lnd/utxonursery_test.go

// +build !rpctest

package main

import (
	"bytes"
	"fmt"
	"github.com/lightningnetwork/lnd/channeldb"
	"io/ioutil"
	"reflect"
	"sync"
	"testing"
	"time"

	"github.com/btcsuite/btcd/btcec"
	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcd/txscript"
	"github.com/btcsuite/btcd/wire"
	"github.com/btcsuite/btcutil"
	"github.com/lightningnetwork/lnd/chainntnfs"
	"github.com/lightningnetwork/lnd/lnwallet"
)

var (
	outPoints = []wire.OutPoint{
		{
			Hash: [chainhash.HashSize]byte{
				0x51, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
				0x48, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
				0x2d, 0xe7, 0x93, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
				0x1f, 0xb, 0x4c, 0xf9, 0x9e, 0xc5, 0x8c, 0xe9,
			},
			Index: 9,
		},
		{
			Hash: [chainhash.HashSize]byte{
				0xb7, 0x94, 0x38, 0x5f, 0x2d, 0x1e, 0xf7, 0xab,
				0x4d, 0x92, 0x73, 0xd1, 0x90, 0x63, 0x81, 0xb4,
				0x4f, 0x2f, 0x6f, 0x25, 0x88, 0xa3, 0xef, 0xb9,
				0x6a, 0x49, 0x18, 0x83, 0x31, 0x98, 0x47, 0x53,
			},
			Index: 49,
		},
		{
			Hash: [chainhash.HashSize]byte{
				0x81, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
				0x63, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
				0x0d, 0xe7, 0x95, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
				0x1e, 0xb, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
			},
			Index: 23,
		},
		{
			Hash: [chainhash.HashSize]byte{
				0x1e, 0xb, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
				0x81, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
				0x0d, 0xe7, 0x95, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
				0x63, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
			},
			Index: 30,
		},
		{
			Hash: [chainhash.HashSize]byte{
				0x0d, 0xe7, 0x95, 0xe4, 0xfc, 0xd2, 0xc6, 0xda,
				0xb7, 0x25, 0xb8, 0x4d, 0x63, 0x59, 0xe6, 0x96,
				0x31, 0x13, 0xa1, 0x17, 0x81, 0xb6, 0x37, 0xd8,
				0x1e, 0x0b, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
			},
			Index: 2,
		},
		{
			Hash: [chainhash.HashSize]byte{
				0x48, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
				0x51, 0xb6, 0x37, 0xd8, 0x1f, 0x0b, 0x4c, 0xf9,
				0x9e, 0xc5, 0x8c, 0xe9, 0xfc, 0xd2, 0xc6, 0xda,
				0x2d, 0xe7, 0x93, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
			},
			Index: 9,
		},
	}

	keys = [][]byte{
		{0x04, 0x11, 0xdb, 0x93, 0xe1, 0xdc, 0xdb, 0x8a,
			0x01, 0x6b, 0x49, 0x84, 0x0f, 0x8c, 0x53, 0xbc, 0x1e,
			0xb6, 0x8a, 0x38, 0x2e, 0x97, 0xb1, 0x48, 0x2e, 0xca,
			0xd7, 0xb1, 0x48, 0xa6, 0x90, 0x9a, 0x5c, 0xb2, 0xe0,
			0xea, 0xdd, 0xfb, 0x84, 0xcc, 0xf9, 0x74, 0x44, 0x64,
			0xf8, 0x2e, 0x16, 0x0b, 0xfa, 0x9b, 0x8b, 0x64, 0xf9,
			0xd4, 0xc0, 0x3f, 0x99, 0x9b, 0x86, 0x43, 0xf6, 0x56,
			0xb4, 0x12, 0xa3,
		},
		{0x07, 0x11, 0xdb, 0x93, 0xe1, 0xdc, 0xdb, 0x8a,
			0x01, 0x6b, 0x49, 0x84, 0x0f, 0x8c, 0x53, 0xbc, 0x1e,
			0xb6, 0x8a, 0x38, 0x2e, 0x97, 0xb1, 0x48, 0x2e, 0xca,
			0xd7, 0xb1, 0x48, 0xa6, 0x90, 0x9a, 0x5c, 0xb2, 0xe0,
			0xea, 0xdd, 0xfb, 0x84, 0xcc, 0xf9, 0x74, 0x44, 0x64,
			0xf8, 0x2e, 0x16, 0x0b, 0xfa, 0x9b, 0x8b, 0x64, 0xf9,
			0xd4, 0xc0, 0x3f, 0x99, 0x9b, 0x86, 0x43, 0xf6, 0x56,
			0xb4, 0x12, 0xa3,
		},
		{0x02, 0xce, 0x0b, 0x14, 0xfb, 0x84, 0x2b, 0x1b,
			0xa5, 0x49, 0xfd, 0xd6, 0x75, 0xc9, 0x80, 0x75, 0xf1,
			0x2e, 0x9c, 0x51, 0x0f, 0x8e, 0xf5, 0x2b, 0xd0, 0x21,
			0xa9, 0xa1, 0xf4, 0x80, 0x9d, 0x3b, 0x4d,
		},
	}

	signDescriptors = []lnwallet.SignDescriptor{
		{
			SingleTweak: []byte{
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02,
			},
			WitnessScript: []byte{
				0x00, 0x14, 0xee, 0x91, 0x41, 0x7e, 0x85, 0x6c, 0xde,
				0x10, 0xa2, 0x91, 0x1e, 0xdc, 0xbd, 0xbd, 0x69, 0xe2,
				0xef, 0xb5, 0x71, 0x48,
			},
			Output: &wire.TxOut{
				Value: 5000000000,
				PkScript: []byte{
					0x41, // OP_DATA_65
					0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
					0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
					0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
					0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
					0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
					0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
					0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
					0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
					0xa6, // 65-byte signature
					0xac, // OP_CHECKSIG
				},
			},
			HashType: txscript.SigHashAll,
		},
		{
			SingleTweak: []byte{
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02,
			},
			WitnessScript: []byte{
				0x00, 0x14, 0xee, 0x91, 0x41, 0x7e, 0x85, 0x6c, 0xde,
				0x10, 0xa2, 0x91, 0x1e, 0xdc, 0xbd, 0xbd, 0x69, 0xe2,
				0xef, 0xb5, 0x71, 0x48,
			},
			Output: &wire.TxOut{
				Value: 5000000000,
				PkScript: []byte{
					0x41, // OP_DATA_65
					0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
					0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
					0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
					0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
					0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
					0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
					0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
					0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
					0xa6, // 65-byte signature
					0xac, // OP_CHECKSIG
				},
			},
			HashType: txscript.SigHashAll,
		},
		{
			SingleTweak: []byte{
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
				0x02, 0x02, 0x02, 0x02, 0x02,
			},
			WitnessScript: []byte{
				0x00, 0x14, 0xee, 0x91, 0x41, 0x7e, 0x85, 0x6c, 0xde,
				0x10, 0xa2, 0x91, 0x1e, 0xdc, 0xbd, 0xbd, 0x69, 0xe2,
				0xef, 0xb5, 0x71, 0x48,
			},
			Output: &wire.TxOut{
				Value: 5000000000,
				PkScript: []byte{
					0x41, // OP_DATA_65
					0x04, 0xd6, 0x4b, 0xdf, 0xd0, 0x9e, 0xb1, 0xc5,
					0xfe, 0x29, 0x5a, 0xbd, 0xeb, 0x1d, 0xca, 0x42,
					0x81, 0xbe, 0x98, 0x8e, 0x2d, 0xa0, 0xb6, 0xc1,
					0xc6, 0xa5, 0x9d, 0xc2, 0x26, 0xc2, 0x86, 0x24,
					0xe1, 0x81, 0x75, 0xe8, 0x51, 0xc9, 0x6b, 0x97,
					0x3d, 0x81, 0xb0, 0x1c, 0xc3, 0x1f, 0x04, 0x78,
					0x34, 0xbc, 0x06, 0xd6, 0xd6, 0xed, 0xf6, 0x20,
					0xd1, 0x84, 0x24, 0x1a, 0x6a, 0xed, 0x8b, 0x63,
					0xa6, // 65-byte signature
					0xac, // OP_CHECKSIG
				},
			},
			HashType: txscript.SigHashAll,
		},
	}

	kidOutputs = []kidOutput{
		{
			breachedOutput: breachedOutput{
				amt:         btcutil.Amount(13e7),
				outpoint:    outPoints[1],
				witnessType: lnwallet.CommitmentTimeLock,
			},
			originChanPoint:  outPoints[0],
			blocksToMaturity: uint32(42),
			confHeight:       uint32(1000),
		},

		{
			breachedOutput: breachedOutput{
				amt:         btcutil.Amount(24e7),
				outpoint:    outPoints[2],
				witnessType: lnwallet.CommitmentTimeLock,
			},
			originChanPoint:  outPoints[0],
			blocksToMaturity: uint32(42),
			confHeight:       uint32(1000),
		},

		{
			breachedOutput: breachedOutput{
				amt:         btcutil.Amount(2e5),
				outpoint:    outPoints[3],
				witnessType: lnwallet.CommitmentTimeLock,
			},
			originChanPoint:  outPoints[0],
			blocksToMaturity: uint32(28),
			confHeight:       uint32(500),
		},

		{
			breachedOutput: breachedOutput{
				amt:         btcutil.Amount(10e6),
				outpoint:    outPoints[4],
				witnessType: lnwallet.CommitmentTimeLock,
			},
			originChanPoint:  outPoints[0],
			blocksToMaturity: uint32(28),
			confHeight:       uint32(500),
		},
	}

	babyOutputs = []babyOutput{
		{
			kidOutput: kidOutputs[1],
			expiry:    3829,
			timeoutTx: timeoutTx,
		},
		{
			kidOutput: kidOutputs[2],
			expiry:    4,
			timeoutTx: timeoutTx,
		},
		{
			kidOutput: kidOutputs[3],
			expiry:    4,
			timeoutTx: timeoutTx,
		},
	}

	// Dummy timeout tx used to test serialization, borrowed from btcd
	// msgtx_test
	timeoutTx = &wire.MsgTx{
		Version: 1,
		TxIn: []*wire.TxIn{
			{
				PreviousOutPoint: wire.OutPoint{
					Hash: chainhash.Hash{
						0xa5, 0x33, 0x52, 0xd5, 0x13, 0x57, 0x66, 0xf0,
						0x30, 0x76, 0x59, 0x74, 0x18, 0x26, 0x3d, 0xa2,
						0xd9, 0xc9, 0x58, 0x31, 0x59, 0x68, 0xfe, 0xa8,
						0x23, 0x52, 0x94, 0x67, 0x48, 0x1f, 0xf9, 0xcd,
					},
					Index: 19,
				},
				SignatureScript: []byte{},
				Witness: [][]byte{
					{ // 70-byte signature
						0x30, 0x43, 0x02, 0x1f, 0x4d, 0x23, 0x81, 0xdc,
						0x97, 0xf1, 0x82, 0xab, 0xd8, 0x18, 0x5f, 0x51,
						0x75, 0x30, 0x18, 0x52, 0x32, 0x12, 0xf5, 0xdd,
						0xc0, 0x7c, 0xc4, 0xe6, 0x3a, 0x8d, 0xc0, 0x36,
						0x58, 0xda, 0x19, 0x02, 0x20, 0x60, 0x8b, 0x5c,
						0x4d, 0x92, 0xb8, 0x6b, 0x6d, 0xe7, 0xd7, 0x8e,
						0xf2, 0x3a, 0x2f, 0xa7, 0x35, 0xbc, 0xb5, 0x9b,
						0x91, 0x4a, 0x48, 0xb0, 0xe1, 0x87, 0xc5, 0xe7,
						0x56, 0x9a, 0x18, 0x19, 0x70, 0x01,
					},
					{ // 33-byte serialize pub key
						0x03, 0x07, 0xea, 0xd0, 0x84, 0x80, 0x7e, 0xb7,
						0x63, 0x46, 0xdf, 0x69, 0x77, 0x00, 0x0c, 0x89,
						0x39, 0x2f, 0x45, 0xc7, 0x64, 0x25, 0xb2, 0x61,
						0x81, 0xf5, 0x21, 0xd7, 0xf3, 0x70, 0x06, 0x6a,
						0x8f,
					},
				},
				Sequence: 0xffffffff,
			},
		},
		TxOut: []*wire.TxOut{
			{
				Value: 395019,
				PkScript: []byte{ // p2wkh output
					0x00, // Version 0 witness program
					0x14, // OP_DATA_20
					0x9d, 0xda, 0xc6, 0xf3, 0x9d, 0x51, 0xe0, 0x39,
					0x8e, 0x53, 0x2a, 0x22, 0xc4, 0x1b, 0xa1, 0x89,
					0x40, 0x6a, 0x85, 0x23, // 20-byte pub key hash
				},
			},
		},
	}

	testChanPoint      = wire.OutPoint{}
	defaultTestTimeout = 5 * time.Second
)

func init() {
	// Finish initializing our test vectors by parsing the desired public keys and
	// properly populating the sign descriptors of all baby and kid outputs.
	for i := range signDescriptors {
		pk, err := btcec.ParsePubKey(keys[i], btcec.S256())
		if err != nil {
			panic(fmt.Sprintf("unable to parse pub key during init: %v", err))
		}
		signDescriptors[i].KeyDesc.PubKey = pk

	}
	for i := range kidOutputs {
		isd := i % len(signDescriptors)
		kidOutputs[i].signDesc = signDescriptors[isd]
	}

	for i := range babyOutputs {
		isd := i % len(signDescriptors)
		babyOutputs[i].kidOutput.signDesc = signDescriptors[isd]
	}

	initIncubateTests()
}

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

	for i, kid := range kidOutputs {
		var b bytes.Buffer
		if err := kid.Encode(&b); err != nil {
			t.Fatalf("Encode #%d: unable to serialize "+
				"kid output: %v", i, err)
		}

		var deserializedKid kidOutput
		if err := deserializedKid.Decode(&b); err != nil {
			t.Fatalf("Decode #%d: unable to deserialize "+
				"kid output: %v", i, err)
		}

		if !reflect.DeepEqual(kid, deserializedKid) {
			t.Fatalf("DeepEqual #%d: unexpected kidOutput, "+
				"want %+v, got %+v",
				i, kid, deserializedKid)
		}
	}
}

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

	for i, baby := range babyOutputs {
		var b bytes.Buffer
		if err := baby.Encode(&b); err != nil {
			t.Fatalf("Encode #%d: unable to serialize "+
				"baby output: %v", i, err)
		}

		var deserializedBaby babyOutput
		if err := deserializedBaby.Decode(&b); err != nil {
			t.Fatalf("Decode #%d: unable to deserialize "+
				"baby output: %v", i, err)
		}

		if !reflect.DeepEqual(baby, deserializedBaby) {
			t.Fatalf("DeepEqual #%d: unexpected babyOutput, "+
				"want %+v, got %+v",
				i, baby, deserializedBaby)
		}

	}
}

type nurseryTestContext struct {
	nursery     *utxoNursery
	notifier    *nurseryMockNotifier
	publishChan chan chainhash.Hash
	store       *nurseryStoreInterceptor
}

func createNurseryTestContext(t *testing.T) *nurseryTestContext {
	// Create a temporary database and connect nurseryStore to it. The
	// alternative, mocking nurseryStore, is not chosen because there is
	// still considerable logic in the store.

	tempDirName, err := ioutil.TempDir("", "channeldb")
	if err != nil {
		t.Fatalf("unable to create temp dir: %v", err)
	}

	cdb, err := channeldb.Open(tempDirName)
	if err != nil {
		t.Fatalf("unable to open channeldb: %v", err)
	}

	store, err := newNurseryStore(&chainhash.Hash{}, cdb)
	if err != nil {
		t.Fatal(err)
	}

	// Wrap the store in an inceptor to be able to wait for events in this
	// test.
	storeIntercepter := newNurseryStoreInterceptor(store)

	notifier := newNurseryMockNotifier(t)

	cfg := NurseryConfig{
		Notifier: notifier,
		DB:       cdb,
		Store:    storeIntercepter,
		ChainIO:  &mockChainIO{},
		GenSweepScript: func() ([]byte, error) {
			return []byte{}, nil
		},
		Estimator: &mockFeeEstimator{},
		Signer:    &nurseryMockSigner{},
	}

	publishChan := make(chan chainhash.Hash, 1)
	cfg.PublishTransaction = func(tx *wire.MsgTx) error {
		t.Logf("Publishing tx %v", tx.TxHash())
		publishChan <- tx.TxHash()
		return nil
	}

	nursery := newUtxoNursery(&cfg)
	nursery.Start()

	return &nurseryTestContext{
		nursery:     nursery,
		notifier:    notifier,
		store:       storeIntercepter,
		publishChan: publishChan,
	}
}

func createOutgoingRes(onLocalCommitment bool) *lnwallet.OutgoingHtlcResolution {
	// Set up an outgoing htlc resolution to hand off to nursery.
	closeTx := &wire.MsgTx{}

	htlcOp := wire.OutPoint{
		Hash:  closeTx.TxHash(),
		Index: 0,
	}

	outgoingRes := lnwallet.OutgoingHtlcResolution{
		Expiry: 125,
		SweepSignDesc: lnwallet.SignDescriptor{
			Output: &wire.TxOut{
				Value: 10000,
			},
		},
		CsvDelay: 2,
	}

	if onLocalCommitment {
		timeoutTx := &wire.MsgTx{
			TxIn: []*wire.TxIn{
				{
					PreviousOutPoint: htlcOp,
					Witness:          [][]byte{{}},
				},
			},
			TxOut: []*wire.TxOut{
				{},
			},
		}

		outgoingRes.SignedTimeoutTx = timeoutTx
	} else {
		outgoingRes.ClaimOutpoint = htlcOp
	}

	return &outgoingRes
}

func incubateTestOutput(t *testing.T, nursery *utxoNursery,
	onLocalCommitment bool) *lnwallet.OutgoingHtlcResolution {

	outgoingRes := createOutgoingRes(onLocalCommitment)

	// Hand off to nursery.
	err := nursery.IncubateOutputs(
		testChanPoint,
		nil,
		[]lnwallet.OutgoingHtlcResolution{*outgoingRes},
		nil, 0,
	)
	if err != nil {
		t.Fatal(err)
	}

	// IncubateOutputs is executing synchronously and we expect the output
	// to immediately show up in the report.
	expectedStage := uint32(2)
	if onLocalCommitment {
		expectedStage = 1
	}

	// TODO(joostjager): Nursery is currently not reporting this limbo
	// balance.
	if onLocalCommitment {
		assertNurseryReport(t, nursery, 1, expectedStage)
	}

	return outgoingRes
}

func assertNurseryReport(t *testing.T, nursery *utxoNursery,
	expectedNofHtlcs int, expectedStage uint32) {
	report, err := nursery.NurseryReport(&testChanPoint)
	if err != nil {
		t.Fatal(err)
	}

	if len(report.htlcs) != expectedNofHtlcs {
		t.Fatalf("expected %v outputs to be reported, but report "+
			"only contains %v", expectedNofHtlcs, len(report.htlcs))
	}
	htlcReport := report.htlcs[0]
	if htlcReport.stage != expectedStage {
		t.Fatalf("expected htlc be advanced to stage %v, but it is "+
			"reported in stage %v", expectedStage, htlcReport.stage)
	}
}

func assertNurseryReportUnavailable(t *testing.T, nursery *utxoNursery) {
	_, err := nursery.NurseryReport(&testChanPoint)
	if err != ErrContractNotFound {
		t.Fatal("expected report to be unavailable")
	}
}

func TestNurseryOutgoingHtlcSuccessOnLocal(t *testing.T) {
	ctx := createNurseryTestContext(t)

	outgoingRes := incubateTestOutput(t, ctx.nursery, true)

	// Notify arrival of block where HTLC CLTV expires.
	ctx.notifier.notifyEpoch(125)

	// This should trigger nursery to publish the timeout tx.
	select {
	case <-ctx.publishChan:
	case <-time.After(defaultTestTimeout):
		t.Fatalf("tx not published")
	}

	// Confirm the timeout tx. This should promote the HTLC to KNDR state.
	timeoutTxHash := outgoingRes.SignedTimeoutTx.TxHash()
	if err := ctx.notifier.confirmTx(&timeoutTxHash, 126); err != nil {
		t.Fatal(err)
	}

	// Wait for output to be promoted in store to KNDR.
	select {
	case <-ctx.store.cribToKinderChan:
	case <-time.After(defaultTestTimeout):
		t.Fatalf("output not promoted to KNDR")
	}

	// Notify arrival of block where second level HTLC unlocks.
	ctx.notifier.notifyEpoch(128)

	// Check final sweep into wallet.
	testSweep(t, ctx)
}

func TestNurseryOutgoingHtlcSuccessOnRemote(t *testing.T) {
	ctx := createNurseryTestContext(t)

	outgoingRes := incubateTestOutput(t, ctx.nursery, false)

	// Notify confirmation of the commitment tx. Is only listened to when
	// resolving remote commitment tx.
	//
	// TODO(joostjager): This is probably not correct?
	err := ctx.notifier.confirmTx(&outgoingRes.ClaimOutpoint.Hash, 124)
	if err != nil {
		t.Fatal(err)
	}

	// Wait for output to be promoted from PSCL to KNDR.
	select {
	case <-ctx.store.preschoolToKinderChan:
	case <-time.After(defaultTestTimeout):
		t.Fatalf("output not promoted to KNDR")
	}

	// Notify arrival of block where HTLC CLTV expires.
	ctx.notifier.notifyEpoch(125)

	// Check final sweep into wallet.
	testSweep(t, ctx)
}

func testSweep(t *testing.T, ctx *nurseryTestContext) {
	// Wait for nursery to publish the sweep tx.
	var sweepTxHash chainhash.Hash
	select {
	case sweepTxHash = <-ctx.publishChan:
	case <-time.After(defaultTestTimeout):
		t.Fatalf("sweep tx not published")
	}

	// Verify stage in nursery report. HTLCs should now both still be in
	// stage two.
	assertNurseryReport(t, ctx.nursery, 1, 2)

	// Confirm the sweep tx.
	err := ctx.notifier.confirmTx(&sweepTxHash, 129)
	if err != nil {
		t.Fatal(err)
	}

	// Wait for output to be promoted in store to GRAD.
	select {
	case <-ctx.store.graduateKinderChan:
	case <-time.After(defaultTestTimeout):
		t.Fatalf("output not graduated")
	}

	// As there only was one output to graduate, we expect the channel to be
	// closed and no report available anymore.
	assertNurseryReportUnavailable(t, ctx.nursery)
}

type nurseryStoreInterceptor struct {
	ns NurseryStore

	// TODO(joostjager): put more useful info through these channels.
	cribToKinderChan      chan struct{}
	cribToRemoteSpendChan chan struct{}
	graduateKinderChan    chan struct{}
	preschoolToKinderChan chan struct{}
}

func newNurseryStoreInterceptor(ns NurseryStore) *nurseryStoreInterceptor {
	return &nurseryStoreInterceptor{
		ns:                    ns,
		cribToKinderChan:      make(chan struct{}),
		cribToRemoteSpendChan: make(chan struct{}),
		graduateKinderChan:    make(chan struct{}),
		preschoolToKinderChan: make(chan struct{}),
	}
}

func (i *nurseryStoreInterceptor) Incubate(kidOutputs []kidOutput,
	babyOutputs []babyOutput) error {

	return i.ns.Incubate(kidOutputs, babyOutputs)
}

func (i *nurseryStoreInterceptor) CribToKinder(babyOutput *babyOutput) error {
	err := i.ns.CribToKinder(babyOutput)

	i.cribToKinderChan <- struct{}{}

	return err
}

func (i *nurseryStoreInterceptor) PreschoolToKinder(kidOutput *kidOutput) error {
	err := i.ns.PreschoolToKinder(kidOutput)

	i.preschoolToKinderChan <- struct{}{}

	return err
}

func (i *nurseryStoreInterceptor) GraduateKinder(height uint32) error {
	err := i.ns.GraduateKinder(height)

	i.graduateKinderChan <- struct{}{}

	return err
}

func (i *nurseryStoreInterceptor) FetchPreschools() ([]kidOutput, error) {
	return i.ns.FetchPreschools()
}

func (i *nurseryStoreInterceptor) FetchClass(height uint32) (*wire.MsgTx,
	[]kidOutput, []babyOutput, error) {

	return i.ns.FetchClass(height)
}

func (i *nurseryStoreInterceptor) FinalizeKinder(height uint32,
	tx *wire.MsgTx) error {

	return i.ns.FinalizeKinder(height, tx)
}

func (i *nurseryStoreInterceptor) LastFinalizedHeight() (uint32, error) {
	return i.ns.LastFinalizedHeight()
}

func (i *nurseryStoreInterceptor) GraduateHeight(height uint32) error {
	return i.ns.GraduateHeight(height)
}

func (i *nurseryStoreInterceptor) LastGraduatedHeight() (uint32, error) {
	return i.ns.LastGraduatedHeight()
}

func (i *nurseryStoreInterceptor) HeightsBelowOrEqual(height uint32) (
	[]uint32, error) {

	return i.ns.HeightsBelowOrEqual(height)
}

func (i *nurseryStoreInterceptor) ForChanOutputs(chanPoint *wire.OutPoint,
	callback func([]byte, []byte) error) error {

	return i.ns.ForChanOutputs(chanPoint, callback)
}

func (i *nurseryStoreInterceptor) ListChannels() ([]wire.OutPoint, error) {
	return i.ns.ListChannels()
}

func (i *nurseryStoreInterceptor) IsMatureChannel(chanPoint *wire.OutPoint) (
	bool, error) {

	return i.ns.IsMatureChannel(chanPoint)
}

func (i *nurseryStoreInterceptor) RemoveChannel(chanPoint *wire.OutPoint) error {
	return i.ns.RemoveChannel(chanPoint)
}

type mockFeeEstimator struct{}

func (m *mockFeeEstimator) EstimateFeePerKW(
	numBlocks uint32) (lnwallet.SatPerKWeight, error) {

	return lnwallet.SatPerKWeight(10000), nil
}

func (m *mockFeeEstimator) Start() error {
	return nil
}
func (m *mockFeeEstimator) Stop() error {
	return nil
}

type nurseryMockSigner struct {
}

func (m *nurseryMockSigner) SignOutputRaw(tx *wire.MsgTx,
	signDesc *lnwallet.SignDescriptor) ([]byte, error) {

	return []byte{}, nil
}

func (m *nurseryMockSigner) ComputeInputScript(tx *wire.MsgTx,
	signDesc *lnwallet.SignDescriptor) (*lnwallet.InputScript, error) {

	return &lnwallet.InputScript{}, nil
}

type nurseryMockNotifier struct {
	confChannel map[chainhash.Hash]chan *chainntnfs.TxConfirmation
	epochChan   chan *chainntnfs.BlockEpoch
	spendChan   chan *chainntnfs.SpendDetail
	mutex       sync.RWMutex
	t           *testing.T
}

func newNurseryMockNotifier(t *testing.T) *nurseryMockNotifier {
	return &nurseryMockNotifier{
		confChannel: make(map[chainhash.Hash]chan *chainntnfs.TxConfirmation),
		epochChan:   make(chan *chainntnfs.BlockEpoch),
		spendChan:   make(chan *chainntnfs.SpendDetail),
		t:           t,
	}
}

func (m *nurseryMockNotifier) notifyEpoch(height int32) {
	select {
	case m.epochChan <- &chainntnfs.BlockEpoch{
		Height: height,
	}:
	case <-time.After(defaultTestTimeout):
		m.t.Fatal("epoch event not consumed")
	}
}

func (m *nurseryMockNotifier) confirmTx(txid *chainhash.Hash, height uint32) error {
	confirm := &chainntnfs.TxConfirmation{
		BlockHeight: height,
	}
	select {
	case m.getConfChannel(txid) <- confirm:
	case <-time.After(defaultTestTimeout):
		return fmt.Errorf("confirmation not consumed")
	}
	return nil
}

func (m *nurseryMockNotifier) RegisterConfirmationsNtfn(txid *chainhash.Hash,
	_ []byte, numConfs, heightHint uint32) (*chainntnfs.ConfirmationEvent,
	error) {

	return &chainntnfs.ConfirmationEvent{
		Confirmed: m.getConfChannel(txid),
	}, nil
}

func (m *nurseryMockNotifier) getConfChannel(
	txid *chainhash.Hash) chan *chainntnfs.TxConfirmation {

	m.mutex.Lock()
	defer m.mutex.Unlock()

	channel, ok := m.confChannel[*txid]
	if ok {
		return channel
	}
	channel = make(chan *chainntnfs.TxConfirmation)
	m.confChannel[*txid] = channel

	return channel
}

func (m *nurseryMockNotifier) RegisterBlockEpochNtfn(
	bestBlock *chainntnfs.BlockEpoch) (*chainntnfs.BlockEpochEvent, error) {
	return &chainntnfs.BlockEpochEvent{
		Epochs: m.epochChan,
		Cancel: func() {},
	}, nil
}

func (m *nurseryMockNotifier) Start() error {
	return nil
}

func (m *nurseryMockNotifier) Stop() error {
	return nil
}

func (m *nurseryMockNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint,
	_ []byte, heightHint uint32) (*chainntnfs.SpendEvent, error) {

	return &chainntnfs.SpendEvent{
		Spend:  m.spendChan,
		Cancel: func() {},
	}, nil
}