Golang wire.NewTxIn函數代碼示例

// newLightningChannel...
func newLightningChannel(wallet *LightningWallet, events chainntnfs.ChainNotifier,
	chanDB *channeldb.DB, state *channeldb.OpenChannel) (*LightningChannel, error) {

	lc := &LightningChannel{
		lnwallet:           wallet,
		channelEvents:      events,
		channelState:       state,
		channelDB:          chanDB,
		updateTotem:        make(chan struct{}, 1),
		pendingPayments:    make(map[PaymentHash]*PaymentDescriptor),
		unfufilledPayments: make(map[PaymentHash]*PaymentRequest),
	}

	// TODO(roasbeef): do a NotifySpent for the funding input, and
	// NotifyReceived for all commitment outputs.

	// Populate the totem.
	lc.updateTotem <- struct{}{}

	fundingTxId := state.FundingTx.TxSha()
	fundingPkScript, err := scriptHashPkScript(state.FundingRedeemScript)
	if err != nil {
		return nil, err
	}
	_, multiSigIndex := findScriptOutputIndex(state.FundingTx, fundingPkScript)
	lc.fundingTxIn = wire.NewTxIn(wire.NewOutPoint(&fundingTxId, multiSigIndex), nil)
	lc.fundingP2SH = fundingPkScript

	return lc, nil
}

// createSpendTx generates a basic spending transaction given the passed
// signature and public key scripts.
func createSpendingTx(sigScript, pkScript []byte) *wire.MsgTx {
	coinbaseTx := wire.NewMsgTx(wire.TxVersion)

	outPoint := wire.NewOutPoint(&chainhash.Hash{}, ^uint32(0))
	txIn := wire.NewTxIn(outPoint, []byte{OP_0, OP_0})
	txOut := wire.NewTxOut(0, pkScript)
	coinbaseTx.AddTxIn(txIn)
	coinbaseTx.AddTxOut(txOut)

	spendingTx := wire.NewMsgTx(wire.TxVersion)
	coinbaseTxHash := coinbaseTx.TxHash()
	outPoint = wire.NewOutPoint(&coinbaseTxHash, 0)
	txIn = wire.NewTxIn(outPoint, sigScript)
	txOut = wire.NewTxOut(0, nil)

	spendingTx.AddTxIn(txIn)
	spendingTx.AddTxOut(txOut)

	return spendingTx
}

// createSpendTx generates a basic spending transaction given the passed
// signature and public key scripts.
func createSpendingTx(sigScript, pkScript []byte) *wire.MsgTx {
	coinbaseTx := wire.NewMsgTx()

	outPoint := wire.NewOutPoint(&wire.ShaHash{}, ^uint32(0))
	txIn := wire.NewTxIn(outPoint, []byte{OP_0, OP_0})
	txOut := wire.NewTxOut(0, pkScript)
	coinbaseTx.AddTxIn(txIn)
	coinbaseTx.AddTxOut(txOut)

	spendingTx := wire.NewMsgTx()
	coinbaseTxSha := coinbaseTx.TxSha()
	outPoint = wire.NewOutPoint(&coinbaseTxSha, 0)
	txIn = wire.NewTxIn(outPoint, sigScript)
	txOut = wire.NewTxOut(0, nil)

	spendingTx.AddTxIn(txIn)
	spendingTx.AddTxOut(txOut)

	return spendingTx
}

// toMsgTx generates a btcwire.MsgTx with this tx's inputs and outputs.
func (tx *withdrawalTx) toMsgTx() *wire.MsgTx {
	msgtx := wire.NewMsgTx(wire.TxVersion)
	for _, o := range tx.outputs {
		msgtx.AddTxOut(wire.NewTxOut(int64(o.amount), o.pkScript()))
	}

	if tx.hasChange() {
		msgtx.AddTxOut(tx.changeOutput)
	}

	for _, i := range tx.inputs {
		msgtx.AddTxIn(wire.NewTxIn(&i.OutPoint, []byte{}))
	}
	return msgtx
}

func makeInputSource(unspents []*wire.TxOut) InputSource {
	// Return outputs in order.
	currentTotal := btcutil.Amount(0)
	currentInputs := make([]*wire.TxIn, 0, len(unspents))
	f := func(target btcutil.Amount) (btcutil.Amount, []*wire.TxIn, [][]byte, error) {
		for currentTotal < target && len(unspents) != 0 {
			u := unspents[0]
			unspents = unspents[1:]
			nextInput := wire.NewTxIn(&wire.OutPoint{}, nil)
			currentTotal += btcutil.Amount(u.Value)
			currentInputs = append(currentInputs, nextInput)
		}
		return currentTotal, currentInputs, make([][]byte, len(currentInputs)), nil
	}
	return InputSource(f)
}

// makeInputSource creates an InputSource that creates inputs for every unspent
// output with non-zero output values.  The target amount is ignored since every
// output is consumed.  The InputSource does not return any previous output
// scripts as they are not needed for creating the unsinged transaction and are
// looked up again by the wallet during the call to signrawtransaction.
func makeInputSource(outputs []btcjson.ListUnspentResult) txauthor.InputSource {
	var (
		totalInputValue btcutil.Amount
		inputs          = make([]*wire.TxIn, 0, len(outputs))
		sourceErr       error
	)
	for _, output := range outputs {
		outputAmount, err := btcutil.NewAmount(output.Amount)
		if err != nil {
			sourceErr = fmt.Errorf(
				"invalid amount `%v` in listunspent result",
				output.Amount)
			break
		}
		if outputAmount == 0 {
			continue
		}
		if !saneOutputValue(outputAmount) {
			sourceErr = fmt.Errorf(
				"impossible output amount `%v` in listunspent result",
				outputAmount)
			break
		}
		totalInputValue += outputAmount

		previousOutPoint, err := parseOutPoint(&output)
		if err != nil {
			sourceErr = fmt.Errorf(
				"invalid data in listunspent result: %v",
				err)
			break
		}

		inputs = append(inputs, wire.NewTxIn(&previousOutPoint, nil))
	}

	if sourceErr == nil && totalInputValue == 0 {
		sourceErr = noInputValue{}
	}

	return func(btcutil.Amount) (btcutil.Amount, []*wire.TxIn, [][]byte, error) {
		return totalInputValue, inputs, nil, sourceErr
	}
}

// newBobNode generates a test "ln node" to interact with Alice (us). For the
// funding transaction, bob has a single output totaling 7BTC. For our basic
// test, he'll fund the channel with 5BTC, leaving 2BTC to the change output.
// TODO(roasbeef): proper handling of change etc.
func newBobNode() (*bobNode, error) {
	// First, parse Bob's priv key in order to obtain a key he'll use for the
	// multi-sig funding transaction.
	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), bobsPrivKey)

	// Next, generate an output redeemable by bob.
	bobAddr, err := btcutil.NewAddressPubKey(privKey.PubKey().SerializeCompressed(),
		ActiveNetParams)
	if err != nil {
		return nil, err
	}
	bobAddrScript, err := txscript.PayToAddrScript(bobAddr.AddressPubKeyHash())
	if err != nil {
		return nil, err
	}
	prevOut := wire.NewOutPoint(&wire.ShaHash{}, ^uint32(0))
	// TODO(roasbeef): When the chain rpc is hooked in, assert bob's output
	// actually exists and it unspent in the chain.
	bobTxIn := wire.NewTxIn(prevOut, nil)

	// Using bobs priv key above, create a change address he can spend.
	bobChangeOutput := wire.NewTxOut(2*1e8, bobAddrScript)

	// Bob's initial revocation hash is just his private key with the first
	// byte changed...
	var revocation [20]byte
	copy(revocation[:], bobsPrivKey)
	revocation[0] = 0xff

	// His ID is just as creative...
	var id [wire.HashSize]byte
	id[0] = 0xff

	return &bobNode{
		id:               id,
		privKey:          privKey,
		channelKey:       pubKey,
		deliveryAddress:  bobAddr,
		revocation:       revocation,
		delay:            5,
		availableOutputs: []*wire.TxIn{bobTxIn},
		changeOutputs:    []*wire.TxOut{bobChangeOutput},
	}, nil
}

// TestCheckSerializedHeight tests the checkSerializedHeight function with
// various serialized heights and also does negative tests to ensure errors
// and handled properly.
func TestCheckSerializedHeight(t *testing.T) {
	// Create an empty coinbase template to be used in the tests below.
	coinbaseOutpoint := wire.NewOutPoint(&chainhash.Hash{}, math.MaxUint32)
	coinbaseTx := wire.NewMsgTx(1)
	coinbaseTx.AddTxIn(wire.NewTxIn(coinbaseOutpoint, nil))

	// Expected rule errors.
	missingHeightError := blockchain.RuleError{
		ErrorCode: blockchain.ErrMissingCoinbaseHeight,
	}
	badHeightError := blockchain.RuleError{
		ErrorCode: blockchain.ErrBadCoinbaseHeight,
	}

	tests := []struct {
		sigScript  []byte // Serialized data
		wantHeight int32  // Expected height
		err        error  // Expected error type
	}{
		// No serialized height length.
		{[]byte{}, 0, missingHeightError},
		// Serialized height length with no height bytes.
		{[]byte{0x02}, 0, missingHeightError},
		// Serialized height length with too few height bytes.
		{[]byte{0x02, 0x4a}, 0, missingHeightError},
		// Serialized height that needs 2 bytes to encode.
		{[]byte{0x02, 0x4a, 0x52}, 21066, nil},
		// Serialized height that needs 2 bytes to encode, but backwards
		// endianness.
		{[]byte{0x02, 0x4a, 0x52}, 19026, badHeightError},
		// Serialized height that needs 3 bytes to encode.
		{[]byte{0x03, 0x40, 0x0d, 0x03}, 200000, nil},
		// Serialized height that needs 3 bytes to encode, but backwards
		// endianness.
		{[]byte{0x03, 0x40, 0x0d, 0x03}, 1074594560, badHeightError},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		msgTx := coinbaseTx.Copy()
		msgTx.TxIn[0].SignatureScript = test.sigScript
		tx := btcutil.NewTx(msgTx)

		err := blockchain.TstCheckSerializedHeight(tx, test.wantHeight)
		if reflect.TypeOf(err) != reflect.TypeOf(test.err) {
			t.Errorf("checkSerializedHeight #%d wrong error type "+
				"got: %v <%T>, want: %T", i, err, err, test.err)
			continue
		}

		if rerr, ok := err.(blockchain.RuleError); ok {
			trerr := test.err.(blockchain.RuleError)
			if rerr.ErrorCode != trerr.ErrorCode {
				t.Errorf("checkSerializedHeight #%d wrong "+
					"error code got: %v, want: %v", i,
					rerr.ErrorCode, trerr.ErrorCode)
				continue
			}
		}
	}
}

func TestInsertsCreditsDebitsRollbacks(t *testing.T) {
	t.Parallel()

	// Create a double spend of the received blockchain transaction.
	dupRecvTx, _ := btcutil.NewTxFromBytes(TstRecvSerializedTx)
	// Switch txout amount to 1 BTC.  Transaction store doesn't
	// validate txs, so this is fine for testing a double spend
	// removal.
	TstDupRecvAmount := int64(1e8)
	newDupMsgTx := dupRecvTx.MsgTx()
	newDupMsgTx.TxOut[0].Value = TstDupRecvAmount
	TstDoubleSpendTx := btcutil.NewTx(newDupMsgTx)
	TstDoubleSpendSerializedTx := serializeTx(TstDoubleSpendTx)

	// Create a "signed" (with invalid sigs) tx that spends output 0 of
	// the double spend.
	spendingTx := wire.NewMsgTx()
	spendingTxIn := wire.NewTxIn(wire.NewOutPoint(TstDoubleSpendTx.Hash(), 0), []byte{0, 1, 2, 3, 4})
	spendingTx.AddTxIn(spendingTxIn)
	spendingTxOut1 := wire.NewTxOut(1e7, []byte{5, 6, 7, 8, 9})
	spendingTxOut2 := wire.NewTxOut(9e7, []byte{10, 11, 12, 13, 14})
	spendingTx.AddTxOut(spendingTxOut1)
	spendingTx.AddTxOut(spendingTxOut2)
	TstSpendingTx := btcutil.NewTx(spendingTx)
	TstSpendingSerializedTx := serializeTx(TstSpendingTx)
	var _ = TstSpendingTx

	tests := []struct {
		name     string
		f        func(*Store) (*Store, error)
		bal, unc btcutil.Amount
		unspents map[wire.OutPoint]struct{}
		unmined  map[chainhash.Hash]struct{}
	}{
		{
			name: "new store",
			f: func(s *Store) (*Store, error) {
				return s, nil
			},
			bal:      0,
			unc:      0,
			unspents: map[wire.OutPoint]struct{}{},
			unmined:  map[chainhash.Hash]struct{}{},
		},
		{
			name: "txout insert",
			f: func(s *Store) (*Store, error) {
				rec, err := NewTxRecord(TstRecvSerializedTx, time.Now())
				if err != nil {
					return nil, err
				}
				err = s.InsertTx(rec, nil)
				if err != nil {
					return nil, err
				}

				err = s.AddCredit(rec, nil, 0, false)
				return s, err
			},
			bal: 0,
			unc: btcutil.Amount(TstRecvTx.MsgTx().TxOut[0].Value),
			unspents: map[wire.OutPoint]struct{}{
				wire.OutPoint{
					Hash:  *TstRecvTx.Hash(),
					Index: 0,
				}: {},
			},
			unmined: map[chainhash.Hash]struct{}{
				*TstRecvTx.Hash(): {},
			},
		},
		{
			name: "insert duplicate unconfirmed",
			f: func(s *Store) (*Store, error) {
				rec, err := NewTxRecord(TstRecvSerializedTx, time.Now())
				if err != nil {
					return nil, err
				}
				err = s.InsertTx(rec, nil)
				if err != nil {
					return nil, err
				}

				err = s.AddCredit(rec, nil, 0, false)
				return s, err
			},
			bal: 0,
			unc: btcutil.Amount(TstRecvTx.MsgTx().TxOut[0].Value),
			unspents: map[wire.OutPoint]struct{}{
				wire.OutPoint{
					Hash:  *TstRecvTx.Hash(),
					Index: 0,
				}: {},
			},
			unmined: map[chainhash.Hash]struct{}{
				*TstRecvTx.Hash(): {},
			},
		},
		{
			name: "confirmed txout insert",
//.........這裏部分代碼省略.........

// createTxIn pulls the outpoint out of the funding TxOut and uses it as a reference
// for the txin that will be placed in a new transaction.
func createTxIn(outpoint *wire.OutPoint) *wire.TxIn {
	// The second arg is the txin's signature script, which we are leaving empty
	// until the entire transaction is ready.
	txin := wire.NewTxIn(outpoint, []byte{})
	return txin
}

// InsertBlock inserts raw block and transaction data from a block into the
// database.  The first block inserted into the database will be treated as the
// genesis block.  Every subsequent block insert requires the referenced parent
// block to already exist.
func (db *LevelDb) InsertBlock(block *btcutil.Block) (height int64, rerr error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()
	defer func() {
		if rerr == nil {
			rerr = db.processBatches()
		} else {
			db.lBatch().Reset()
		}
	}()

	blocksha := block.Sha()
	mblock := block.MsgBlock()
	rawMsg, err := block.Bytes()
	if err != nil {
		log.Warnf("Failed to obtain raw block sha %v", blocksha)
		return 0, err
	}
	txloc, err := block.TxLoc()
	if err != nil {
		log.Warnf("Failed to obtain raw block sha %v", blocksha)
		return 0, err
	}

	// Insert block into database
	newheight, err := db.insertBlockData(blocksha, &mblock.Header.PrevBlock,
		rawMsg)
	if err != nil {
		log.Warnf("Failed to insert block %v %v %v", blocksha,
			&mblock.Header.PrevBlock, err)
		return 0, err
	}

	// At least two blocks in the long past were generated by faulty
	// miners, the sha of the transaction exists in a previous block,
	// detect this condition and 'accept' the block.
	for txidx, tx := range mblock.Transactions {
		txsha, err := block.TxSha(txidx)
		if err != nil {
			log.Warnf("failed to compute tx name block %v idx %v err %v", blocksha, txidx, err)
			return 0, err
		}
		spentbuflen := (len(tx.TxOut) + 7) / 8
		spentbuf := make([]byte, spentbuflen, spentbuflen)
		if len(tx.TxOut)%8 != 0 {
			for i := uint(len(tx.TxOut) % 8); i < 8; i++ {
				spentbuf[spentbuflen-1] |= (byte(1) << i)
			}
		}

		err = db.insertTx(txsha, newheight, txloc[txidx].TxStart, txloc[txidx].TxLen, spentbuf)
		if err != nil {
			log.Warnf("block %v idx %v failed to insert tx %v %v err %v", blocksha, newheight, &txsha, txidx, err)
			return 0, err
		}

		// Some old blocks contain duplicate transactions
		// Attempt to cleanly bypass this problem by marking the
		// first as fully spent.
		// http://blockexplorer.com/b/91812 dup in 91842
		// http://blockexplorer.com/b/91722 dup in 91880
		if newheight == 91812 {
			dupsha, err := wire.NewShaHashFromStr("d5d27987d2a3dfc724e359870c6644b40e497bdc0589a033220fe15429d88599")
			if err != nil {
				panic("invalid sha string in source")
			}
			if txsha.IsEqual(dupsha) {
				// marking TxOut[0] as spent
				po := wire.NewOutPoint(dupsha, 0)
				txI := wire.NewTxIn(po, []byte("garbage"))

				var spendtx wire.MsgTx
				spendtx.AddTxIn(txI)
				err = db.doSpend(&spendtx)
				if err != nil {
					log.Warnf("block %v idx %v failed to spend tx %v %v err %v", blocksha, newheight, &txsha, txidx, err)
				}
			}
		}
		if newheight == 91722 {
			dupsha, err := wire.NewShaHashFromStr("e3bf3d07d4b0375638d5f1db5255fe07ba2c4cb067cd81b84ee974b6585fb468")
			if err != nil {
				panic("invalid sha string in source")
			}
			if txsha.IsEqual(dupsha) {
				// marking TxOut[0] as spent
				po := wire.NewOutPoint(dupsha, 0)
				txI := wire.NewTxIn(po, []byte("garbage"))

				var spendtx wire.MsgTx
				spendtx.AddTxIn(txI)
				err = db.doSpend(&spendtx)
				if err != nil {
					log.Warnf("block %v idx %v failed to spend tx %v %v err %v", blocksha, newheight, &txsha, txidx, err)
				}
			}
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
		// Read the slice length
		l := io.LimitReader(r, int64(blobLength))
		*e, err = ioutil.ReadAll(l)
		if err != nil {
			return err
		}
		if len(*e) != int(blobLength) {
			return fmt.Errorf("EOF: Slice length mismatch.")
		}
		return nil
	case *PkScript:
		// Get the script length first
		var scriptLength uint8
		err = readElement(r, &scriptLength)
		if err != nil {
			return err
		}

		if scriptLength > 25 {
			return fmt.Errorf("PkScript too long!")
		}

		// Read the script length
		l := io.LimitReader(r, int64(scriptLength))
		*e, err = ioutil.ReadAll(l)
		if err != nil {
			return err
		}
		if len(*e) != int(scriptLength) {
			return fmt.Errorf("EOF: Signature length mismatch.")
		}
		return nil
	case *string:
		// Get the string length first
		var strlen uint16
		err = readElement(r, &strlen)
		if err != nil {
			return err
		}
		// Read the string for the length
		l := io.LimitReader(r, int64(strlen))
		b, err := ioutil.ReadAll(l)
		if len(b) != int(strlen) {
			return fmt.Errorf("EOF: String length mismatch.")
		}
		*e = string(b)
		if err != nil {
			return err
		}
		return nil
	case *[]*wire.TxIn:
		// Read the size (1-byte number of txins)
		var numScripts uint8
		err = readElement(r, &numScripts)
		if err != nil {
			return err
		}
		if numScripts > 127 {
			return fmt.Errorf("Too many txins")
		}

		// Append the actual TxIns
		var txins []*wire.TxIn
		for i := uint8(0); i < numScripts; i++ {
			outpoint := new(wire.OutPoint)
			txin := wire.NewTxIn(outpoint, nil)
			err = readElement(r, &txin)
			if err != nil {
				return err
			}
			txins = append(txins, txin)
		}
		*e = *&txins
		return nil
	case **wire.TxIn:
		// Hash
		var h [32]byte
		_, err = io.ReadFull(r, h[:])
		if err != nil {
			return err
		}
		hash, err := wire.NewShaHash(h[:])
		if err != nil {
			return err
		}
		(*e).PreviousOutPoint.Hash = *hash
		// Index
		var idxBytes [4]byte
		_, err = io.ReadFull(r, idxBytes[:])
		if err != nil {
			return err
		}
		(*e).PreviousOutPoint.Index = binary.BigEndian.Uint32(idxBytes[:])
		return nil
	default:
		return fmt.Errorf("Unknown type in readElement: %T", e)
	}

	return nil
}

// newBobNode generates a test "ln node" to interact with Alice (us). For the
// funding transaction, bob has a single output totaling 7BTC. For our basic
// test, he'll fund the channel with 5BTC, leaving 2BTC to the change output.
// TODO(roasbeef): proper handling of change etc.
func newBobNode(miner *rpctest.Harness) (*bobNode, error) {
	// First, parse Bob's priv key in order to obtain a key he'll use for the
	// multi-sig funding transaction.
	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), bobsPrivKey)

	// Next, generate an output redeemable by bob.
	bobAddrPk, err := btcutil.NewAddressPubKey(privKey.PubKey().SerializeCompressed(),
		miner.ActiveNet)
	if err != nil {
		return nil, err
	}
	bobAddr := bobAddrPk.AddressPubKeyHash()
	bobAddrScript, err := txscript.PayToAddrScript(bobAddr)
	if err != nil {
		return nil, err
	}

	// Give bobNode one 7 BTC output for use in creating channels.
	outputMap := map[string]btcutil.Amount{
		bobAddr.String(): btcutil.Amount(7e8),
	}
	mainTxid, err := miner.CoinbaseSpend(outputMap)
	if err != nil {
		return nil, err
	}

	// Mine a block in order to include the above output in a block. During
	// the reservation workflow, we currently test to ensure that the funding
	// output we're given actually exists.
	if _, err := miner.Node.Generate(1); err != nil {
		return nil, err
	}

	// Grab the transaction in order to locate the output index to Bob.
	tx, err := miner.Node.GetRawTransaction(mainTxid)
	if err != nil {
		return nil, err
	}
	found, index := findScriptOutputIndex(tx.MsgTx(), bobAddrScript)
	if !found {
		return nil, fmt.Errorf("output to bob never created")
	}

	prevOut := wire.NewOutPoint(mainTxid, index)
	// TODO(roasbeef): When the chain rpc is hooked in, assert bob's output
	// actually exists and it unspent in the chain.
	bobTxIn := wire.NewTxIn(prevOut, nil)

	// Using bobs priv key above, create a change output he can spend.
	bobChangeOutput := wire.NewTxOut(2*1e8, bobAddrScript)

	// Bob's initial revocation hash is just his private key with the first
	// byte changed...
	var revocation [20]byte
	copy(revocation[:], bobsPrivKey)
	revocation[0] = 0xff

	// His ID is just as creative...
	var id [wire.HashSize]byte
	id[0] = 0xff

	return &bobNode{
		id:               id,
		privKey:          privKey,
		channelKey:       pubKey,
		deliveryAddress:  bobAddr,
		revocation:       revocation,
		delay:            5,
		availableOutputs: []*wire.TxIn{bobTxIn},
		changeOutputs:    []*wire.TxOut{bobChangeOutput},
	}, nil
}

	// Privkey: 5b18f5049efd9d3aff1fb9a06506c0b809fb71562b6ecd02f6c5b3ab298f3b0f
	// PKhash: miky84cHvLuk6jcT6GsSbgHR8d7eZCu9Qc
	changePkScript, _ = hex.DecodeString("76a914238ee44bb5c8c1314dd03974a17ec6c406fdcb8388ac")

	// echo -n | openssl sha256
	// This stuff gets reversed!!!
	shaHash1Bytes, _ = hex.DecodeString("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
	shaHash1, _      = wire.NewShaHash(shaHash1Bytes)
	outpoint1        = wire.NewOutPoint(shaHash1, 0)
	// echo | openssl sha256
	// This stuff gets reversed!!!
	shaHash2Bytes, _ = hex.DecodeString("01ba4719c80b6fe911b091a7c05124b64eeece964e09c058ef8f9805daca546b")
	shaHash2, _      = wire.NewShaHash(shaHash2Bytes)
	outpoint2        = wire.NewOutPoint(shaHash2, 1)
	// create inputs from outpoint1 and outpoint2
	inputs = []*wire.TxIn{wire.NewTxIn(outpoint1, nil), wire.NewTxIn(outpoint2, nil)}

	// Commitment Signature
	tx           = wire.NewMsgTx()
	emptybytes   = new([]byte)
	sigStr, _    = txscript.RawTxInSignature(tx, 0, *emptybytes, txscript.SigHashAll, privKey)
	commitSig, _ = btcec.ParseSignature(sigStr, btcec.S256())

	// Funding TX Sig 1
	sig1privKeyBytes, _ = hex.DecodeString("927f5827d75dd2addeb532c0fa5ac9277565f981dd6d0d037b422be5f60bdbef")
	sig1privKey, _      = btcec.PrivKeyFromBytes(btcec.S256(), sig1privKeyBytes)
	sigStr1, _          = txscript.RawTxInSignature(tx, 0, *emptybytes, txscript.SigHashAll, sig1privKey)
	commitSig1, _       = btcec.ParseSignature(sigStr1, btcec.S256())
	// Funding TX Sig 2
	sig2privKeyBytes, _ = hex.DecodeString("8a4ad188f6f4000495b765cfb6ffa591133a73019c45428ddd28f53bab551847")
	sig2privKey, _      = btcec.PrivKeyFromBytes(btcec.S256(), sig2privKeyBytes)

// fundTx attempts to fund a transaction sending amt bitcoin. The coins are
// selected such that the final amount spent pays enough fees as dictated by
// the passed fee rate. The passed fee rate should be expressed in
// satoshis-per-byte.
//
// NOTE: The memWallet's mutex must be held when this function is called.
func (m *memWallet) fundTx(tx *wire.MsgTx, amt btcutil.Amount, feeRate btcutil.Amount) error {
	const (
		// spendSize is the largest number of bytes of a sigScript
		// which spends a p2pkh output: OP_DATA_73 <sig> OP_DATA_33 <pubkey>
		spendSize = 1 + 73 + 1 + 33
	)

	var (
		amtSelected btcutil.Amount
		txSize      int
	)

	for outPoint, utxo := range m.utxos {
		// Skip any outputs that are still currently immature or are
		// currently locked.
		if !utxo.isMature(m.currentHeight) || utxo.isLocked {
			continue
		}

		amtSelected += utxo.value

		// Add the selected output to the transaction, updating the
		// current tx size while accounting for the size of the future
		// sigScript.
		tx.AddTxIn(wire.NewTxIn(&outPoint, nil))
		txSize = tx.SerializeSize() + spendSize*len(tx.TxIn)

		// Calculate the fee required for the txn at this point
		// observing the specified fee rate. If we don't have enough
		// coins from he current amount selected to pay the fee, then
		// continue to grab more coins.
		reqFee := btcutil.Amount(txSize * int(feeRate))
		if amtSelected-reqFee < amt {
			continue
		}

		// If we have any change left over, then add an additional
		// output to the transaction reserved for change.
		changeVal := amtSelected - amt - reqFee
		if changeVal > 0 {
			addr, err := m.newAddress()
			if err != nil {
				return err
			}
			pkScript, err := txscript.PayToAddrScript(addr)
			if err != nil {
				return err
			}
			changeOutput := &wire.TxOut{
				Value:    int64(changeVal),
				PkScript: pkScript,
			}
			tx.AddTxOut(changeOutput)
		}

		return nil
	}

	// If we've reached this point, then coin selection failed due to an
	// insufficient amount of coins.
	return fmt.Errorf("not enough funds for coin selection")
}