Persist blockchain with leveldb on disk (#48)

* Created test_data folder with block json files for testing + create separate file for block base.

* Fixed bug in WriteVarUint + Trim logic + unit tests

* Refactored store and add more tests for it.

* restore headerList from chain file

* Fix tx decode bug + lots of housekeeping.

* Implemented Node restore state from chain file.

* Created standalone package for storage. Added couple more methods to Batch and Store interfaces.

* Block persisting + tests

* bumped version -> 0.31.0

pkg/core/blockchain_test.go

@@ -3,22 +3,13 @@ package core
 import (
 	"testing"
 
+	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestNewBlockchain(t *testing.T) {
-	startHash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
-	bc := NewBlockchain(nil, startHash)
-
-	assert.Equal(t, uint32(0), bc.BlockHeight())
-	assert.Equal(t, uint32(0), bc.HeaderHeight())
-	assert.Equal(t, uint32(1), bc.storedHeaderCount)
-	assert.Equal(t, startHash, bc.startHash)
-}
-
 func TestAddHeaders(t *testing.T) {
-	bc := newTestBC()
+	bc := newTestChain(t)
 	h1 := newBlock(1).Header()
 	h2 := newBlock(2).Header()
 	h3 := newBlock(3).Header()
@@ -45,7 +36,7 @@ func TestAddHeaders(t *testing.T) {
 }
 
 func TestAddBlock(t *testing.T) {
-	bc := newTestBC()
+	bc := newTestChain(t)
 	blocks := []*Block{
 		newBlock(1),
 		newBlock(2),
@@ -73,8 +64,69 @@ func TestAddBlock(t *testing.T) {
 	assert.Equal(t, 0, bc.blockCache.Len())
 }
 
-func newTestBC() *Blockchain {
-	startHash, _ := util.Uint256DecodeString("a")
-	bc := NewBlockchain(NewMemoryStore(), startHash)
-	return bc
+func TestGetHeader(t *testing.T) {
+	bc := newTestChain(t)
+	block := newBlock(1)
+	err := bc.AddBlock(block)
+	assert.Nil(t, err)
+
+	hash := block.Hash()
+	header, err := bc.getHeader(hash)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, block.Header(), header)
+
+	block = newBlock(2)
+	hash = block.Hash()
+	_, err = bc.getHeader(block.Hash())
+	assert.NotNil(t, err)
+}
+
+func TestGetBlock(t *testing.T) {
+	bc := newTestChain(t)
+	blocks := makeBlocks(100)
+
+	for i := 0; i < len(blocks); i++ {
+		if err := bc.AddBlock(blocks[i]); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	for i := 0; i < len(blocks); i++ {
+		block, err := bc.GetBlock(blocks[i].Hash())
+		if err != nil {
+			t.Fatal(err)
+		}
+		assert.Equal(t, blocks[i].Index, block.Index)
+		assert.Equal(t, blocks[i].Hash(), block.Hash())
+	}
+}
+
+func TestHasBlock(t *testing.T) {
+	bc := newTestChain(t)
+	blocks := makeBlocks(50)
+
+	for i := 0; i < len(blocks); i++ {
+		if err := bc.AddBlock(blocks[i]); err != nil {
+			t.Fatal(err)
+		}
+	}
+	assert.Nil(t, bc.persist())
+
+	for i := 0; i < len(blocks); i++ {
+		assert.True(t, bc.HasBlock(blocks[i].Hash()))
+	}
+
+	newBlock := newBlock(51)
+	assert.False(t, bc.HasBlock(newBlock.Hash()))
+}
+
+func newTestChain(t *testing.T) *Blockchain {
+	startHash, _ := util.Uint256DecodeString("a")
+	chain, err := NewBlockchain(storage.NewMemoryStore(), startHash)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return chain
 }