core: get rid of global variables in tests

It can lead to unnecessary race conditions and is just
a bad practice.

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"
@@ -14,9 +15,10 @@ import (
 
 func TestAddHeaders(t *testing.T) {
 	bc := newTestChain(t)
-	h1 := newBlock(1).Header()
-	h2 := newBlock(2).Header()
-	h3 := newBlock(3).Header()
+	lastBlock := bc.topBlock.Load().(*block.Block)
+	h1 := newBlock(bc.config, 1, lastBlock.Hash()).Header()
+	h2 := newBlock(bc.config, 2, h1.Hash()).Header()
+	h3 := newBlock(bc.config, 3, h2.Hash()).Header()
 
 	if err := bc.AddHeaders(h1, h2, h3); err != nil {
 		t.Fatal(err)
@@ -83,7 +85,7 @@ func TestScriptFromWitness(t *testing.T) {
 
 func TestGetHeader(t *testing.T) {
 	bc := newTestChain(t)
-	block := newBlock(1, newMinerTX())
+	block := bc.newBlock(newMinerTX())
 	err := bc.AddBlock(block)
 	assert.Nil(t, err)
 
@@ -94,7 +96,7 @@ func TestGetHeader(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, block.Header(), header)
 
-		b2 := newBlock(2)
+		b2 := bc.newBlock()
 		_, err = bc.GetHeader(b2.Hash())
 		assert.Error(t, err)
 		assert.NoError(t, bc.persist())
@@ -130,7 +132,7 @@ func TestHasBlock(t *testing.T) {
 		for i := 0; i < len(blocks); i++ {
 			assert.True(t, bc.HasBlock(blocks[i].Hash()))
 		}
-		newBlock := newBlock(51)
+		newBlock := bc.newBlock()
 		assert.False(t, bc.HasBlock(newBlock.Hash()))
 		assert.NoError(t, bc.persist())
 	}

pkg/core/helper_test.go

@@ -24,9 +24,6 @@ import (
 	"go.uber.org/zap/zaptest"
 )
 
-var newBlockPrevHash util.Uint256
-var unitTestNetCfg config.Config
-
 var privNetKeys = []string{
 	"KxyjQ8eUa4FHt3Gvioyt1Wz29cTUrE4eTqX3yFSk1YFCsPL8uNsY",
 	"KzfPUYDC9n2yf4fK5ro4C8KMcdeXtFuEnStycbZgX3GomiUsvX6W",
@@ -37,8 +34,7 @@ var privNetKeys = []string{
 // newTestChain should be called before newBlock invocation to properly setup
 // global state.
 func newTestChain(t *testing.T) *Blockchain {
-	var err error
-	unitTestNetCfg, err = config.Load("../../config", config.ModeUnitTestNet)
+	unitTestNetCfg, err := config.Load("../../config", config.ModeUnitTestNet)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -47,14 +43,16 @@ func newTestChain(t *testing.T) *Blockchain {
 		t.Fatal(err)
 	}
 	go chain.Run()
-	zeroHash, err := chain.GetHeader(chain.GetHeaderHash(0))
-	require.Nil(t, err)
-	newBlockPrevHash = zeroHash.Hash()
 	return chain
 }
 
-func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
-	validators, _ := getValidators(unitTestNetCfg.ProtocolConfiguration)
+func (bc *Blockchain) newBlock(txs ...*transaction.Transaction) *block.Block {
+	lastBlock := bc.topBlock.Load().(*block.Block)
+	return newBlock(bc.config, lastBlock.Index+1, lastBlock.Hash(), txs...)
+}
+
+func newBlock(cfg config.ProtocolConfiguration, index uint32, prev util.Uint256, txs ...*transaction.Transaction) *block.Block {
+	validators, _ := getValidators(cfg)
 	vlen := len(validators)
 	valScript, _ := smartcontract.CreateMultiSigRedeemScript(
 		vlen-(vlen-1)/3,
@@ -66,7 +64,7 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
 	b := &block.Block{
 		Base: block.Base{
 			Version:       0,
-			PrevHash:      newBlockPrevHash,
+			PrevHash:      prev,
 			Timestamp:     uint32(time.Now().UTC().Unix()) + index,
 			Index:         index,
 			ConsensusData: 1111,
@@ -76,7 +74,6 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
 		Transactions: txs,
 	}
 	_ = b.RebuildMerkleRoot()
-	newBlockPrevHash = b.Hash()
 
 	invScript := make([]byte, 0)
 	for _, wif := range privNetKeys {
@@ -98,11 +95,13 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *block.Block {
 
 func (bc *Blockchain) genBlocks(n int) ([]*block.Block, error) {
 	blocks := make([]*block.Block, n)
+	lastHash := bc.topBlock.Load().(*block.Block).Hash()
 	for i := 0; i < n; i++ {
-		blocks[i] = newBlock(uint32(i)+1, newMinerTX())
+		blocks[i] = newBlock(bc.config, uint32(i)+1, lastHash, newMinerTX())
 		if err := bc.AddBlock(blocks[i]); err != nil {
 			return blocks, err
 		}
+		lastHash = blocks[i].Hash()
 	}
 	return blocks, nil
 }
@@ -207,7 +206,7 @@ func _(t *testing.T) {
 
 	tx2 := transaction.NewInvocationTX(txScript, util.Fixed8FromFloat(100))
 
-	block := newBlock(uint32(n+1), tx1, tx2)
+	block := bc.newBlock(tx1, tx2)
 	if err := bc.AddBlock(block); err != nil {
 		t.Fatal(err)
 	}
@@ -221,7 +220,7 @@ func _(t *testing.T) {
 	emit.AppCall(script.BinWriter, hash.Hash160(avm), false)
 
 	tx3 := transaction.NewInvocationTX(script.Bytes(), util.Fixed8FromFloat(100))
-	b := newBlock(uint32(n+2), newMinerTX(), tx3)
+	b := bc.newBlock(newMinerTX(), tx3)
 	require.NoError(t, bc.AddBlock(b))
 
 	outStream, err := os.Create("../rpc/testdata/testblocks.acc")