tests: add helper functions for block tests

tests/blocktest.go

+package tests
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"math/big"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethutil"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/state"
+)
+
+// Block Test JSON Format
+
+type btJSON struct {
+	Blocks             []btBlock
+	GenesisBlockHeader btHeader
+	Pre                map[string]btAccount
+}
+
+type btAccount struct {
+	Balance string
+	Code    string
+	Nonce   string
+	Storage map[string]string
+}
+
+type btHeader struct {
+	Bloom            string
+	Coinbase         string
+	MixHash          string
+	Nonce            string
+	Number           string
+	ParentHash       string
+	ReceiptTrie      string
+	SeedHash         string
+	StateRoot        string
+	TransactionsTrie string
+	UncleHash        string
+
+	ExtraData  string
+	Difficulty string
+	GasLimit   string
+	GasUsed    string
+	Timestamp  string
+}
+
+type btTransaction struct {
+	Data     string
+	GasLimit string
+	GasPrice string
+	Nonce    string
+	R        string
+	S        string
+	To       string
+	V        string
+	Value    string
+}
+
+type btBlock struct {
+	BlockHeader  *btHeader
+	Rlp          string
+	Transactions []btTransaction
+	UncleHeaders []string
+}
+
+type BlockTest struct {
+	Genesis *types.Block
+	Blocks  []*types.Block
+
+	preAccounts map[string]btAccount
+}
+
+// LoadBlockTests loads a block test JSON file.
+func LoadBlockTests(file string) (map[string]*BlockTest, error) {
+	bt := make(map[string]*btJSON)
+	if err := loadJSON(file, &bt); err != nil {
+		return nil, err
+	}
+	out := make(map[string]*BlockTest)
+	for name, in := range bt {
+		var err error
+		if out[name], err = convertTest(in); err != nil {
+			return nil, fmt.Errorf("bad test %q: %v", err)
+		}
+	}
+	return out, nil
+}
+
+// InsertPreState populates the given database with the genesis
+// accounts defined by the test.
+func (t *BlockTest) InsertPreState(db ethutil.Database) error {
+	statedb := state.New(nil, db)
+	for addrString, acct := range t.preAccounts {
+		// XXX: is is worth it checking for errors here?
+		addr, _ := hex.DecodeString(addrString)
+		code, _ := hex.DecodeString(strings.TrimPrefix(acct.Code, "0x"))
+		balance, _ := new(big.Int).SetString(acct.Balance, 0)
+		nonce, _ := strconv.ParseUint(acct.Nonce, 16, 64)
+
+		obj := statedb.NewStateObject(addr)
+		obj.SetCode(code)
+		obj.SetBalance(balance)
+		obj.SetNonce(nonce)
+		// for k, v := range acct.Storage {
+		// 	obj.SetState(k, v)
+		// }
+	}
+	// sync objects to trie
+	statedb.Update(nil)
+	// sync trie to disk
+	statedb.Sync()
+
+	if !bytes.Equal(t.Genesis.Root(), statedb.Root()) {
+		return errors.New("computed state root does not match genesis block")
+	}
+	return nil
+}
+
+func convertTest(in *btJSON) (out *BlockTest, err error) {
+	// the conversion handles errors by catching panics.
+	// you might consider this ugly, but the alternative (passing errors)
+	// would be much harder to read.
+	defer func() {
+		if recovered := recover(); recovered != nil {
+			buf := make([]byte, 64<<10)
+			buf = buf[:runtime.Stack(buf, false)]
+			err = fmt.Errorf("%v\n%s", recovered, buf)
+		}
+	}()
+	out = &BlockTest{preAccounts: in.Pre}
+	out.Genesis = mustConvertGenesis(in.GenesisBlockHeader)
+	out.Blocks = mustConvertBlocks(in.Blocks)
+	return out, err
+}
+
+func mustConvertGenesis(testGenesis btHeader) *types.Block {
+	hdr := mustConvertHeader(testGenesis)
+	hdr.Number = big.NewInt(0)
+	b := types.NewBlockWithHeader(hdr)
+	b.Td = new(big.Int)
+	b.Reward = new(big.Int)
+	return b
+}
+
+func mustConvertHeader(in btHeader) *types.Header {
+	// hex decode these fields
+	return &types.Header{
+		SeedHash:    mustConvertBytes(in.SeedHash),
+		MixDigest:   mustConvertBytes(in.MixHash),
+		Bloom:       mustConvertBytes(in.Bloom),
+		ReceiptHash: mustConvertBytes(in.ReceiptTrie),
+		TxHash:      mustConvertBytes(in.TransactionsTrie),
+		Root:        mustConvertBytes(in.StateRoot),
+		Coinbase:    mustConvertBytes(in.Coinbase),
+		UncleHash:   mustConvertBytes(in.UncleHash),
+		ParentHash:  mustConvertBytes(in.ParentHash),
+		Nonce:       mustConvertBytes(in.Nonce),
+		Extra:       string(mustConvertBytes(in.ExtraData)),
+		GasUsed:     mustConvertBigInt10(in.GasUsed),
+		GasLimit:    mustConvertBigInt10(in.GasLimit),
+		Difficulty:  mustConvertBigInt10(in.Difficulty),
+		Time:        mustConvertUint(in.Timestamp),
+	}
+}
+
+func mustConvertBlocks(testBlocks []btBlock) []*types.Block {
+	var out []*types.Block
+	for i, inb := range testBlocks {
+		var b types.Block
+		r := bytes.NewReader(mustConvertBytes(inb.Rlp))
+		if err := rlp.Decode(r, &b); err != nil {
+			panic(fmt.Errorf("invalid block %d: %q", i, inb.Rlp))
+		}
+		out = append(out, &b)
+	}
+	return out
+}
+
+func mustConvertBytes(in string) []byte {
+	out, err := hex.DecodeString(strings.TrimPrefix(in, "0x"))
+	if err != nil {
+		panic(fmt.Errorf("invalid hex: %q", in))
+	}
+	return out
+}
+
+func mustConvertBigInt10(in string) *big.Int {
+	out, ok := new(big.Int).SetString(in, 10)
+	if !ok {
+		panic(fmt.Errorf("invalid integer: %q", in))
+	}
+	return out
+}
+
+func mustConvertUint(in string) uint64 {
+	out, err := strconv.ParseUint(in, 0, 64)
+	if err != nil {
+		panic(fmt.Errorf("invalid integer: %q", in))
+	}
+	return out
+}
+
+// loadJSON reads the given file and unmarshals its content.
+func loadJSON(file string, val interface{}) error {
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(content, val); err != nil {
+		if syntaxerr, ok := err.(*json.SyntaxError); ok {
+			line := findLine(content, syntaxerr.Offset)
+			return fmt.Errorf("JSON syntax error at %v:%v: %v", file, line, err)
+		}
+		return fmt.Errorf("JSON unmarshal error in %v: %v", file, err)
+	}
+	return nil
+}
+
+// findLine returns the line number for the given offset into data.
+func findLine(data []byte, offset int64) (line int) {
+	line = 1
+	for i, r := range string(data) {
+		if int64(i) >= offset {
+			return
+		}
+		if r == '\n' {
+			line++
+		}
+	}
+	return
+}