 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
 		return nil, err
 	}
 
-	base := BlockBase{
+	base := block.BlockBase{
 		Version:       0,
 		PrevHash:      util.Uint256{},
 		Timestamp:     uint32(time.Date(2016, 7, 15, 15, 8, 21, 0, time.UTC).Unix()),
@@ -48,7 +49,7 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
 	}
 	scriptOut := hash.Hash160(rawScript)
 
-	block := &Block{
+	b := &block.Block{
 		BlockBase: base,
 		Transactions: []*transaction.Transaction{
 			{
@@ -84,11 +85,11 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
 		},
 	}
 
-	if err = block.rebuildMerkleRoot(); err != nil {
+	if err = b.RebuildMerkleRoot(); err != nil {
 		return nil, err
 	}
 
-	return block, nil
+	return b, nil
 }
 
 func governingTokenTX() *transaction.Transaction {
@@ -167,7 +168,7 @@ func calculateUtilityAmount() util.Fixed8 {
 }
 
 // headerSliceReverse reverses the given slice of *Header.
-func headerSliceReverse(dest []*Header) {
+func headerSliceReverse(dest []*block.Header) {
 	for i, j := 0, len(dest)-1; i < j; i, j = i+1, j-1 {
 		dest[i], dest[j] = dest[j], dest[i]
 	}
diff --git a/pkg/network/blockqueue.go b/pkg/network/blockqueue.go
index bbd9f176a..e26d96629 100644
--- a/pkg/network/blockqueue.go
+++ b/pkg/network/blockqueue.go
@@ -2,6 +2,7 @@ package network
 
 import (
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/Workiva/go-datastructures/queue"
 	"go.uber.org/zap"
 )
@@ -37,7 +38,7 @@ func (bq *blockQueue) run() {
 			if item == nil {
 				break
 			}
-			minblock := item.(*core.Block)
+			minblock := item.(*block.Block)
 			if minblock.Index <= bq.chain.BlockHeight()+1 {
 				_, _ = bq.queue.Get(1)
 				updateBlockQueueLenMetric(bq.length())
@@ -57,7 +58,7 @@ func (bq *blockQueue) run() {
 	}
 }
 
-func (bq *blockQueue) putBlock(block *core.Block) error {
+func (bq *blockQueue) putBlock(block *block.Block) error {
 	if bq.chain.BlockHeight() >= block.Index {
 		// can easily happen when fetching the same blocks from
 		// different peers, thus not considered as error
diff --git a/pkg/network/blockqueue_test.go b/pkg/network/blockqueue_test.go
index f30b47a0a..881759d33 100644
--- a/pkg/network/blockqueue_test.go
+++ b/pkg/network/blockqueue_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/stretchr/testify/assert"
 	"go.uber.org/zap/zaptest"
 )
@@ -13,9 +13,9 @@ func TestBlockQueue(t *testing.T) {
 	chain := &testChain{}
 	// notice, it's not yet running
 	bq := newBlockQueue(0, chain, zaptest.NewLogger(t))
-	blocks := make([]*core.Block, 11)
+	blocks := make([]*block.Block, 11)
 	for i := 1; i < 11; i++ {
-		blocks[i] = &core.Block{BlockBase: core.BlockBase{Index: uint32(i)}}
+		blocks[i] = &block.Block{BlockBase: block.BlockBase{Index: uint32(i)}}
 	}
 	// not the ones expected currently
 	for i := 3; i < 5; i++ {
diff --git a/pkg/network/helper_test.go b/pkg/network/helper_test.go
index 5fdc86e5f..e71fde016 100644
--- a/pkg/network/helper_test.go
+++ b/pkg/network/helper_test.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -43,10 +44,10 @@ func (chain testChain) NetworkFee(t *transaction.Transaction) util.Fixed8 {
 	panic("TODO")
 }
 
-func (chain testChain) AddHeaders(...*core.Header) error {
+func (chain testChain) AddHeaders(...*block.Header) error {
 	panic("TODO")
 }
-func (chain *testChain) AddBlock(block *core.Block) error {
+func (chain *testChain) AddBlock(block *block.Block) error {
 	if block.Index == chain.blockheight+1 {
 		atomic.StoreUint32(&chain.blockheight, block.Index)
 	}
@@ -61,7 +62,7 @@ func (chain *testChain) Close() {
 func (chain testChain) HeaderHeight() uint32 {
 	return 0
 }
-func (chain testChain) GetBlock(hash util.Uint256) (*core.Block, error) {
+func (chain testChain) GetBlock(hash util.Uint256) (*block.Block, error) {
 	panic("TODO")
 }
 func (chain testChain) GetContractState(hash util.Uint160) *state.Contract {
@@ -70,7 +71,7 @@ func (chain testChain) GetContractState(hash util.Uint160) *state.Contract {
 func (chain testChain) GetHeaderHash(int) util.Uint256 {
 	return util.Uint256{}
 }
-func (chain testChain) GetHeader(hash util.Uint256) (*core.Header, error) {
+func (chain testChain) GetHeader(hash util.Uint256) (*block.Header, error) {
 	panic("TODO")
 }
 
@@ -123,7 +124,7 @@ func (chain testChain) IsLowPriority(*transaction.Transaction) bool {
 	panic("TODO")
 }
 
-func (chain testChain) VerifyTx(*transaction.Transaction, *core.Block) error {
+func (chain testChain) VerifyTx(*transaction.Transaction, *block.Block) error {
 	panic("TODO")
 }
 
diff --git a/pkg/network/message.go b/pkg/network/message.go
index 087724967..973dee330 100644
--- a/pkg/network/message.go
+++ b/pkg/network/message.go
@@ -7,7 +7,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/consensus"
-	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/crypto/hash"
 	"github.com/CityOfZion/neo-go/pkg/io"
@@ -184,7 +184,7 @@ func (m *Message) decodePayload(br *io.BinReader) error {
 	case CMDAddr:
 		p = &payload.AddressList{}
 	case CMDBlock:
-		p = &core.Block{}
+		p = &block.Block{}
 	case CMDConsensus:
 		p = &consensus.Payload{}
 	case CMDGetBlocks:
diff --git a/pkg/network/payload/headers.go b/pkg/network/payload/headers.go
index 57160c190..1b0ed7fd4 100644
--- a/pkg/network/payload/headers.go
+++ b/pkg/network/payload/headers.go
@@ -1,14 +1,14 @@
 package payload
 
 import (
-	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/pkg/errors"
 )
 
 // Headers payload.
 type Headers struct {
-	Hdrs []*core.Header
+	Hdrs []*block.Header
 }
 
 // Users can at most request 2k header.
@@ -30,10 +30,10 @@ func (p *Headers) DecodeBinary(br *io.BinReader) {
 		lenHeaders = MaxHeadersAllowed
 	}
 
-	p.Hdrs = make([]*core.Header, lenHeaders)
+	p.Hdrs = make([]*block.Header, lenHeaders)
 
 	for i := 0; i < int(lenHeaders); i++ {
-		header := &core.Header{}
+		header := &block.Header{}
 		header.DecodeBinary(br)
 		p.Hdrs[i] = header
 	}
diff --git a/pkg/network/payload/headers_test.go b/pkg/network/payload/headers_test.go
index 22762cc0e..f9fa957d0 100644
--- a/pkg/network/payload/headers_test.go
+++ b/pkg/network/payload/headers_test.go
@@ -4,7 +4,7 @@ import (
 	"encoding/hex"
 	"testing"
 
-	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/stretchr/testify/assert"
@@ -26,11 +26,11 @@ func TestHeadersEncodeDecode(t *testing.T) {
 }
 
 func newTestHeaders(n int) *Headers {
-	headers := &Headers{Hdrs: make([]*core.Header, n)}
+	headers := &Headers{Hdrs: make([]*block.Header, n)}
 
 	for i := range headers.Hdrs {
-		headers.Hdrs[i] = &core.Header{
-			BlockBase: core.BlockBase{
+		headers.Hdrs[i] = &block.Header{
+			BlockBase: block.BlockBase{
 				Index: uint32(i + 1),
 				Script: transaction.Witness{
 					InvocationScript:   []byte{0x0},
diff --git a/pkg/network/payload/merkleblock.go b/pkg/network/payload/merkleblock.go
index 410e2b749..9759a853c 100644
--- a/pkg/network/payload/merkleblock.go
+++ b/pkg/network/payload/merkleblock.go
@@ -1,14 +1,14 @@
 package payload
 
 import (
-	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
 // MerkleBlock represents a merkle block packet payload.
 type MerkleBlock struct {
-	*core.BlockBase
+	*block.BlockBase
 	TxCount int
 	Hashes  []util.Uint256
 	Flags   []byte
@@ -16,7 +16,7 @@ type MerkleBlock struct {
 
 // DecodeBinary implements Serializable interface.
 func (m *MerkleBlock) DecodeBinary(br *io.BinReader) {
-	m.BlockBase = &core.BlockBase{}
+	m.BlockBase = &block.BlockBase{}
 	m.BlockBase.DecodeBinary(br)
 
 	m.TxCount = int(br.ReadVarUint())
@@ -26,7 +26,7 @@ func (m *MerkleBlock) DecodeBinary(br *io.BinReader) {
 
 // EncodeBinary implements Serializable interface.
 func (m *MerkleBlock) EncodeBinary(bw *io.BinWriter) {
-	m.BlockBase = &core.BlockBase{}
+	m.BlockBase = &block.BlockBase{}
 	m.BlockBase.EncodeBinary(bw)
 
 	bw.WriteVarUint(uint64(m.TxCount))
diff --git a/pkg/network/server.go b/pkg/network/server.go
index 9eabb5e7e..dbda99c9f 100644
--- a/pkg/network/server.go
+++ b/pkg/network/server.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/pkg/consensus"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/network/payload"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -400,7 +401,7 @@ func (s *Server) handleHeadersCmd(p Peer, headers *payload.Headers) {
 }
 
 // handleBlockCmd processes the received block received from its peer.
-func (s *Server) handleBlockCmd(p Peer, block *core.Block) error {
+func (s *Server) handleBlockCmd(p Peer, block *block.Block) error {
 	return s.bQueue.putBlock(block)
 }
 
@@ -505,7 +506,7 @@ func (s *Server) handleGetHeadersCmd(p Peer, gh *payload.GetBlocks) error {
 		return err
 	}
 	resp := payload.Headers{}
-	resp.Hdrs = make([]*core.Header, 0, payload.MaxHeadersAllowed)
+	resp.Hdrs = make([]*block.Header, 0, payload.MaxHeadersAllowed)
 	for i := start.Index + 1; i < start.Index+1+payload.MaxHeadersAllowed; i++ {
 		hash := s.chain.GetHeaderHash(int(i))
 		if hash.Equals(util.Uint256{}) || hash.Equals(gh.HashStop) {
@@ -632,7 +633,7 @@ func (s *Server) handleMessage(peer Peer, msg *Message) error {
 			inventory := msg.Payload.(*payload.Inventory)
 			return s.handleInvCmd(peer, inventory)
 		case CMDBlock:
-			block := msg.Payload.(*core.Block)
+			block := msg.Payload.(*block.Block)
 			return s.handleBlockCmd(peer, block)
 		case CMDConsensus:
 			cp := msg.Payload.(*consensus.Payload)
@@ -689,7 +690,7 @@ func (s *Server) relayInventoryCmd(cmd CommandType, t payload.InventoryType, has
 }
 
 // relayBlock tells all the other connected nodes about the given block.
-func (s *Server) relayBlock(b *core.Block) {
+func (s *Server) relayBlock(b *block.Block) {
 	s.relayInventoryCmd(CMDInv, payload.BlockType, b.Hash())
 }
 
diff --git a/pkg/rpc/server_helper_test.go b/pkg/rpc/server_helper_test.go
index 5b0590f69..135e96f8a 100644
--- a/pkg/rpc/server_helper_test.go
+++ b/pkg/rpc/server_helper_test.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/CityOfZion/neo-go/pkg/network"
@@ -193,10 +194,10 @@ func initServerWithInMemoryChain(t *testing.T) (*core.Blockchain, http.HandlerFu
 	nBlocks = br.ReadU32LE()
 	require.Nil(t, br.Err)
 	for i := 0; i < int(nBlocks); i++ {
-		block := &core.Block{}
-		block.DecodeBinary(br)
+		b := &block.Block{}
+		b.DecodeBinary(br)
 		require.Nil(t, br.Err)
-		require.NoError(t, chain.AddBlock(block))
+		require.NoError(t, chain.AddBlock(b))
 	}
 
 	serverConfig := network.NewServerConfig(cfg)
diff --git a/pkg/rpc/wrappers/block.go b/pkg/rpc/wrappers/block.go
index 6c6a6ef56..77cf71bb0 100644
--- a/pkg/rpc/wrappers/block.go
+++ b/pkg/rpc/wrappers/block.go
@@ -2,14 +2,15 @@ package wrappers
 
 import (
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
 type (
 	// Block wrapper used for the representation of
-	// core.Block / core.BlockBase on the RPC Server.
+	// block.Block / block.BlockBase on the RPC Server.
 	Block struct {
-		*core.Block
+		*block.Block
 		Confirmations uint32       `json:"confirmations"`
 		NextBlockHash util.Uint256 `json:"nextblockhash,omitempty"`
 		Hash          util.Uint256 `json:"hash"`
@@ -17,7 +18,7 @@ type (
 )
 
 // NewBlock creates a new Block wrapper.
-func NewBlock(block *core.Block, chain core.Blockchainer) Block {
+func NewBlock(block *block.Block, chain core.Blockchainer) Block {
 	blockWrapper := Block{
 		Block: block,
 		Hash:  block.Hash(),
diff --git a/pkg/rpc/wrappers/tx_raw_output.go b/pkg/rpc/wrappers/tx_raw_output.go
index 7a8a6fcf7..53f3025c9 100644
--- a/pkg/rpc/wrappers/tx_raw_output.go
+++ b/pkg/rpc/wrappers/tx_raw_output.go
@@ -2,6 +2,7 @@ package wrappers
 
 import (
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/block"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -21,7 +22,7 @@ type TransactionOutputRaw struct {
 }
 
 // NewTransactionOutputRaw returns a new ransactionOutputRaw object.
-func NewTransactionOutputRaw(tx *transaction.Transaction, header *core.Header, chain core.Blockchainer) TransactionOutputRaw {
+func NewTransactionOutputRaw(tx *transaction.Transaction, header *block.Header, chain core.Blockchainer) TransactionOutputRaw {
 	// confirmations formula
 	confirmations := int(chain.BlockHeight() - header.BlockBase.Index + 1)
 	// set index position

From 489b88afbba54bcd9d4cd5ca13d5b8e2cfaaee1d Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 15 Jan 2020 11:29:50 +0300
Subject: [PATCH 2/5] block: rename BlockBase to Base

---
 pkg/consensus/block.go              |  4 ++--
 pkg/core/block/block.go             |  8 ++++----
 pkg/core/block/block_base.go        | 24 ++++++++++++------------
 pkg/core/block/block_test.go        |  8 ++++----
 pkg/core/block/header.go            |  6 +++---
 pkg/core/block/header_test.go       |  2 +-
 pkg/core/dao_test.go                |  4 ++--
 pkg/core/helper_test.go             |  4 ++--
 pkg/core/util.go                    |  4 ++--
 pkg/network/blockqueue_test.go      |  2 +-
 pkg/network/payload/headers_test.go |  2 +-
 pkg/network/payload/merkleblock.go  | 10 +++++-----
 pkg/rpc/wrappers/block.go           |  2 +-
 pkg/rpc/wrappers/tx_raw_output.go   |  2 +-
 14 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/pkg/consensus/block.go b/pkg/consensus/block.go
index f71f4bfb5..90824fe9e 100644
--- a/pkg/consensus/block.go
+++ b/pkg/consensus/block.go
@@ -20,7 +20,7 @@ var _ block.Block = (*neoBlock)(nil)
 
 // Sign implements block.Block interface.
 func (n *neoBlock) Sign(key crypto.PrivateKey) error {
-	data := n.BlockBase.GetHashableData()
+	data := n.Base.GetHashableData()
 	sig, err := key.Sign(data[:])
 	if err != nil {
 		return err
@@ -33,7 +33,7 @@ func (n *neoBlock) Sign(key crypto.PrivateKey) error {
 
 // Verify implements block.Block interface.
 func (n *neoBlock) Verify(key crypto.PublicKey, sign []byte) error {
-	data := n.BlockBase.GetHashableData()
+	data := n.Base.GetHashableData()
 	return key.Verify(data, sign)
 }
 
diff --git a/pkg/core/block/block.go b/pkg/core/block/block.go
index 3077095c7..4eb533a8d 100644
--- a/pkg/core/block/block.go
+++ b/pkg/core/block/block.go
@@ -14,7 +14,7 @@ import (
 // Block represents one block in the chain.
 type Block struct {
 	// The base of the block.
-	BlockBase
+	Base
 
 	// Transaction list.
 	Transactions []*transaction.Transaction `json:"tx"`
@@ -26,7 +26,7 @@ type Block struct {
 // Header returns the Header of the Block.
 func (b *Block) Header() *Header {
 	return &Header{
-		BlockBase: b.BlockBase,
+		Base: b.Base,
 	}
 }
 
@@ -126,14 +126,14 @@ func (b *Block) Trim() ([]byte, error) {
 // DecodeBinary decodes the block from the given BinReader, implementing
 // Serializable interface.
 func (b *Block) DecodeBinary(br *io.BinReader) {
-	b.BlockBase.DecodeBinary(br)
+	b.Base.DecodeBinary(br)
 	br.ReadArray(&b.Transactions)
 }
 
 // EncodeBinary encodes the block to the given BinWriter, implementing
 // Serializable interface.
 func (b *Block) EncodeBinary(bw *io.BinWriter) {
-	b.BlockBase.EncodeBinary(bw)
+	b.Base.EncodeBinary(bw)
 	bw.WriteArray(b.Transactions)
 }
 
diff --git a/pkg/core/block/block_base.go b/pkg/core/block/block_base.go
index 404701059..8655ea9ac 100644
--- a/pkg/core/block/block_base.go
+++ b/pkg/core/block/block_base.go
@@ -9,8 +9,8 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
-// BlockBase holds the base info of a block
-type BlockBase struct {
+// Base holds the base info of a block
+type Base struct {
 	// Version of the block.
 	Version uint32 `json:"version"`
 
@@ -47,14 +47,14 @@ type BlockBase struct {
 	verificationHash util.Uint256
 }
 
-// Verify verifies the integrity of the BlockBase.
-func (b *BlockBase) Verify() bool {
+// Verify verifies the integrity of the Base.
+func (b *Base) Verify() bool {
 	// TODO: Need a persisted blockchain for this.
 	return true
 }
 
 // Hash returns the hash of the block.
-func (b *BlockBase) Hash() util.Uint256 {
+func (b *Base) Hash() util.Uint256 {
 	if b.hash.Equals(util.Uint256{}) {
 		b.createHash()
 	}
@@ -62,7 +62,7 @@ func (b *BlockBase) Hash() util.Uint256 {
 }
 
 // VerificationHash returns the hash of the block used to verify it.
-func (b *BlockBase) VerificationHash() util.Uint256 {
+func (b *Base) VerificationHash() util.Uint256 {
 	if b.verificationHash.Equals(util.Uint256{}) {
 		b.createHash()
 	}
@@ -70,7 +70,7 @@ func (b *BlockBase) VerificationHash() util.Uint256 {
 }
 
 // DecodeBinary implements Serializable interface.
-func (b *BlockBase) DecodeBinary(br *io.BinReader) {
+func (b *Base) DecodeBinary(br *io.BinReader) {
 	b.decodeHashableFields(br)
 
 	padding := []byte{0}
@@ -84,14 +84,14 @@ func (b *BlockBase) DecodeBinary(br *io.BinReader) {
 }
 
 // EncodeBinary implements Serializable interface
-func (b *BlockBase) EncodeBinary(bw *io.BinWriter) {
+func (b *Base) EncodeBinary(bw *io.BinWriter) {
 	b.encodeHashableFields(bw)
 	bw.WriteBytes([]byte{1})
 	b.Script.EncodeBinary(bw)
 }
 
 // GetHashableData returns serialized hashable data of the block.
-func (b *BlockBase) GetHashableData() []byte {
+func (b *Base) GetHashableData() []byte {
 	buf := io.NewBufBinWriter()
 	// No error can occure while encoding hashable fields.
 	b.encodeHashableFields(buf.BinWriter)
@@ -105,7 +105,7 @@ func (b *BlockBase) GetHashableData() []byte {
 // version, PrevBlock, MerkleRoot, timestamp, and height, the nonce, NextMiner.
 // Since MerkleRoot already contains the hash value of all transactions,
 // the modification of transaction will influence the hash value of the block.
-func (b *BlockBase) createHash() {
+func (b *Base) createHash() {
 	bb := b.GetHashableData()
 	b.verificationHash = hash.Sha256(bb)
 	b.hash = hash.Sha256(b.verificationHash.BytesBE())
@@ -113,7 +113,7 @@ func (b *BlockBase) createHash() {
 
 // encodeHashableFields will only encode the fields used for hashing.
 // see Hash() for more information about the fields.
-func (b *BlockBase) encodeHashableFields(bw *io.BinWriter) {
+func (b *Base) encodeHashableFields(bw *io.BinWriter) {
 	bw.WriteU32LE(b.Version)
 	bw.WriteBytes(b.PrevHash[:])
 	bw.WriteBytes(b.MerkleRoot[:])
@@ -125,7 +125,7 @@ func (b *BlockBase) encodeHashableFields(bw *io.BinWriter) {
 
 // decodeHashableFields decodes the fields used for hashing.
 // see Hash() for more information about the fields.
-func (b *BlockBase) decodeHashableFields(br *io.BinReader) {
+func (b *Base) decodeHashableFields(br *io.BinReader) {
 	b.Version = br.ReadU32LE()
 	br.ReadBytes(b.PrevHash[:])
 	br.ReadBytes(b.MerkleRoot[:])
diff --git a/pkg/core/block/block_test.go b/pkg/core/block/block_test.go
index 42355e9c0..571e404d3 100644
--- a/pkg/core/block/block_test.go
+++ b/pkg/core/block/block_test.go
@@ -79,7 +79,7 @@ func TestTrimmedBlock(t *testing.T) {
 
 func newDumbBlock() *Block {
 	return &Block{
-		BlockBase: BlockBase{
+		Base: Base{
 			Version:       0,
 			PrevHash:      hash.Sha256([]byte("a")),
 			MerkleRoot:    hash.Sha256([]byte("b")),
@@ -291,9 +291,9 @@ func TestBlockSizeCalculation(t *testing.T) {
 }
 
 func TestBlockCompare(t *testing.T) {
-	b1 := Block{BlockBase: BlockBase{Index: 1}}
-	b2 := Block{BlockBase: BlockBase{Index: 2}}
-	b3 := Block{BlockBase: BlockBase{Index: 3}}
+	b1 := Block{Base: Base{Index: 1}}
+	b2 := Block{Base: Base{Index: 2}}
+	b3 := Block{Base: Base{Index: 3}}
 	assert.Equal(t, 1, b2.Compare(&b1))
 	assert.Equal(t, 0, b2.Compare(&b2))
 	assert.Equal(t, -1, b2.Compare(&b3))
diff --git a/pkg/core/block/header.go b/pkg/core/block/header.go
index 5f9060f3d..98804870c 100644
--- a/pkg/core/block/header.go
+++ b/pkg/core/block/header.go
@@ -9,14 +9,14 @@ import (
 // Header holds the head info of a block.
 type Header struct {
 	// Base of the block.
-	BlockBase
+	Base
 	// Padding that is fixed to 0.
 	_ uint8
 }
 
 // DecodeBinary implements Serializable interface.
 func (h *Header) DecodeBinary(r *io.BinReader) {
-	h.BlockBase.DecodeBinary(r)
+	h.Base.DecodeBinary(r)
 
 	padding := []byte{0}
 	r.ReadBytes(padding)
@@ -28,6 +28,6 @@ func (h *Header) DecodeBinary(r *io.BinReader) {
 
 // EncodeBinary implements Serializable interface.
 func (h *Header) EncodeBinary(w *io.BinWriter) {
-	h.BlockBase.EncodeBinary(w)
+	h.Base.EncodeBinary(w)
 	w.WriteBytes([]byte{0})
 }
diff --git a/pkg/core/block/header_test.go b/pkg/core/block/header_test.go
index 020afcbda..d7ea801f5 100644
--- a/pkg/core/block/header_test.go
+++ b/pkg/core/block/header_test.go
@@ -12,7 +12,7 @@ import (
 )
 
 func TestHeaderEncodeDecode(t *testing.T) {
-	header := Header{BlockBase: BlockBase{
+	header := Header{Base: Base{
 		Version:       0,
 		PrevHash:      hash.Sha256([]byte("prevhash")),
 		MerkleRoot:    hash.Sha256([]byte("merkleroot")),
diff --git a/pkg/core/dao_test.go b/pkg/core/dao_test.go
index cf06aa757..0bee6800f 100644
--- a/pkg/core/dao_test.go
+++ b/pkg/core/dao_test.go
@@ -262,7 +262,7 @@ func TestGetBlock_NotExists(t *testing.T) {
 func TestPutGetBlock(t *testing.T) {
 	dao := newDao(storage.NewMemoryStore())
 	b := &block.Block{
-		BlockBase: block.BlockBase{
+		Base: block.Base{
 			Script: transaction.Witness{
 				VerificationScript: []byte{byte(opcode.PUSH1)},
 				InvocationScript:   []byte{byte(opcode.NOP)},
@@ -303,7 +303,7 @@ func TestGetCurrentHeaderHeight_NoHeader(t *testing.T) {
 func TestGetCurrentHeaderHeight_Store(t *testing.T) {
 	dao := newDao(storage.NewMemoryStore())
 	b := &block.Block{
-		BlockBase: block.BlockBase{
+		Base: block.Base{
 			Script: transaction.Witness{
 				VerificationScript: []byte{byte(opcode.PUSH1)},
 				InvocationScript:   []byte{byte(opcode.NOP)},
diff --git a/pkg/core/helper_test.go b/pkg/core/helper_test.go
index 9a452ffc9..915d33ea6 100644
--- a/pkg/core/helper_test.go
+++ b/pkg/core/helper_test.go
@@ -62,7 +62,7 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
 		VerificationScript: valScript,
 	}
 	b := &block.Block{
-		BlockBase: block.BlockBase{
+		Base: block.Base{
 			Version:       0,
 			PrevHash:      newBlockPrevHash,
 			Timestamp:     uint32(time.Now().UTC().Unix()) + index,
@@ -144,7 +144,7 @@ func getBlockData(i int) (map[string]interface{}, error) {
 
 func newDumbBlock() *block.Block {
 	return &block.Block{
-		BlockBase: block.BlockBase{
+		Base: block.Base{
 			Version:       0,
 			PrevHash:      hash.Sha256([]byte("a")),
 			MerkleRoot:    hash.Sha256([]byte("b")),
diff --git a/pkg/core/util.go b/pkg/core/util.go
index 3269035de..4465a0621 100644
--- a/pkg/core/util.go
+++ b/pkg/core/util.go
@@ -25,7 +25,7 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error)
 		return nil, err
 	}
 
-	base := block.BlockBase{
+	base := block.Base{
 		Version:       0,
 		PrevHash:      util.Uint256{},
 		Timestamp:     uint32(time.Date(2016, 7, 15, 15, 8, 21, 0, time.UTC).Unix()),
@@ -50,7 +50,7 @@ func createGenesisBlock(cfg config.ProtocolConfiguration) (*block.Block, error)
 	scriptOut := hash.Hash160(rawScript)
 
 	b := &block.Block{
-		BlockBase: base,
+		Base: base,
 		Transactions: []*transaction.Transaction{
 			{
 				Type: transaction.MinerType,
diff --git a/pkg/network/blockqueue_test.go b/pkg/network/blockqueue_test.go
index 881759d33..62a43595f 100644
--- a/pkg/network/blockqueue_test.go
+++ b/pkg/network/blockqueue_test.go
@@ -15,7 +15,7 @@ func TestBlockQueue(t *testing.T) {
 	bq := newBlockQueue(0, chain, zaptest.NewLogger(t))
 	blocks := make([]*block.Block, 11)
 	for i := 1; i < 11; i++ {
-		blocks[i] = &block.Block{BlockBase: block.BlockBase{Index: uint32(i)}}
+		blocks[i] = &block.Block{Base: block.Base{Index: uint32(i)}}
 	}
 	// not the ones expected currently
 	for i := 3; i < 5; i++ {
diff --git a/pkg/network/payload/headers_test.go b/pkg/network/payload/headers_test.go
index f9fa957d0..008804eb0 100644
--- a/pkg/network/payload/headers_test.go
+++ b/pkg/network/payload/headers_test.go
@@ -30,7 +30,7 @@ func newTestHeaders(n int) *Headers {
 
 	for i := range headers.Hdrs {
 		headers.Hdrs[i] = &block.Header{
-			BlockBase: block.BlockBase{
+			Base: block.Base{
 				Index: uint32(i + 1),
 				Script: transaction.Witness{
 					InvocationScript:   []byte{0x0},
diff --git a/pkg/network/payload/merkleblock.go b/pkg/network/payload/merkleblock.go
index 9759a853c..2aa31033e 100644
--- a/pkg/network/payload/merkleblock.go
+++ b/pkg/network/payload/merkleblock.go
@@ -8,7 +8,7 @@ import (
 
 // MerkleBlock represents a merkle block packet payload.
 type MerkleBlock struct {
-	*block.BlockBase
+	*block.Base
 	TxCount int
 	Hashes  []util.Uint256
 	Flags   []byte
@@ -16,8 +16,8 @@ type MerkleBlock struct {
 
 // DecodeBinary implements Serializable interface.
 func (m *MerkleBlock) DecodeBinary(br *io.BinReader) {
-	m.BlockBase = &block.BlockBase{}
-	m.BlockBase.DecodeBinary(br)
+	m.Base = &block.Base{}
+	m.Base.DecodeBinary(br)
 
 	m.TxCount = int(br.ReadVarUint())
 	br.ReadArray(&m.Hashes)
@@ -26,8 +26,8 @@ func (m *MerkleBlock) DecodeBinary(br *io.BinReader) {
 
 // EncodeBinary implements Serializable interface.
 func (m *MerkleBlock) EncodeBinary(bw *io.BinWriter) {
-	m.BlockBase = &block.BlockBase{}
-	m.BlockBase.EncodeBinary(bw)
+	m.Base = &block.Base{}
+	m.Base.EncodeBinary(bw)
 
 	bw.WriteVarUint(uint64(m.TxCount))
 	bw.WriteArray(m.Hashes)
diff --git a/pkg/rpc/wrappers/block.go b/pkg/rpc/wrappers/block.go
index 77cf71bb0..2380f2f27 100644
--- a/pkg/rpc/wrappers/block.go
+++ b/pkg/rpc/wrappers/block.go
@@ -8,7 +8,7 @@ import (
 
 type (
 	// Block wrapper used for the representation of
-	// block.Block / block.BlockBase on the RPC Server.
+	// block.Block / block.Base on the RPC Server.
 	Block struct {
 		*block.Block
 		Confirmations uint32       `json:"confirmations"`
diff --git a/pkg/rpc/wrappers/tx_raw_output.go b/pkg/rpc/wrappers/tx_raw_output.go
index 53f3025c9..cdc2723cb 100644
--- a/pkg/rpc/wrappers/tx_raw_output.go
+++ b/pkg/rpc/wrappers/tx_raw_output.go
@@ -24,7 +24,7 @@ type TransactionOutputRaw struct {
 // NewTransactionOutputRaw returns a new ransactionOutputRaw object.
 func NewTransactionOutputRaw(tx *transaction.Transaction, header *block.Header, chain core.Blockchainer) TransactionOutputRaw {
 	// confirmations formula
-	confirmations := int(chain.BlockHeight() - header.BlockBase.Index + 1)
+	confirmations := int(chain.BlockHeight() - header.Base.Index + 1)
 	// set index position
 	for i, o := range tx.Outputs {
 		o.Position = i

From 79bceb3e40c65f49b23ee9412d5f33335ff6db61 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 15 Jan 2020 11:35:02 +0300
Subject: [PATCH 3/5] block: use require in tests

---
 pkg/core/block/block_test.go  | 17 +++++------------
 pkg/core/block/helper_test.go | 13 ++++---------
 2 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/pkg/core/block/block_test.go b/pkg/core/block/block_test.go
index 571e404d3..236ccebd8 100644
--- a/pkg/core/block/block_test.go
+++ b/pkg/core/block/block_test.go
@@ -9,20 +9,17 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/encoding/address"
 	"github.com/CityOfZion/neo-go/pkg/io"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // Test blocks are blocks from mainnet with their corresponding index.
 
 func TestDecodeBlock1(t *testing.T) {
 	data, err := getBlockData(1)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	b, err := hex.DecodeString(data["raw"].(string))
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	block := &Block{}
 	r := io.NewBinReaderFromBuf(b)
@@ -51,14 +48,10 @@ func TestTrimmedBlock(t *testing.T) {
 	block := getDecodedBlock(t, 1)
 
 	b, err := block.Trim()
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	trimmedBlock, err := NewBlockFromTrimmedBytes(b)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	assert.True(t, trimmedBlock.Trimmed)
 	assert.Equal(t, block.Version, trimmedBlock.Version)
diff --git a/pkg/core/block/helper_test.go b/pkg/core/block/helper_test.go
index 31a8f29d8..8f3821cc6 100644
--- a/pkg/core/block/helper_test.go
+++ b/pkg/core/block/helper_test.go
@@ -8,25 +8,20 @@ import (
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/io"
+	"github.com/stretchr/testify/require"
 )
 
 func getDecodedBlock(t *testing.T, i int) *Block {
 	data, err := getBlockData(i)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	b, err := hex.DecodeString(data["raw"].(string))
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	block := &Block{}
 	r := io.NewBinReaderFromBuf(b)
 	block.DecodeBinary(r)
-	if r.Err != nil {
-		t.Fatal(r.Err)
-	}
+	require.NoError(t, r.Err)
 
 	return block
 }

From fed6fba9b6249d7813b5a79d0801de74625cc336 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 15 Jan 2020 10:52:59 +0300
Subject: [PATCH 4/5] core: refactor out MemPool

---
 pkg/consensus/consensus_test.go         |  9 ++++---
 pkg/core/blockchain.go                  |  7 ++---
 pkg/core/blockchainer.go                |  5 ++--
 pkg/core/{ => mempool}/feer.go          |  2 +-
 pkg/core/{ => mempool}/mem_pool.go      |  2 +-
 pkg/core/{ => mempool}/mem_pool_test.go |  9 ++++++-
 pkg/core/mempool/prometheus.go          | 34 +++++++++++++++++++++++++
 pkg/core/prometheus.go                  | 23 -----------------
 pkg/network/helper_test.go              |  3 ++-
 pkg/network/server.go                   |  3 ++-
 10 files changed, 60 insertions(+), 37 deletions(-)
 rename pkg/core/{ => mempool}/feer.go (96%)
 rename pkg/core/{ => mempool}/mem_pool.go (99%)
 rename pkg/core/{ => mempool}/mem_pool_test.go (94%)
 create mode 100644 pkg/core/mempool/prometheus.go

diff --git a/pkg/consensus/consensus_test.go b/pkg/consensus/consensus_test.go
index 1cd450f77..08de02dd9 100644
--- a/pkg/consensus/consensus_test.go
+++ b/pkg/consensus/consensus_test.go
@@ -5,6 +5,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/core/mempool"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -20,7 +21,7 @@ func TestNewService(t *testing.T) {
 		Type: transaction.MinerType,
 		Data: &transaction.MinerTX{Nonce: 12345},
 	}
-	item := core.NewPoolItem(tx, new(feer))
+	item := mempool.NewPoolItem(tx, new(feer))
 	srv.Chain.GetMemPool().TryAdd(tx.Hash(), item)
 
 	var txx []block.Transaction
@@ -38,7 +39,7 @@ func TestService_GetVerified(t *testing.T) {
 		newMinerTx(4),
 	}
 	pool := srv.Chain.GetMemPool()
-	item := core.NewPoolItem(txs[3], new(feer))
+	item := mempool.NewPoolItem(txs[3], new(feer))
 
 	require.True(t, pool.TryAdd(txs[3].Hash(), item))
 
@@ -65,7 +66,7 @@ func TestService_GetVerified(t *testing.T) {
 
 	t.Run("more than half of the last proposal will be reused", func(t *testing.T) {
 		for _, tx := range txs[:2] {
-			item := core.NewPoolItem(tx, new(feer))
+			item := mempool.NewPoolItem(tx, new(feer))
 			require.True(t, pool.TryAdd(tx.Hash(), item))
 		}
 
@@ -114,7 +115,7 @@ func TestService_getTx(t *testing.T) {
 
 		require.Equal(t, nil, srv.getTx(h))
 
-		item := core.NewPoolItem(tx, new(feer))
+		item := mempool.NewPoolItem(tx, new(feer))
 		srv.Chain.GetMemPool().TryAdd(h, item)
 
 		got := srv.getTx(h)
diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index cd0da4930..0bf36e1dc 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core/block"
+	"github.com/CityOfZion/neo-go/pkg/core/mempool"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -77,7 +78,7 @@ type Blockchain struct {
 	stopCh      chan struct{}
 	runToExitCh chan struct{}
 
-	memPool MemPool
+	memPool mempool.MemPool
 
 	// cache for block verification keys.
 	keyCache map[util.Uint160]map[string]*keys.PublicKey
@@ -101,7 +102,7 @@ func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration, log *zap.L
 		headersOpDone: make(chan struct{}),
 		stopCh:        make(chan struct{}),
 		runToExitCh:   make(chan struct{}),
-		memPool:       NewMemPool(50000),
+		memPool:       mempool.NewMemPool(50000),
 		keyCache:      make(map[util.Uint160]map[string]*keys.PublicKey),
 		log:           log,
 	}
@@ -951,7 +952,7 @@ func (bc *Blockchain) IsLowPriority(t *transaction.Transaction) bool {
 }
 
 // GetMemPool returns the memory pool of the blockchain.
-func (bc *Blockchain) GetMemPool() MemPool {
+func (bc *Blockchain) GetMemPool() mempool.MemPool {
 	return bc.memPool
 }
 
diff --git a/pkg/core/blockchainer.go b/pkg/core/blockchainer.go
index fdeaa6072..15ade1c18 100644
--- a/pkg/core/blockchainer.go
+++ b/pkg/core/blockchainer.go
@@ -3,6 +3,7 @@ package core
 import (
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core/block"
+	"github.com/CityOfZion/neo-go/pkg/core/mempool"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -38,7 +39,7 @@ type Blockchainer interface {
 	GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
 	GetUnspentCoinState(util.Uint256) *UnspentCoinState
 	References(t *transaction.Transaction) map[transaction.Input]*transaction.Output
-	Feer // fee interface
+	mempool.Feer // fee interface
 	VerifyTx(*transaction.Transaction, *block.Block) error
-	GetMemPool() MemPool
+	GetMemPool() mempool.MemPool
 }
diff --git a/pkg/core/feer.go b/pkg/core/mempool/feer.go
similarity index 96%
rename from pkg/core/feer.go
rename to pkg/core/mempool/feer.go
index 61adbe3ca..f92c0e1d1 100644
--- a/pkg/core/feer.go
+++ b/pkg/core/mempool/feer.go
@@ -1,4 +1,4 @@
-package core
+package mempool
 
 import (
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
diff --git a/pkg/core/mem_pool.go b/pkg/core/mempool/mem_pool.go
similarity index 99%
rename from pkg/core/mem_pool.go
rename to pkg/core/mempool/mem_pool.go
index 2a629d403..404149a2a 100644
--- a/pkg/core/mem_pool.go
+++ b/pkg/core/mempool/mem_pool.go
@@ -1,4 +1,4 @@
-package core
+package mempool
 
 import (
 	"sort"
diff --git a/pkg/core/mem_pool_test.go b/pkg/core/mempool/mem_pool_test.go
similarity index 94%
rename from pkg/core/mem_pool_test.go
rename to pkg/core/mempool/mem_pool_test.go
index b75419d17..6da40043b 100644
--- a/pkg/core/mem_pool_test.go
+++ b/pkg/core/mempool/mem_pool_test.go
@@ -1,4 +1,4 @@
-package core
+package mempool
 
 import (
 	"testing"
@@ -88,3 +88,10 @@ func TestMemPoolVerify(t *testing.T) {
 	tx3.Inputs = append(tx3.Inputs, transaction.Input{PrevHash: inhash2, PrevIndex: 0})
 	require.Equal(t, false, mp.Verify(tx3))
 }
+
+func newMinerTX() *transaction.Transaction {
+	return &transaction.Transaction{
+		Type: transaction.MinerType,
+		Data: &transaction.MinerTX{},
+	}
+}
diff --git a/pkg/core/mempool/prometheus.go b/pkg/core/mempool/prometheus.go
new file mode 100644
index 000000000..3d8a6a585
--- /dev/null
+++ b/pkg/core/mempool/prometheus.go
@@ -0,0 +1,34 @@
+package mempool
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var (
+	//mempoolUnsortedTx prometheus metric.
+	mempoolUnsortedTx = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Help:      "Mempool Unsorted TXs",
+			Name:      "mempool_unsorted_tx",
+			Namespace: "neogo",
+		},
+	)
+	//mempoolUnverifiedTx prometheus metric.
+	mempoolUnverifiedTx = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Help:      "Mempool Unverified TXs",
+			Name:      "mempool_unverified_tx",
+			Namespace: "neogo",
+		},
+	)
+)
+
+func init() {
+	prometheus.MustRegister(
+		mempoolUnsortedTx,
+		mempoolUnverifiedTx,
+	)
+}
+
+func updateMempoolMetrics(unsortedTxnLen int, unverifiedTxnLen int) {
+	mempoolUnsortedTx.Set(float64(unsortedTxnLen))
+	mempoolUnverifiedTx.Set(float64(unverifiedTxnLen))
+}
diff --git a/pkg/core/prometheus.go b/pkg/core/prometheus.go
index b4bec8ca9..b81fb847d 100644
--- a/pkg/core/prometheus.go
+++ b/pkg/core/prometheus.go
@@ -30,22 +30,6 @@ var (
 			Namespace: "neogo",
 		},
 	)
-	//mempoolUnsortedTx prometheus metric.
-	mempoolUnsortedTx = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Help:      "Mempool Unsorted TXs",
-			Name:      "mempool_unsorted_tx",
-			Namespace: "neogo",
-		},
-	)
-	//mempoolUnverifiedTx prometheus metric.
-	mempoolUnverifiedTx = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Help:      "Mempool Unverified TXs",
-			Name:      "mempool_unverified_tx",
-			Namespace: "neogo",
-		},
-	)
 )
 
 func init() {
@@ -53,8 +37,6 @@ func init() {
 		blockHeight,
 		persistedHeight,
 		headerHeight,
-		mempoolUnsortedTx,
-		mempoolUnverifiedTx,
 	)
 }
 
@@ -69,8 +51,3 @@ func updateHeaderHeightMetric(hHeight int) {
 func updateBlockHeightMetric(bHeight uint32) {
 	blockHeight.Set(float64(bHeight))
 }
-
-func updateMempoolMetrics(unsortedTxnLen int, unverifiedTxnLen int) {
-	mempoolUnsortedTx.Set(float64(unsortedTxnLen))
-	mempoolUnverifiedTx.Set(float64(unverifiedTxnLen))
-}
diff --git a/pkg/network/helper_test.go b/pkg/network/helper_test.go
index e71fde016..e78b8c20f 100644
--- a/pkg/network/helper_test.go
+++ b/pkg/network/helper_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/block"
+	"github.com/CityOfZion/neo-go/pkg/core/mempool"
 	"github.com/CityOfZion/neo-go/pkg/core/state"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
@@ -116,7 +117,7 @@ func (chain testChain) GetUnspentCoinState(util.Uint256) *core.UnspentCoinState
 	panic("TODO")
 }
 
-func (chain testChain) GetMemPool() core.MemPool {
+func (chain testChain) GetMemPool() mempool.MemPool {
 	panic("TODO")
 }
 
diff --git a/pkg/network/server.go b/pkg/network/server.go
index dbda99c9f..82eed386b 100644
--- a/pkg/network/server.go
+++ b/pkg/network/server.go
@@ -13,6 +13,7 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/consensus"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/block"
+	"github.com/CityOfZion/neo-go/pkg/core/mempool"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/network/payload"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -709,7 +710,7 @@ func (s *Server) RelayTxn(t *transaction.Transaction) RelayReason {
 	// TODO: Implement Plugin.CheckPolicy?
 	//if (!Plugin.CheckPolicy(transaction))
 	// return RelayResultReason.PolicyFail;
-	if ok := s.chain.GetMemPool().TryAdd(t.Hash(), core.NewPoolItem(t, s.chain)); !ok {
+	if ok := s.chain.GetMemPool().TryAdd(t.Hash(), mempool.NewPoolItem(t, s.chain)); !ok {
 		return RelayOutOfMemory
 	}
 

From 28183b81d6c034e6c7bf9a57cc4eecebe9b4130a Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 15 Jan 2020 15:10:05 +0300
Subject: [PATCH 5/5] mempool: simplify names of exported types

With the move to a separate package, naming can be simplified:
MemPool -> Pool, PoolItem -> Item, PoolItems -> Items.
---
 pkg/core/blockchain.go       |  4 +-
 pkg/core/blockchainer.go     |  2 +-
 pkg/core/mempool/mem_pool.go | 94 ++++++++++++++++++------------------
 pkg/network/helper_test.go   |  2 +-
 4 files changed, 51 insertions(+), 51 deletions(-)

diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index 0bf36e1dc..c24de0535 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -78,7 +78,7 @@ type Blockchain struct {
 	stopCh      chan struct{}
 	runToExitCh chan struct{}
 
-	memPool mempool.MemPool
+	memPool mempool.Pool
 
 	// cache for block verification keys.
 	keyCache map[util.Uint160]map[string]*keys.PublicKey
@@ -952,7 +952,7 @@ func (bc *Blockchain) IsLowPriority(t *transaction.Transaction) bool {
 }
 
 // GetMemPool returns the memory pool of the blockchain.
-func (bc *Blockchain) GetMemPool() mempool.MemPool {
+func (bc *Blockchain) GetMemPool() mempool.Pool {
 	return bc.memPool
 }
 
diff --git a/pkg/core/blockchainer.go b/pkg/core/blockchainer.go
index 15ade1c18..34b6d70cf 100644
--- a/pkg/core/blockchainer.go
+++ b/pkg/core/blockchainer.go
@@ -41,5 +41,5 @@ type Blockchainer interface {
 	References(t *transaction.Transaction) map[transaction.Input]*transaction.Output
 	mempool.Feer // fee interface
 	VerifyTx(*transaction.Transaction, *block.Block) error
-	GetMemPool() mempool.MemPool
+	GetMemPool() mempool.Pool
 }
diff --git a/pkg/core/mempool/mem_pool.go b/pkg/core/mempool/mem_pool.go
index 404149a2a..444f2e36e 100644
--- a/pkg/core/mempool/mem_pool.go
+++ b/pkg/core/mempool/mem_pool.go
@@ -9,38 +9,38 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
-// PoolItem represents a transaction in the the Memory pool.
-type PoolItem struct {
+// Item represents a transaction in the the Memory pool.
+type Item struct {
 	txn       *transaction.Transaction
 	timeStamp time.Time
 	fee       Feer
 }
 
-// PoolItems slice of PoolItem.
-type PoolItems []*PoolItem
+// Items is a slice of Item.
+type Items []*Item
 
-// MemPool stores the unconfirms transactions.
-type MemPool struct {
+// Pool stores the unconfirms transactions.
+type Pool struct {
 	lock                        *sync.RWMutex
-	unsortedTxn                 map[util.Uint256]*PoolItem
-	unverifiedTxn               map[util.Uint256]*PoolItem
-	sortedHighPrioTxn           PoolItems
-	sortedLowPrioTxn            PoolItems
-	unverifiedSortedHighPrioTxn PoolItems
-	unverifiedSortedLowPrioTxn  PoolItems
+	unsortedTxn                 map[util.Uint256]*Item
+	unverifiedTxn               map[util.Uint256]*Item
+	sortedHighPrioTxn           Items
+	sortedLowPrioTxn            Items
+	unverifiedSortedHighPrioTxn Items
+	unverifiedSortedLowPrioTxn  Items
 
 	capacity int
 }
 
-func (p PoolItems) Len() int           { return len(p) }
-func (p PoolItems) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
-func (p PoolItems) Less(i, j int) bool { return p[i].CompareTo(p[j]) < 0 }
+func (p Items) Len() int           { return len(p) }
+func (p Items) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p Items) Less(i, j int) bool { return p[i].CompareTo(p[j]) < 0 }
 
-// CompareTo returns the difference between two PoolItems.
+// CompareTo returns the difference between two Items.
 // difference < 0 implies p < otherP.
 // difference = 0 implies p = otherP.
 // difference > 0 implies p > otherP.
-func (p PoolItem) CompareTo(otherP *PoolItem) int {
+func (p Item) CompareTo(otherP *Item) int {
 	if otherP == nil {
 		return 1
 	}
@@ -77,15 +77,15 @@ func (p PoolItem) CompareTo(otherP *PoolItem) int {
 }
 
 // Count returns the total number of uncofirm transactions.
-func (mp MemPool) Count() int {
+func (mp Pool) Count() int {
 	mp.lock.RLock()
 	defer mp.lock.RUnlock()
 
 	return len(mp.unsortedTxn) + len(mp.unverifiedTxn)
 }
 
-// ContainsKey checks if a transactions hash is in the MemPool.
-func (mp MemPool) ContainsKey(hash util.Uint256) bool {
+// ContainsKey checks if a transactions hash is in the Pool.
+func (mp Pool) ContainsKey(hash util.Uint256) bool {
 	mp.lock.RLock()
 	defer mp.lock.RUnlock()
 
@@ -100,9 +100,9 @@ func (mp MemPool) ContainsKey(hash util.Uint256) bool {
 	return false
 }
 
-// TryAdd try to add the PoolItem to the MemPool.
-func (mp MemPool) TryAdd(hash util.Uint256, pItem *PoolItem) bool {
-	var pool PoolItems
+// TryAdd try to add the Item to the Pool.
+func (mp Pool) TryAdd(hash util.Uint256, pItem *Item) bool {
+	var pool Items
 
 	mp.lock.Lock()
 	if _, ok := mp.unsortedTxn[hash]; ok {
@@ -135,13 +135,13 @@ func (mp MemPool) TryAdd(hash util.Uint256, pItem *PoolItem) bool {
 
 // Remove removes an item from the mempool, if it exists there (and does
 // nothing if it doesn't).
-func (mp *MemPool) Remove(hash util.Uint256) {
+func (mp *Pool) Remove(hash util.Uint256) {
 	var mapAndPools = []struct {
-		unsortedMap map[util.Uint256]*PoolItem
-		sortedPools []*PoolItems
+		unsortedMap map[util.Uint256]*Item
+		sortedPools []*Items
 	}{
-		{unsortedMap: mp.unsortedTxn, sortedPools: []*PoolItems{&mp.sortedHighPrioTxn, &mp.sortedLowPrioTxn}},
-		{unsortedMap: mp.unverifiedTxn, sortedPools: []*PoolItems{&mp.unverifiedSortedHighPrioTxn, &mp.unverifiedSortedLowPrioTxn}},
+		{unsortedMap: mp.unsortedTxn, sortedPools: []*Items{&mp.sortedHighPrioTxn, &mp.sortedLowPrioTxn}},
+		{unsortedMap: mp.unverifiedTxn, sortedPools: []*Items{&mp.unverifiedSortedHighPrioTxn, &mp.unverifiedSortedLowPrioTxn}},
 	}
 	mp.lock.Lock()
 	for _, mapAndPool := range mapAndPools {
@@ -149,7 +149,7 @@ func (mp *MemPool) Remove(hash util.Uint256) {
 			delete(mapAndPool.unsortedMap, hash)
 			for _, pool := range mapAndPool.sortedPools {
 				var num int
-				var item *PoolItem
+				var item *Item
 				for num, item = range *pool {
 					if hash.Equals(item.txn.Hash()) {
 						break
@@ -168,8 +168,8 @@ func (mp *MemPool) Remove(hash util.Uint256) {
 }
 
 // RemoveOverCapacity removes transactions with lowest fees until the total number of transactions
-// in the MemPool is within the capacity of the MemPool.
-func (mp *MemPool) RemoveOverCapacity() {
+// in the Pool is within the capacity of the Pool.
+func (mp *Pool) RemoveOverCapacity() {
 	for mp.Count()-mp.capacity > 0 {
 		mp.lock.Lock()
 		if minItem, argPosition := getLowestFeeTransaction(mp.sortedLowPrioTxn, mp.unverifiedSortedLowPrioTxn); minItem != nil {
@@ -205,27 +205,27 @@ func (mp *MemPool) RemoveOverCapacity() {
 
 }
 
-// NewPoolItem returns a new PoolItem.
-func NewPoolItem(t *transaction.Transaction, fee Feer) *PoolItem {
-	return &PoolItem{
+// NewPoolItem returns a new Item.
+func NewPoolItem(t *transaction.Transaction, fee Feer) *Item {
+	return &Item{
 		txn:       t,
 		timeStamp: time.Now().UTC(),
 		fee:       fee,
 	}
 }
 
-// NewMemPool returns a new MemPool struct.
-func NewMemPool(capacity int) MemPool {
-	return MemPool{
+// NewMemPool returns a new Pool struct.
+func NewMemPool(capacity int) Pool {
+	return Pool{
 		lock:          new(sync.RWMutex),
-		unsortedTxn:   make(map[util.Uint256]*PoolItem),
-		unverifiedTxn: make(map[util.Uint256]*PoolItem),
+		unsortedTxn:   make(map[util.Uint256]*Item),
+		unverifiedTxn: make(map[util.Uint256]*Item),
 		capacity:      capacity,
 	}
 }
 
 // TryGetValue returns a transaction if it exists in the memory pool.
-func (mp MemPool) TryGetValue(hash util.Uint256) (*transaction.Transaction, bool) {
+func (mp Pool) TryGetValue(hash util.Uint256) (*transaction.Transaction, bool) {
 	mp.lock.RLock()
 	defer mp.lock.RUnlock()
 	if pItem, ok := mp.unsortedTxn[hash]; ok {
@@ -239,13 +239,13 @@ func (mp MemPool) TryGetValue(hash util.Uint256) (*transaction.Transaction, bool
 	return nil, false
 }
 
-// getLowestFeeTransaction returns the PoolItem with the lowest fee amongst the "verifiedTxnSorted"
-// and "unverifiedTxnSorted" PoolItems along with a integer. The integer can assume two values, 1 and 2 which indicate
-// that the PoolItem with the lowest fee was found in "verifiedTxnSorted" respectively in "unverifiedTxnSorted".
+// getLowestFeeTransaction returns the Item with the lowest fee amongst the "verifiedTxnSorted"
+// and "unverifiedTxnSorted" Items along with a integer. The integer can assume two values, 1 and 2 which indicate
+// that the Item with the lowest fee was found in "verifiedTxnSorted" respectively in "unverifiedTxnSorted".
 // "verifiedTxnSorted" and "unverifiedTxnSorted" are sorted slice order by transaction fee ascending. This means that
 // the transaction with lowest fee start at index 0.
 // Reference: GetLowestFeeTransaction method in C# (https://github.com/neo-project/neo/blob/master/neo/Ledger/MemoryPool.cs)
-func getLowestFeeTransaction(verifiedTxnSorted PoolItems, unverifiedTxnSorted PoolItems) (*PoolItem, int) {
+func getLowestFeeTransaction(verifiedTxnSorted Items, unverifiedTxnSorted Items) (*Item, int) {
 	minItem := min(unverifiedTxnSorted)
 	verifiedMin := min(verifiedTxnSorted)
 	if verifiedMin == nil || (minItem != nil && verifiedMin.CompareTo(minItem) >= 0) {
@@ -259,7 +259,7 @@ func getLowestFeeTransaction(verifiedTxnSorted PoolItems, unverifiedTxnSorted Po
 
 // min returns the minimum item in a ascending sorted slice of pool items.
 // The function can't be applied to unsorted slice!
-func min(sortedPool PoolItems) *PoolItem {
+func min(sortedPool Items) *Item {
 	if len(sortedPool) == 0 {
 		return nil
 	}
@@ -268,7 +268,7 @@ func min(sortedPool PoolItems) *PoolItem {
 
 // GetVerifiedTransactions returns a slice of Input from all the transactions in the memory pool
 // whose hash is not included in excludedHashes.
-func (mp *MemPool) GetVerifiedTransactions() []*transaction.Transaction {
+func (mp *Pool) GetVerifiedTransactions() []*transaction.Transaction {
 	mp.lock.RLock()
 	defer mp.lock.RUnlock()
 
@@ -286,7 +286,7 @@ func (mp *MemPool) GetVerifiedTransactions() []*transaction.Transaction {
 // Verify verifies if the inputs of a transaction tx are already used in any other transaction in the memory pool.
 // If yes, the transaction tx is not a valid transaction and the function return false.
 // If no, the transaction tx is a valid transaction and the function return true.
-func (mp MemPool) Verify(tx *transaction.Transaction) bool {
+func (mp Pool) Verify(tx *transaction.Transaction) bool {
 	mp.lock.RLock()
 	defer mp.lock.RUnlock()
 	for _, item := range mp.unsortedTxn {
diff --git a/pkg/network/helper_test.go b/pkg/network/helper_test.go
index e78b8c20f..ddfec8e67 100644
--- a/pkg/network/helper_test.go
+++ b/pkg/network/helper_test.go
@@ -117,7 +117,7 @@ func (chain testChain) GetUnspentCoinState(util.Uint256) *core.UnspentCoinState
 	panic("TODO")
 }
 
-func (chain testChain) GetMemPool() mempool.MemPool {
+func (chain testChain) GetMemPool() mempool.Pool {
 	panic("TODO")
 }