lnd/lntest/itest/lnd_test.go

package itest

import (
	"bytes"
	"context"
	"crypto/rand"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"math"
	"os"
	"strings"
	"testing"
	"time"

	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcd/integration/rpctest"
	"github.com/btcsuite/btcd/rpcclient"
	"github.com/btcsuite/btcd/wire"
	"github.com/btcsuite/btcutil"
	"github.com/btcsuite/btcwallet/wallet"
	"github.com/davecgh/go-spew/spew"
	"github.com/go-errors/errors"
	"github.com/lightningnetwork/lnd/chainreg"
	"github.com/lightningnetwork/lnd/funding"
	"github.com/lightningnetwork/lnd/input"
	"github.com/lightningnetwork/lnd/lncfg"
	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
	"github.com/lightningnetwork/lnd/lntest"
	"github.com/lightningnetwork/lnd/lntest/wait"
	"github.com/lightningnetwork/lnd/lnwallet"
	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
	"github.com/lightningnetwork/lnd/lnwire"
	"github.com/stretchr/testify/require"
)

const (
	// defaultSplitTranches is the default number of tranches we split the
	// test cases into.
	defaultSplitTranches uint = 1

	// defaultRunTranche is the default index of the test cases tranche that
	// we run.
	defaultRunTranche uint = 0
)

var (
	// testCasesSplitParts is the number of tranches the test cases should
	// be split into. By default this is set to 1, so no splitting happens.
	// If this value is increased, then the -runtranche flag must be
	// specified as well to indicate which part should be run in the current
	// invocation.
	testCasesSplitTranches = flag.Uint(
		"splittranches", defaultSplitTranches, "split the test cases "+
			"in this many tranches and run the tranche at "+
			"0-based index specified by the -runtranche flag",
	)

	// testCasesRunTranche is the 0-based index of the split test cases
	// tranche to run in the current invocation.
	testCasesRunTranche = flag.Uint(
		"runtranche", defaultRunTranche, "run the tranche of the "+
			"split test cases with the given (0-based) index",
	)

	// dbBackendFlag specifies the backend to use
	dbBackendFlag = flag.String("dbbackend", "bbolt", "Database backend (bbolt, etcd)")
)

// getTestCaseSplitTranche returns the sub slice of the test cases that should
// be run as the current split tranche as well as the index and slice offset of
// the tranche.
func getTestCaseSplitTranche() ([]*testCase, uint, uint) {
	numTranches := defaultSplitTranches
	if testCasesSplitTranches != nil {
		numTranches = *testCasesSplitTranches
	}
	runTranche := defaultRunTranche
	if testCasesRunTranche != nil {
		runTranche = *testCasesRunTranche
	}

	// There's a special flake-hunt mode where we run the same test multiple
	// times in parallel. In that case the tranche index is equal to the
	// thread ID, but we need to actually run all tests for the regex
	// selection to work.
	threadID := runTranche
	if numTranches == 1 {
		runTranche = 0
	}

	numCases := uint(len(allTestCases))
	testsPerTranche := numCases / numTranches
	trancheOffset := runTranche * testsPerTranche
	trancheEnd := trancheOffset + testsPerTranche
	if trancheEnd > numCases || runTranche == numTranches-1 {
		trancheEnd = numCases
	}

	return allTestCases[trancheOffset:trancheEnd], threadID, trancheOffset
}

func rpcPointToWirePoint(t *harnessTest, chanPoint *lnrpc.ChannelPoint) wire.OutPoint {
	txid, err := lnrpc.GetChanPointFundingTxid(chanPoint)
	if err != nil {
		t.Fatalf("unable to get txid: %v", err)
	}

	return wire.OutPoint{
		Hash:  *txid,
		Index: chanPoint.OutputIndex,
	}
}

// completePaymentRequests sends payments from a lightning node to complete all
// payment requests. If the awaitResponse parameter is true, this function
// does not return until all payments successfully complete without errors.
func completePaymentRequests(ctx context.Context, client lnrpc.LightningClient,
	routerClient routerrpc.RouterClient, paymentRequests []string,
	awaitResponse bool) error {

	// We start by getting the current state of the client's channels. This
	// is needed to ensure the payments actually have been committed before
	// we return.
	ctxt, _ := context.WithTimeout(ctx, defaultTimeout)
	req := &lnrpc.ListChannelsRequest{}
	listResp, err := client.ListChannels(ctxt, req)
	if err != nil {
		return err
	}

	// send sends a payment and returns an error if it doesn't succeeded.
	send := func(payReq string) error {
		ctxc, cancel := context.WithCancel(ctx)
		defer cancel()

		payStream, err := routerClient.SendPaymentV2(
			ctxc,
			&routerrpc.SendPaymentRequest{
				PaymentRequest: payReq,
				TimeoutSeconds: 60,
				FeeLimitMsat:   noFeeLimitMsat,
			},
		)
		if err != nil {
			return err
		}

		resp, err := getPaymentResult(payStream)
		if err != nil {
			return err
		}
		if resp.Status != lnrpc.Payment_SUCCEEDED {
			return errors.New(resp.FailureReason)
		}

		return nil
	}

	// Launch all payments simultaneously.
	results := make(chan error)
	for _, payReq := range paymentRequests {
		payReqCopy := payReq
		go func() {
			err := send(payReqCopy)
			if awaitResponse {
				results <- err
			}
		}()
	}

	// If awaiting a response, verify that all payments succeeded.
	if awaitResponse {
		for range paymentRequests {
			err := <-results
			if err != nil {
				return err
			}
		}
		return nil
	}

	// We are not waiting for feedback in the form of a response, but we
	// should still wait long enough for the server to receive and handle
	// the send before cancelling the request. We wait for the number of
	// updates to one of our channels has increased before we return.
	err = wait.Predicate(func() bool {
		ctxt, _ = context.WithTimeout(ctx, defaultTimeout)
		newListResp, err := client.ListChannels(ctxt, req)
		if err != nil {
			return false
		}

		// If the number of open channels is now lower than before
		// attempting the payments, it means one of the payments
		// triggered a force closure (for example, due to an incorrect
		// preimage). Return early since it's clear the payment was
		// attempted.
		if len(newListResp.Channels) < len(listResp.Channels) {
			return true
		}

		for _, c1 := range listResp.Channels {
			for _, c2 := range newListResp.Channels {
				if c1.ChannelPoint != c2.ChannelPoint {
					continue
				}

				// If this channel has an increased numbr of
				// updates, we assume the payments are
				// committed, and we can return.
				if c2.NumUpdates > c1.NumUpdates {
					return true
				}
			}
		}

		return false
	}, defaultTimeout)
	if err != nil {
		return err
	}

	return nil
}

// makeFakePayHash creates random pre image hash
func makeFakePayHash(t *harnessTest) []byte {
	randBuf := make([]byte, 32)

	if _, err := rand.Read(randBuf); err != nil {
		t.Fatalf("internal error, cannot generate random string: %v", err)
	}

	return randBuf
}

// createPayReqs is a helper method that will create a slice of payment
// requests for the given node.
func createPayReqs(node *lntest.HarnessNode, paymentAmt btcutil.Amount,
	numInvoices int) ([]string, [][]byte, []*lnrpc.Invoice, error) {

	payReqs := make([]string, numInvoices)
	rHashes := make([][]byte, numInvoices)
	invoices := make([]*lnrpc.Invoice, numInvoices)
	for i := 0; i < numInvoices; i++ {
		preimage := make([]byte, 32)
		_, err := rand.Read(preimage)
		if err != nil {
			return nil, nil, nil, fmt.Errorf("unable to generate "+
				"preimage: %v", err)
		}
		invoice := &lnrpc.Invoice{
			Memo:      "testing",
			RPreimage: preimage,
			Value:     int64(paymentAmt),
		}
		ctxt, _ := context.WithTimeout(
			context.Background(), defaultTimeout,
		)
		resp, err := node.AddInvoice(ctxt, invoice)
		if err != nil {
			return nil, nil, nil, fmt.Errorf("unable to add "+
				"invoice: %v", err)
		}

		// Set the payment address in the invoice so the caller can
		// properly use it.
		invoice.PaymentAddr = resp.PaymentAddr

		payReqs[i] = resp.PaymentRequest
		rHashes[i] = resp.RHash
		invoices[i] = invoice
	}
	return payReqs, rHashes, invoices, nil
}

// getChanInfo is a helper method for getting channel info for a node's sole
// channel.
func getChanInfo(ctx context.Context, node *lntest.HarnessNode) (
	*lnrpc.Channel, error) {

	req := &lnrpc.ListChannelsRequest{}
	channelInfo, err := node.ListChannels(ctx, req)
	if err != nil {
		return nil, err
	}
	if len(channelInfo.Channels) != 1 {
		return nil, fmt.Errorf("node should only have a single "+
			"channel, instead it has %v", len(channelInfo.Channels))
	}

	return channelInfo.Channels[0], nil
}

// testGetRecoveryInfo checks whether lnd gives the right information about
// the wallet recovery process.
func testGetRecoveryInfo(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// First, create a new node with strong passphrase and grab the mnemonic
	// used for key derivation. This will bring up Carol with an empty
	// wallet, and such that she is synced up.
	password := []byte("The Magic Words are Squeamish Ossifrage")
	carol, mnemonic, _, err := net.NewNodeWithSeed(
		"Carol", nil, password, false,
	)
	if err != nil {
		t.Fatalf("unable to create node with seed; %v", err)
	}

	shutdownAndAssert(net, t, carol)

	checkInfo := func(expectedRecoveryMode, expectedRecoveryFinished bool,
		expectedProgress float64, recoveryWindow int32) {

		// Restore Carol, passing in the password, mnemonic, and
		// desired recovery window.
		node, err := net.RestoreNodeWithSeed(
			"Carol", nil, password, mnemonic, recoveryWindow, nil,
		)
		if err != nil {
			t.Fatalf("unable to restore node: %v", err)
		}

		// Wait for Carol to sync to the chain.
		_, minerHeight, err := net.Miner.Client.GetBestBlock()
		if err != nil {
			t.Fatalf("unable to get current blockheight %v", err)
		}
		ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
		err = waitForNodeBlockHeight(ctxt, node, minerHeight)
		if err != nil {
			t.Fatalf("unable to sync to chain: %v", err)
		}

		// Query carol for her current wallet recovery progress.
		var (
			recoveryMode     bool
			recoveryFinished bool
			progress         float64
		)

		err = wait.Predicate(func() bool {
			// Verify that recovery info gives the right response.
			req := &lnrpc.GetRecoveryInfoRequest{}
			ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
			resp, err := node.GetRecoveryInfo(ctxt, req)
			if err != nil {
				t.Fatalf("unable to query recovery info: %v", err)
			}

			recoveryMode = resp.RecoveryMode
			recoveryFinished = resp.RecoveryFinished
			progress = resp.Progress

			if recoveryMode != expectedRecoveryMode ||
				recoveryFinished != expectedRecoveryFinished ||
				progress != expectedProgress {
				return false
			}

			return true
		}, defaultTimeout)
		if err != nil {
			t.Fatalf("expected recovery mode to be %v, got %v, "+
				"expected recovery finished to be %v, got %v, "+
				"expected progress %v, got %v",
				expectedRecoveryMode, recoveryMode,
				expectedRecoveryFinished, recoveryFinished,
				expectedProgress, progress,
			)
		}

		// Lastly, shutdown this Carol so we can move on to the next
		// restoration.
		shutdownAndAssert(net, t, node)
	}

	// Restore Carol with a recovery window of 0. Since it's not in recovery
	// mode, the recovery info will give a response with recoveryMode=false,
	// recoveryFinished=false, and progress=0
	checkInfo(false, false, 0, 0)

	// Change the recovery windown to be 1 to turn on recovery mode. Since the
	// current chain height is the same as the birthday height, it should
	// indicate the recovery process is finished.
	checkInfo(true, true, 1, 1)

	// We now go ahead 5 blocks. Because the wallet's syncing process is
	// controlled by a goroutine in the background, it will catch up quickly.
	// This makes the recovery progress back to 1.
	mineBlocks(t, net, 5, 0)
	checkInfo(true, true, 1, 1)
}

// testOnchainFundRecovery checks lnd's ability to rescan for onchain outputs
// when providing a valid aezeed that owns outputs on the chain. This test
// performs multiple restorations using the same seed and various recovery
// windows to ensure we detect funds properly.
func testOnchainFundRecovery(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// First, create a new node with strong passphrase and grab the mnemonic
	// used for key derivation. This will bring up Carol with an empty
	// wallet, and such that she is synced up.
	password := []byte("The Magic Words are Squeamish Ossifrage")
	carol, mnemonic, _, err := net.NewNodeWithSeed(
		"Carol", nil, password, false,
	)
	if err != nil {
		t.Fatalf("unable to create node with seed; %v", err)
	}
	shutdownAndAssert(net, t, carol)

	// Create a closure for testing the recovery of Carol's wallet. This
	// method takes the expected value of Carol's balance when using the
	// given recovery window. Additionally, the caller can specify an action
	// to perform on the restored node before the node is shutdown.
	restoreCheckBalance := func(expAmount int64, expectedNumUTXOs uint32,
		recoveryWindow int32, fn func(*lntest.HarnessNode)) {

		// Restore Carol, passing in the password, mnemonic, and
		// desired recovery window.
		node, err := net.RestoreNodeWithSeed(
			"Carol", nil, password, mnemonic, recoveryWindow, nil,
		)
		if err != nil {
			t.Fatalf("unable to restore node: %v", err)
		}

		// Query carol for her current wallet balance, and also that we
		// gain the expected number of UTXOs.
		var (
			currBalance  int64
			currNumUTXOs uint32
		)
		err = wait.Predicate(func() bool {
			req := &lnrpc.WalletBalanceRequest{}
			ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
			resp, err := node.WalletBalance(ctxt, req)
			if err != nil {
				t.Fatalf("unable to query wallet balance: %v",
					err)
			}
			currBalance = resp.ConfirmedBalance

			utxoReq := &lnrpc.ListUnspentRequest{
				MaxConfs: math.MaxInt32,
			}
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			utxoResp, err := node.ListUnspent(ctxt, utxoReq)
			if err != nil {
				t.Fatalf("unable to query utxos: %v", err)
			}
			currNumUTXOs = uint32(len(utxoResp.Utxos))

			// Verify that Carol's balance and number of UTXOs
			// matches what's expected.
			if expAmount != currBalance {
				return false
			}
			if currNumUTXOs != expectedNumUTXOs {
				return false
			}

			return true
		}, defaultTimeout)
		if err != nil {
			t.Fatalf("expected restored node to have %d satoshis, "+
				"instead has %d satoshis, expected %d utxos "+
				"instead has %d", expAmount, currBalance,
				expectedNumUTXOs, currNumUTXOs)
		}

		// If the user provided a callback, execute the commands against
		// the restored Carol.
		if fn != nil {
			fn(node)
		}

		// Lastly, shutdown this Carol so we can move on to the next
		// restoration.
		shutdownAndAssert(net, t, node)
	}

	// Create a closure-factory for building closures that can generate and
	// skip a configurable number of addresses, before finally sending coins
	// to a next generated address. The returned closure will apply the same
	// behavior to both default P2WKH and NP2WKH scopes.
	skipAndSend := func(nskip int) func(*lntest.HarnessNode) {
		return func(node *lntest.HarnessNode) {
			newP2WKHAddrReq := &lnrpc.NewAddressRequest{
				Type: AddrTypeWitnessPubkeyHash,
			}

			newNP2WKHAddrReq := &lnrpc.NewAddressRequest{
				Type: AddrTypeNestedPubkeyHash,
			}

			// Generate and skip the number of addresses requested.
			for i := 0; i < nskip; i++ {
				ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
				_, err = node.NewAddress(ctxt, newP2WKHAddrReq)
				if err != nil {
					t.Fatalf("unable to generate new "+
						"p2wkh address: %v", err)
				}

				ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
				_, err = node.NewAddress(ctxt, newNP2WKHAddrReq)
				if err != nil {
					t.Fatalf("unable to generate new "+
						"np2wkh address: %v", err)
				}
			}

			// Send one BTC to the next P2WKH address.
			ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
			net.SendCoins(
				ctxt, t.t, btcutil.SatoshiPerBitcoin, node,
			)

			// And another to the next NP2WKH address.
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			net.SendCoinsNP2WKH(
				ctxt, t.t, btcutil.SatoshiPerBitcoin, node,
			)
		}
	}

	// Restore Carol with a recovery window of 0. Since no coins have been
	// sent, her balance should be zero.
	//
	// After, one BTC is sent to both her first external P2WKH and NP2WKH
	// addresses.
	restoreCheckBalance(0, 0, 0, skipAndSend(0))

	// Check that restoring without a look-ahead results in having no funds
	// in the wallet, even though they exist on-chain.
	restoreCheckBalance(0, 0, 0, nil)

	// Now, check that using a look-ahead of 1 recovers the balance from
	// the two transactions above. We should also now have 2 UTXOs in the
	// wallet at the end of the recovery attempt.
	//
	// After, we will generate and skip 9 P2WKH and NP2WKH addresses, and
	// send another BTC to the subsequent 10th address in each derivation
	// path.
	restoreCheckBalance(2*btcutil.SatoshiPerBitcoin, 2, 1, skipAndSend(9))

	// Check that using a recovery window of 9 does not find the two most
	// recent txns.
	restoreCheckBalance(2*btcutil.SatoshiPerBitcoin, 2, 9, nil)

	// Extending our recovery window to 10 should find the most recent
	// transactions, leaving the wallet with 4 BTC total. We should also
	// learn of the two additional UTXOs created above.
	//
	// After, we will skip 19 more addrs, sending to the 20th address past
	// our last found address, and repeat the same checks.
	restoreCheckBalance(4*btcutil.SatoshiPerBitcoin, 4, 10, skipAndSend(19))

	// Check that recovering with a recovery window of 19 fails to find the
	// most recent transactions.
	restoreCheckBalance(4*btcutil.SatoshiPerBitcoin, 4, 19, nil)

	// Ensure that using a recovery window of 20 succeeds with all UTXOs
	// found and the final balance reflected.

	// After these checks are done, we'll want to make sure we can also
	// recover change address outputs.  This is mainly motivated by a now
	// fixed bug in the wallet in which change addresses could at times be
	// created outside of the default key scopes. Recovery only used to be
	// performed on the default key scopes, so ideally this test case
	// would've caught the bug earlier. Carol has received 6 BTC so far from
	// the miner, we'll send 5 back to ensure all of her UTXOs get spent to
	// avoid fee discrepancies and a change output is formed.
	const minerAmt = 5 * btcutil.SatoshiPerBitcoin
	const finalBalance = 6 * btcutil.SatoshiPerBitcoin
	promptChangeAddr := func(node *lntest.HarnessNode) {
		minerAddr, err := net.Miner.NewAddress()
		if err != nil {
			t.Fatalf("unable to create new miner address: %v", err)
		}
		ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
		resp, err := node.SendCoins(ctxt, &lnrpc.SendCoinsRequest{
			Addr:   minerAddr.String(),
			Amount: minerAmt,
		})
		if err != nil {
			t.Fatalf("unable to send coins to miner: %v", err)
		}
		txid, err := waitForTxInMempool(
			net.Miner.Client, minerMempoolTimeout,
		)
		if err != nil {
			t.Fatalf("transaction not found in mempool: %v", err)
		}
		if resp.Txid != txid.String() {
			t.Fatalf("txid mismatch: %v vs %v", resp.Txid,
				txid.String())
		}
		block := mineBlocks(t, net, 1, 1)[0]
		assertTxInBlock(t, block, txid)
	}
	restoreCheckBalance(finalBalance, 6, 20, promptChangeAddr)

	// We should expect a static fee of 27750 satoshis for spending 6 inputs
	// (3 P2WPKH, 3 NP2WPKH) to two P2WPKH outputs. Carol should therefore
	// only have one UTXO present (the change output) of 6 - 5 - fee BTC.
	const fee = 27750
	restoreCheckBalance(finalBalance-minerAmt-fee, 1, 21, nil)
}

// commitType is a simple enum used to run though the basic funding flow with
// different commitment formats.
type commitType byte

const (
	// commitTypeLegacy is the old school commitment type.
	commitTypeLegacy commitType = iota

	// commiTypeTweakless is the commitment type where the remote key is
	// static (non-tweaked).
	commitTypeTweakless

	// commitTypeAnchors is the kind of commitment that has extra outputs
	// used for anchoring down to commitment using CPFP.
	commitTypeAnchors
)

// String returns that name of the commitment type.
func (c commitType) String() string {
	switch c {
	case commitTypeLegacy:
		return "legacy"
	case commitTypeTweakless:
		return "tweakless"
	case commitTypeAnchors:
		return "anchors"
	default:
		return "invalid"
	}
}

// Args returns the command line flag to supply to enable this commitment type.
func (c commitType) Args() []string {
	switch c {
	case commitTypeLegacy:
		return []string{"--protocol.legacy.committweak"}
	case commitTypeTweakless:
		return []string{}
	case commitTypeAnchors:
		return []string{"--protocol.anchors"}
	}

	return nil
}

// calcStaticFee calculates appropriate fees for commitment transactions.  This
// function provides a simple way to allow test balance assertions to take fee
// calculations into account.
func (c commitType) calcStaticFee(numHTLCs int) btcutil.Amount {
	const htlcWeight = input.HTLCWeight
	var (
		feePerKw     = chainfee.SatPerKVByte(50000).FeePerKWeight()
		commitWeight = input.CommitWeight
		anchors      = btcutil.Amount(0)
	)

	// The anchor commitment type is slightly heavier, and we must also add
	// the value of the two anchors to the resulting fee the initiator
	// pays. In addition the fee rate is capped at 10 sat/vbyte for anchor
	// channels.
	if c == commitTypeAnchors {
		feePerKw = chainfee.SatPerKVByte(
			lnwallet.DefaultAnchorsCommitMaxFeeRateSatPerVByte * 1000,
		).FeePerKWeight()
		commitWeight = input.AnchorCommitWeight
		anchors = 2 * anchorSize
	}

	return feePerKw.FeeForWeight(int64(commitWeight+htlcWeight*numHTLCs)) +
		anchors
}

// channelCommitType retrieves the active channel commitment type for the given
// chan point.
func channelCommitType(node *lntest.HarnessNode,
	chanPoint *lnrpc.ChannelPoint) (commitType, error) {

	ctxb := context.Background()
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)

	req := &lnrpc.ListChannelsRequest{}
	channels, err := node.ListChannels(ctxt, req)
	if err != nil {
		return 0, fmt.Errorf("listchannels failed: %v", err)
	}

	for _, c := range channels.Channels {
		if c.ChannelPoint == txStr(chanPoint) {
			switch c.CommitmentType {

			// If the anchor output size is non-zero, we are
			// dealing with the anchor type.
			case lnrpc.CommitmentType_ANCHORS:
				return commitTypeAnchors, nil

			// StaticRemoteKey means it is tweakless,
			case lnrpc.CommitmentType_STATIC_REMOTE_KEY:
				return commitTypeTweakless, nil

			// Otherwise legacy.
			default:
				return commitTypeLegacy, nil
			}
		}
	}

	return 0, fmt.Errorf("channel point %v not found", chanPoint)
}

// calculateMaxHtlc re-implements the RequiredRemoteChannelReserve of the
// funding manager's config, which corresponds to the maximum MaxHTLC value we
// allow users to set when updating a channel policy.
func calculateMaxHtlc(chanCap btcutil.Amount) uint64 {
	reserve := lnwire.NewMSatFromSatoshis(chanCap / 100)
	max := lnwire.NewMSatFromSatoshis(chanCap) - reserve
	return uint64(max)
}

// waitForNodeBlockHeight queries the node for its current block height until
// it reaches the passed height.
func waitForNodeBlockHeight(ctx context.Context, node *lntest.HarnessNode,
	height int32) error {
	var predErr error
	err := wait.Predicate(func() bool {
		ctxt, _ := context.WithTimeout(ctx, defaultTimeout)
		info, err := node.GetInfo(ctxt, &lnrpc.GetInfoRequest{})
		if err != nil {
			predErr = err
			return false
		}

		if int32(info.BlockHeight) != height {
			predErr = fmt.Errorf("expected block height to "+
				"be %v, was %v", height, info.BlockHeight)
			return false
		}
		return true
	}, defaultTimeout)
	if err != nil {
		return predErr
	}
	return nil
}

// testDisconnectingTargetPeer performs a test which disconnects Alice-peer from
// Bob-peer and then re-connects them again. We expect Alice to be able to
// disconnect at any point.
func testDisconnectingTargetPeer(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// We'll start both nodes with a high backoff so that they don't
	// reconnect automatically during our test.
	args := []string{
		"--minbackoff=1m",
		"--maxbackoff=1m",
	}

	alice := net.NewNode(t.t, "Alice", args)
	defer shutdownAndAssert(net, t, alice)

	bob := net.NewNode(t.t, "Bob", args)
	defer shutdownAndAssert(net, t, bob)

	// Start by connecting Alice and Bob with no channels.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, alice, bob)

	// Check existing connection.
	assertNumConnections(t, alice, bob, 1)

	// Give Alice some coins so she can fund a channel.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, alice)

	chanAmt := funding.MaxBtcFundingAmount
	pushAmt := btcutil.Amount(0)

	// Create a new channel that requires 1 confs before it's considered
	// open, then broadcast the funding transaction
	const numConfs = 1
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	pendingUpdate, err := net.OpenPendingChannel(
		ctxt, alice, bob, chanAmt, pushAmt,
	)
	if err != nil {
		t.Fatalf("unable to open channel: %v", err)
	}

	// At this point, the channel's funding transaction will have been
	// broadcast, but not confirmed. Alice and Bob's nodes should reflect
	// this when queried via RPC.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	assertNumOpenChannelsPending(ctxt, t, alice, bob, 1)

	// Disconnect Alice-peer from Bob-peer and get error causes by one
	// pending channel with detach node is existing.
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("Bob's peer was disconnected from Alice's"+
			" while one pending channel is existing: err %v", err)
	}

	time.Sleep(time.Millisecond * 300)

	// Assert that the connection was torn down.
	assertNumConnections(t, alice, bob, 0)

	fundingTxID, err := chainhash.NewHash(pendingUpdate.Txid)
	if err != nil {
		t.Fatalf("unable to convert funding txid into chainhash.Hash:"+
			" %v", err)
	}

	// Mine a block, then wait for Alice's node to notify us that the
	// channel has been opened. The funding transaction should be found
	// within the newly mined block.
	block := mineBlocks(t, net, numConfs, 1)[0]
	assertTxInBlock(t, block, fundingTxID)

	// At this point, the channel should be fully opened and there should be
	// no pending channels remaining for either node.
	time.Sleep(time.Millisecond * 300)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)

	assertNumOpenChannelsPending(ctxt, t, alice, bob, 0)

	// Reconnect the nodes so that the channel can become active.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, alice, bob)

	// The channel should be listed in the peer information returned by both
	// peers.
	outPoint := wire.OutPoint{
		Hash:  *fundingTxID,
		Index: pendingUpdate.OutputIndex,
	}

	// Check both nodes to ensure that the channel is ready for operation.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.AssertChannelExists(ctxt, alice, &outPoint); err != nil {
		t.Fatalf("unable to assert channel existence: %v", err)
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.AssertChannelExists(ctxt, bob, &outPoint); err != nil {
		t.Fatalf("unable to assert channel existence: %v", err)
	}

	// Disconnect Alice-peer from Bob-peer and get error causes by one
	// active channel with detach node is existing.
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("Bob's peer was disconnected from Alice's"+
			" while one active channel is existing: err %v", err)
	}

	// Check existing connection.
	assertNumConnections(t, alice, bob, 0)

	// Reconnect both nodes before force closing the channel.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, alice, bob)

	// Finally, immediately close the channel. This function will also block
	// until the channel is closed and will additionally assert the relevant
	// channel closing post conditions.
	chanPoint := &lnrpc.ChannelPoint{
		FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
			FundingTxidBytes: pendingUpdate.Txid,
		},
		OutputIndex: pendingUpdate.OutputIndex,
	}

	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, alice, chanPoint, true)

	// Disconnect Alice-peer from Bob-peer without getting error about
	// existing channels.
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("unable to disconnect Bob's peer from Alice's: err %v",
			err)
	}

	// Check zero peer connections.
	assertNumConnections(t, alice, bob, 0)

	// Finally, re-connect both nodes.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, alice, bob)

	// Check existing connection.
	assertNumConnections(t, alice, net.Bob, 1)

	// Cleanup by mining the force close and sweep transaction.
	cleanupForceClose(t, net, alice, chanPoint)
}

// findTxAtHeight gets all of the transactions that a node's wallet has a record
// of at the target height, and finds and returns the tx with the target txid,
// failing if it is not found.
func findTxAtHeight(ctx context.Context, t *harnessTest, height int32,
	target string, node *lntest.HarnessNode) *lnrpc.Transaction {

	txns, err := node.LightningClient.GetTransactions(
		ctx, &lnrpc.GetTransactionsRequest{
			StartHeight: height,
			EndHeight:   height,
		},
	)
	require.NoError(t.t, err, "could not get transactions")

	for _, tx := range txns.Transactions {
		if tx.TxHash == target {
			return tx
		}
	}

	return nil
}

// testChannelBalance creates a new channel between Alice and Bob, then checks
// channel balance to be equal amount specified while creation of channel.
func testChannelBalance(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// Open a channel with 0.16 BTC between Alice and Bob, ensuring the
	// channel has been opened properly.
	amount := funding.MaxBtcFundingAmount

	// Creates a helper closure to be used below which asserts the proper
	// response to a channel balance RPC.
	checkChannelBalance := func(node *lntest.HarnessNode,
		local, remote btcutil.Amount) {

		expectedResponse := &lnrpc.ChannelBalanceResponse{
			LocalBalance: &lnrpc.Amount{
				Sat:  uint64(local),
				Msat: uint64(lnwire.NewMSatFromSatoshis(local)),
			},
			RemoteBalance: &lnrpc.Amount{
				Sat: uint64(remote),
				Msat: uint64(lnwire.NewMSatFromSatoshis(
					remote,
				)),
			},
			UnsettledLocalBalance:    &lnrpc.Amount{},
			UnsettledRemoteBalance:   &lnrpc.Amount{},
			PendingOpenLocalBalance:  &lnrpc.Amount{},
			PendingOpenRemoteBalance: &lnrpc.Amount{},
			// Deprecated fields.
			Balance: int64(local),
		}
		assertChannelBalanceResp(t, node, expectedResponse)
	}

	// Before beginning, make sure alice and bob are connected.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, net.Alice, net.Bob)

	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, net.Alice, net.Bob,
		lntest.OpenChannelParams{
			Amt: amount,
		},
	)

	// Wait for both Alice and Bob to recognize this new channel.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err := net.Alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("alice didn't advertise channel before "+
			"timeout: %v", err)
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = net.Bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("bob didn't advertise channel before "+
			"timeout: %v", err)
	}

	cType, err := channelCommitType(net.Alice, chanPoint)
	if err != nil {
		t.Fatalf("unable to get channel type: %v", err)
	}

	// As this is a single funder channel, Alice's balance should be
	// exactly 0.5 BTC since now state transitions have taken place yet.
	checkChannelBalance(net.Alice, amount-cType.calcStaticFee(0), 0)

	// Ensure Bob currently has no available balance within the channel.
	checkChannelBalance(net.Bob, 0, amount-cType.calcStaticFee(0))

	// Finally close the channel between Alice and Bob, asserting that the
	// channel has been properly closed on-chain.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, chanPoint, false)
}

// testChannelUnsettledBalance will test that the UnsettledBalance field
// is updated according to the number of Pending Htlcs.
// Alice will send Htlcs to Carol while she is in hodl mode. This will result
// in a build of pending Htlcs. We expect the channels unsettled balance to
// equal the sum of all the Pending Htlcs.
func testChannelUnsettledBalance(net *lntest.NetworkHarness, t *harnessTest) {
	const chanAmt = btcutil.Amount(1000000)
	ctxb := context.Background()

	// Creates a helper closure to be used below which asserts the proper
	// response to a channel balance RPC.
	checkChannelBalance := func(node *lntest.HarnessNode,
		local, remote, unsettledLocal, unsettledRemote btcutil.Amount) {

		expectedResponse := &lnrpc.ChannelBalanceResponse{
			LocalBalance: &lnrpc.Amount{
				Sat: uint64(local),
				Msat: uint64(lnwire.NewMSatFromSatoshis(
					local,
				)),
			},
			RemoteBalance: &lnrpc.Amount{
				Sat: uint64(remote),
				Msat: uint64(lnwire.NewMSatFromSatoshis(
					remote,
				)),
			},
			UnsettledLocalBalance: &lnrpc.Amount{
				Sat: uint64(unsettledLocal),
				Msat: uint64(lnwire.NewMSatFromSatoshis(
					unsettledLocal,
				)),
			},
			UnsettledRemoteBalance: &lnrpc.Amount{
				Sat: uint64(unsettledRemote),
				Msat: uint64(lnwire.NewMSatFromSatoshis(
					unsettledRemote,
				)),
			},
			PendingOpenLocalBalance:  &lnrpc.Amount{},
			PendingOpenRemoteBalance: &lnrpc.Amount{},
			// Deprecated fields.
			Balance: int64(local),
		}
		assertChannelBalanceResp(t, node, expectedResponse)
	}

	// Create carol in hodl mode.
	carol := net.NewNode(t.t, "Carol", []string{"--hodl.exit-settle"})
	defer shutdownAndAssert(net, t, carol)

	// Connect Alice to Carol.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxb, t.t, net.Alice, carol)

	// Open a channel between Alice and Carol.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointAlice := openChannelAndAssert(
		ctxt, t, net, net.Alice, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Wait for Alice and Carol to receive the channel edge from the
	// funding manager.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err := net.Alice.WaitForNetworkChannelOpen(ctxt, chanPointAlice)
	if err != nil {
		t.Fatalf("alice didn't see the alice->carol channel before "+
			"timeout: %v", err)
	}

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = carol.WaitForNetworkChannelOpen(ctxt, chanPointAlice)
	if err != nil {
		t.Fatalf("alice didn't see the alice->carol channel before "+
			"timeout: %v", err)
	}

	cType, err := channelCommitType(net.Alice, chanPointAlice)
	require.NoError(t.t, err, "unable to get channel type")

	// Check alice's channel balance, which should have zero remote and zero
	// pending balance.
	checkChannelBalance(net.Alice, chanAmt-cType.calcStaticFee(0), 0, 0, 0)

	// Check carol's channel balance, which should have zero local and zero
	// pending balance.
	checkChannelBalance(carol, 0, chanAmt-cType.calcStaticFee(0), 0, 0)

	// Channel should be ready for payments.
	const (
		payAmt      = 100
		numInvoices = 6
	)

	// Simulateneously send numInvoices payments from Alice to Carol.
	carolPubKey := carol.PubKey[:]
	errChan := make(chan error)
	for i := 0; i < numInvoices; i++ {
		go func() {
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			_, err := net.Alice.RouterClient.SendPaymentV2(ctxt,
				&routerrpc.SendPaymentRequest{
					Dest:           carolPubKey,
					Amt:            int64(payAmt),
					PaymentHash:    makeFakePayHash(t),
					FinalCltvDelta: chainreg.DefaultBitcoinTimeLockDelta,
					TimeoutSeconds: 60,
					FeeLimitMsat:   noFeeLimitMsat,
				})

			if err != nil {
				errChan <- err
			}
		}()
	}

	// Test that the UnsettledBalance for both Alice and Carol
	// is equal to the amount of invoices * payAmt.
	var unsettledErr error
	nodes := []*lntest.HarnessNode{net.Alice, carol}
	err = wait.Predicate(func() bool {
		// There should be a number of PendingHtlcs equal
		// to the amount of Invoices sent.
		unsettledErr = assertNumActiveHtlcs(nodes, numInvoices)
		if unsettledErr != nil {
			return false
		}

		// Set the amount expected for the Unsettled Balance for
		// this channel.
		expectedBalance := numInvoices * payAmt

		// Check each nodes UnsettledBalance field.
		for _, node := range nodes {
			// Get channel info for the node.
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			chanInfo, err := getChanInfo(ctxt, node)
			if err != nil {
				unsettledErr = err
				return false
			}

			// Check that UnsettledBalance is what we expect.
			if int(chanInfo.UnsettledBalance) != expectedBalance {
				unsettledErr = fmt.Errorf("unsettled balance failed "+
					"expected: %v, received: %v", expectedBalance,
					chanInfo.UnsettledBalance)
				return false
			}
		}

		return true
	}, defaultTimeout)
	if err != nil {
		t.Fatalf("unsettled balace error: %v", unsettledErr)
	}

	// Check for payment errors.
	select {
	case err := <-errChan:
		t.Fatalf("payment error: %v", err)
	default:
	}

	// Check alice's channel balance, which should have a remote unsettled
	// balance that equals to the amount of invoices * payAmt. The remote
	// balance remains zero.
	aliceLocal := chanAmt - cType.calcStaticFee(0) - numInvoices*payAmt
	checkChannelBalance(net.Alice, aliceLocal, 0, 0, numInvoices*payAmt)

	// Check carol's channel balance, which should have a local unsettled
	// balance that equals to the amount of invoices * payAmt. The local
	// balance remains zero.
	checkChannelBalance(carol, 0, aliceLocal, numInvoices*payAmt, 0)

	// Force and assert the channel closure.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, chanPointAlice, true)

	// Cleanup by mining the force close and sweep transaction.
	cleanupForceClose(t, net, net.Alice, chanPointAlice)
}

// testSphinxReplayPersistence verifies that replayed onion packets are rejected
// by a remote peer after a restart. We use a combination of unsafe
// configuration arguments to force Carol to replay the same sphinx packet after
// reconnecting to Dave, and compare the returned failure message with what we
// expect for replayed onion packets.
func testSphinxReplayPersistence(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// Open a channel with 100k satoshis between Carol and Dave with Carol being
	// the sole funder of the channel.
	chanAmt := btcutil.Amount(100000)

	// First, we'll create Dave, the receiver, and start him in hodl mode.
	dave := net.NewNode(t.t, "Dave", []string{"--hodl.exit-settle"})

	// We must remember to shutdown the nodes we created for the duration
	// of the tests, only leaving the two seed nodes (Alice and Bob) within
	// our test network.
	defer shutdownAndAssert(net, t, dave)

	// Next, we'll create Carol and establish a channel to from her to
	// Dave. Carol is started in both unsafe-replay which will cause her to
	// replay any pending Adds held in memory upon reconnection.
	carol := net.NewNode(t.t, "Carol", []string{"--unsafe-replay"})
	defer shutdownAndAssert(net, t, carol)

	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, carol, dave)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, carol)

	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, carol, dave,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Next, we'll create Fred who is going to initiate the payment and
	// establish a channel to from him to Carol. We can't perform this test
	// by paying from Carol directly to Dave, because the '--unsafe-replay'
	// setup doesn't apply to locally added htlcs. In that case, the
	// mailbox, that is responsible for generating the replay, is bypassed.
	fred := net.NewNode(t.t, "Fred", nil)
	defer shutdownAndAssert(net, t, fred)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, fred, carol)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, fred)

	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointFC := openChannelAndAssert(
		ctxt, t, net, fred, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Now that the channel is open, create an invoice for Dave which
	// expects a payment of 1000 satoshis from Carol paid via a particular
	// preimage.
	const paymentAmt = 1000
	preimage := bytes.Repeat([]byte("A"), 32)
	invoice := &lnrpc.Invoice{
		Memo:      "testing",
		RPreimage: preimage,
		Value:     paymentAmt,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	invoiceResp, err := dave.AddInvoice(ctxt, invoice)
	if err != nil {
		t.Fatalf("unable to add invoice: %v", err)
	}

	// Wait for all channels to be recognized and advertized.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = carol.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("alice didn't advertise channel before "+
			"timeout: %v", err)
	}
	err = dave.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("bob didn't advertise channel before "+
			"timeout: %v", err)
	}
	err = carol.WaitForNetworkChannelOpen(ctxt, chanPointFC)
	if err != nil {
		t.Fatalf("alice didn't advertise channel before "+
			"timeout: %v", err)
	}
	err = fred.WaitForNetworkChannelOpen(ctxt, chanPointFC)
	if err != nil {
		t.Fatalf("bob didn't advertise channel before "+
			"timeout: %v", err)
	}

	// With the invoice for Dave added, send a payment from Fred paying
	// to the above generated invoice.
	ctx, cancel := context.WithCancel(ctxb)
	defer cancel()

	payStream, err := fred.RouterClient.SendPaymentV2(
		ctx,
		&routerrpc.SendPaymentRequest{
			PaymentRequest: invoiceResp.PaymentRequest,
			TimeoutSeconds: 60,
			FeeLimitMsat:   noFeeLimitMsat,
		},
	)
	if err != nil {
		t.Fatalf("unable to open payment stream: %v", err)
	}

	time.Sleep(200 * time.Millisecond)

	// Dave's invoice should not be marked as settled.
	payHash := &lnrpc.PaymentHash{
		RHash: invoiceResp.RHash,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	dbInvoice, err := dave.LookupInvoice(ctxt, payHash)
	if err != nil {
		t.Fatalf("unable to lookup invoice: %v", err)
	}
	if dbInvoice.Settled {
		t.Fatalf("dave's invoice should not be marked as settled: %v",
			spew.Sdump(dbInvoice))
	}

	// With the payment sent but hedl, all balance related stats should not
	// have changed.
	err = wait.InvariantNoError(
		assertAmountSent(0, carol, dave), 3*time.Second,
	)
	if err != nil {
		t.Fatalf(err.Error())
	}

	// With the first payment sent, restart dave to make sure he is
	// persisting the information required to detect replayed sphinx
	// packets.
	if err := net.RestartNode(dave, nil); err != nil {
		t.Fatalf("unable to restart dave: %v", err)
	}

	// Carol should retransmit the Add hedl in her mailbox on startup. Dave
	// should not accept the replayed Add, and actually fail back the
	// pending payment. Even though he still holds the original settle, if
	// he does fail, it is almost certainly caused by the sphinx replay
	// protection, as it is the only validation we do in hodl mode.
	result, err := getPaymentResult(payStream)
	if err != nil {
		t.Fatalf("unable to receive payment response: %v", err)
	}

	// Assert that Fred receives the expected failure after Carol sent a
	// duplicate packet that fails due to sphinx replay detection.
	if result.Status == lnrpc.Payment_SUCCEEDED {
		t.Fatalf("expected payment error")
	}
	assertLastHTLCError(t, fred, lnrpc.Failure_INVALID_ONION_KEY)

	// Since the payment failed, the balance should still be left
	// unaltered.
	err = wait.InvariantNoError(
		assertAmountSent(0, carol, dave), 3*time.Second,
	)
	if err != nil {
		t.Fatalf(err.Error())
	}

	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, carol, chanPoint, true)

	// Cleanup by mining the force close and sweep transaction.
	cleanupForceClose(t, net, carol, chanPoint)
}

// testListChannels checks that the response from ListChannels is correct. It
// tests the values in all ChannelConstraints are returned as expected. Once
// ListChannels becomes mature, a test against all fields in ListChannels should
// be performed.
func testListChannels(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	const aliceRemoteMaxHtlcs = 50
	const bobRemoteMaxHtlcs = 100

	// Create two fresh nodes and open a channel between them.
	alice := net.NewNode(t.t, "Alice", nil)
	defer shutdownAndAssert(net, t, alice)

	bob := net.NewNode(
		t.t, "Bob", []string{
			fmt.Sprintf(
				"--default-remote-max-htlcs=%v",
				bobRemoteMaxHtlcs,
			),
		},
	)
	defer shutdownAndAssert(net, t, bob)

	// Connect Alice to Bob.
	net.ConnectNodes(ctxb, t.t, alice, bob)

	// Give Alice some coins so she can fund a channel.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, alice)

	// Open a channel with 100k satoshis between Alice and Bob with Alice
	// being the sole funder of the channel. The minial HTLC amount is set to
	// 4200 msats.
	const customizedMinHtlc = 4200

	chanAmt := btcutil.Amount(100000)
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, alice, bob,
		lntest.OpenChannelParams{
			Amt:            chanAmt,
			MinHtlc:        customizedMinHtlc,
			RemoteMaxHtlcs: aliceRemoteMaxHtlcs,
		},
	)

	// Wait for Alice and Bob to receive the channel edge from the
	// funding manager.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err := alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("alice didn't see the alice->bob channel before "+
			"timeout: %v", err)
	}

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("bob didn't see the bob->alice channel before "+
			"timeout: %v", err)
	}

	// Alice should have one channel opened with Bob.
	assertNodeNumChannels(t, alice, 1)
	// Bob should have one channel opened with Alice.
	assertNodeNumChannels(t, bob, 1)

	// Get the ListChannel response from Alice.
	listReq := &lnrpc.ListChannelsRequest{}
	ctxb = context.Background()
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	resp, err := alice.ListChannels(ctxt, listReq)
	if err != nil {
		t.Fatalf("unable to query for %s's channel list: %v",
			alice.Name(), err)
	}

	// Check the returned response is correct.
	aliceChannel := resp.Channels[0]

	// defaultConstraints is a ChannelConstraints with default values. It is
	// used to test against Alice's local channel constraints.
	defaultConstraints := &lnrpc.ChannelConstraints{
		CsvDelay:          4,
		ChanReserveSat:    1000,
		DustLimitSat:      uint64(lnwallet.DefaultDustLimit()),
		MaxPendingAmtMsat: 99000000,
		MinHtlcMsat:       1,
		MaxAcceptedHtlcs:  bobRemoteMaxHtlcs,
	}
	assertChannelConstraintsEqual(
		t, defaultConstraints, aliceChannel.LocalConstraints,
	)

	// customizedConstraints is a ChannelConstraints with customized values.
	// Ideally, all these values can be passed in when creating the channel.
	// Currently, only the MinHtlcMsat is customized. It is used to check
	// against Alice's remote channel constratins.
	customizedConstraints := &lnrpc.ChannelConstraints{
		CsvDelay:          4,
		ChanReserveSat:    1000,
		DustLimitSat:      uint64(lnwallet.DefaultDustLimit()),
		MaxPendingAmtMsat: 99000000,
		MinHtlcMsat:       customizedMinHtlc,
		MaxAcceptedHtlcs:  aliceRemoteMaxHtlcs,
	}
	assertChannelConstraintsEqual(
		t, customizedConstraints, aliceChannel.RemoteConstraints,
	)

	// Get the ListChannel response for Bob.
	listReq = &lnrpc.ListChannelsRequest{}
	ctxb = context.Background()
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	resp, err = bob.ListChannels(ctxt, listReq)
	if err != nil {
		t.Fatalf("unable to query for %s's channel "+
			"list: %v", bob.Name(), err)
	}

	bobChannel := resp.Channels[0]
	if bobChannel.ChannelPoint != aliceChannel.ChannelPoint {
		t.Fatalf("Bob's channel point mismatched, want: %s, got: %s",
			chanPoint.String(), bobChannel.ChannelPoint,
		)
	}

	// Check channel constraints match. Alice's local channel constraint should
	// be equal to Bob's remote channel constraint, and her remote one should
	// be equal to Bob's local one.
	assertChannelConstraintsEqual(
		t, aliceChannel.LocalConstraints, bobChannel.RemoteConstraints,
	)
	assertChannelConstraintsEqual(
		t, aliceChannel.RemoteConstraints, bobChannel.LocalConstraints,
	)

}

// testUpdateChanStatus checks that calls to the UpdateChanStatus RPC update
// the channel graph as expected, and that channel state is properly updated
// in the presence of interleaved node disconnects / reconnects.
func testUpdateChanStatus(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// Create two fresh nodes and open a channel between them.
	alice := net.NewNode(
		t.t, "Alice", []string{
			"--minbackoff=10s",
			"--chan-enable-timeout=1.5s",
			"--chan-disable-timeout=3s",
			"--chan-status-sample-interval=.5s",
		},
	)
	defer shutdownAndAssert(net, t, alice)

	bob := net.NewNode(
		t.t, "Bob", []string{
			"--minbackoff=10s",
			"--chan-enable-timeout=1.5s",
			"--chan-disable-timeout=3s",
			"--chan-status-sample-interval=.5s",
		},
	)
	defer shutdownAndAssert(net, t, bob)

	// Connect Alice to Bob.
	net.ConnectNodes(ctxb, t.t, alice, bob)

	// Give Alice some coins so she can fund a channel.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, alice)

	// Open a channel with 100k satoshis between Alice and Bob with Alice
	// being the sole funder of the channel.
	chanAmt := btcutil.Amount(100000)
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, alice, bob,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Wait for Alice and Bob to receive the channel edge from the
	// funding manager.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err := alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("alice didn't see the alice->bob channel before "+
			"timeout: %v", err)
	}

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("bob didn't see the bob->alice channel before "+
			"timeout: %v", err)
	}

	// Launch a node for Carol which will connect to Alice and Bob in
	// order to receive graph updates. This will ensure that the
	// channel updates are propagated throughout the network.
	carol := net.NewNode(t.t, "Carol", nil)
	defer shutdownAndAssert(net, t, carol)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, alice, carol)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, bob, carol)

	carolSub := subscribeGraphNotifications(ctxb, t, carol)
	defer close(carolSub.quit)

	// sendReq sends an UpdateChanStatus request to the given node.
	sendReq := func(node *lntest.HarnessNode, chanPoint *lnrpc.ChannelPoint,
		action routerrpc.ChanStatusAction) {

		req := &routerrpc.UpdateChanStatusRequest{
			ChanPoint: chanPoint,
			Action:    action,
		}
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		_, err = node.RouterClient.UpdateChanStatus(ctxt, req)
		if err != nil {
			t.Fatalf("unable to call UpdateChanStatus for %s's node: %v",
				node.Name(), err)
		}
	}

	// assertEdgeDisabled ensures that a given node has the correct
	// Disabled state for a channel.
	assertEdgeDisabled := func(node *lntest.HarnessNode,
		chanPoint *lnrpc.ChannelPoint, disabled bool) {

		var predErr error
		err = wait.Predicate(func() bool {
			req := &lnrpc.ChannelGraphRequest{
				IncludeUnannounced: true,
			}
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			chanGraph, err := node.DescribeGraph(ctxt, req)
			if err != nil {
				predErr = fmt.Errorf("unable to query node %v's graph: %v", node, err)
				return false
			}
			numEdges := len(chanGraph.Edges)
			if numEdges != 1 {
				predErr = fmt.Errorf("expected to find 1 edge in the graph, found %d", numEdges)
				return false
			}
			edge := chanGraph.Edges[0]
			if edge.ChanPoint != chanPoint.GetFundingTxidStr() {
				predErr = fmt.Errorf("expected chan_point %v, got %v",
					chanPoint.GetFundingTxidStr(), edge.ChanPoint)
			}
			var policy *lnrpc.RoutingPolicy
			if node.PubKeyStr == edge.Node1Pub {
				policy = edge.Node1Policy
			} else {
				policy = edge.Node2Policy
			}
			if disabled != policy.Disabled {
				predErr = fmt.Errorf("expected policy.Disabled to be %v, "+
					"but policy was %v", disabled, policy)
				return false
			}
			return true
		}, defaultTimeout)
		if err != nil {
			t.Fatalf("%v", predErr)
		}
	}

	// When updating the state of the channel between Alice and Bob, we
	// should expect to see channel updates with the default routing
	// policy. The value of "Disabled" will depend on the specific
	// scenario being tested.
	expectedPolicy := &lnrpc.RoutingPolicy{
		FeeBaseMsat:      int64(chainreg.DefaultBitcoinBaseFeeMSat),
		FeeRateMilliMsat: int64(chainreg.DefaultBitcoinFeeRate),
		TimeLockDelta:    chainreg.DefaultBitcoinTimeLockDelta,
		MinHtlc:          1000, // default value
		MaxHtlcMsat:      calculateMaxHtlc(chanAmt),
	}

	// Initially, the channel between Alice and Bob should not be
	// disabled.
	assertEdgeDisabled(alice, chanPoint, false)

	// Manually disable the channel and ensure that a "Disabled = true"
	// update is propagated.
	sendReq(alice, chanPoint, routerrpc.ChanStatusAction_DISABLE)
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// Re-enable the channel and ensure that a "Disabled = false" update
	// is propagated.
	sendReq(alice, chanPoint, routerrpc.ChanStatusAction_ENABLE)
	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// Manually enabling a channel should NOT prevent subsequent
	// disconnections from automatically disabling the channel again
	// (we don't want to clutter the network with channels that are
	// falsely advertised as enabled when they don't work).
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("unable to disconnect Alice from Bob: %v", err)
	}
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// Reconnecting the nodes should propagate a "Disabled = false" update.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, alice, bob)
	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// Manually disabling the channel should prevent a subsequent
	// disconnect / reconnect from re-enabling the channel on
	// Alice's end. Note the asymmetry between manual enable and
	// manual disable!
	sendReq(alice, chanPoint, routerrpc.ChanStatusAction_DISABLE)

	// Alice sends out the "Disabled = true" update in response to
	// the ChanStatusAction_DISABLE request.
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("unable to disconnect Alice from Bob: %v", err)
	}

	// Bob sends a "Disabled = true" update upon detecting the
	// disconnect.
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// Bob sends a "Disabled = false" update upon detecting the
	// reconnect.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, alice, bob)
	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// However, since we manually disabled the channel on Alice's end,
	// the policy on Alice's end should still be "Disabled = true". Again,
	// note the asymmetry between manual enable and manual disable!
	assertEdgeDisabled(alice, chanPoint, true)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("unable to disconnect Alice from Bob: %v", err)
	}

	// Bob sends a "Disabled = true" update upon detecting the
	// disconnect.
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)

	// After restoring automatic channel state management on Alice's end,
	// BOTH Alice and Bob should set the channel state back to "enabled"
	// on reconnect.
	sendReq(alice, chanPoint, routerrpc.ChanStatusAction_AUTO)
	net.EnsureConnected(ctxt, t.t, alice, bob)
	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, carolSub,
		[]expectedChanUpdate{
			{alice.PubKeyStr, expectedPolicy, chanPoint},
			{bob.PubKeyStr, expectedPolicy, chanPoint},
		},
	)
	assertEdgeDisabled(alice, chanPoint, false)
}

// testUnannouncedChannels checks unannounced channels are not returned by
// describeGraph RPC request unless explicitly asked for.
func testUnannouncedChannels(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	amount := funding.MaxBtcFundingAmount

	// Open a channel between Alice and Bob, ensuring the
	// channel has been opened properly.
	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	chanOpenUpdate := openChannelStream(
		ctxt, t, net, net.Alice, net.Bob,
		lntest.OpenChannelParams{
			Amt: amount,
		},
	)

	// Mine 2 blocks, and check that the channel is opened but not yet
	// announced to the network.
	mineBlocks(t, net, 2, 1)

	// One block is enough to make the channel ready for use, since the
	// nodes have defaultNumConfs=1 set.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	fundingChanPoint, err := net.WaitForChannelOpen(ctxt, chanOpenUpdate)
	if err != nil {
		t.Fatalf("error while waiting for channel open: %v", err)
	}

	// Alice should have 1 edge in her graph.
	req := &lnrpc.ChannelGraphRequest{
		IncludeUnannounced: true,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	chanGraph, err := net.Alice.DescribeGraph(ctxt, req)
	if err != nil {
		t.Fatalf("unable to query alice's graph: %v", err)
	}

	numEdges := len(chanGraph.Edges)
	if numEdges != 1 {
		t.Fatalf("expected to find 1 edge in the graph, found %d", numEdges)
	}

	// Channels should not be announced yet, hence Alice should have no
	// announced edges in her graph.
	req.IncludeUnannounced = false
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	chanGraph, err = net.Alice.DescribeGraph(ctxt, req)
	if err != nil {
		t.Fatalf("unable to query alice's graph: %v", err)
	}

	numEdges = len(chanGraph.Edges)
	if numEdges != 0 {
		t.Fatalf("expected to find 0 announced edges in the graph, found %d",
			numEdges)
	}

	// Mine 4 more blocks, and check that the channel is now announced.
	mineBlocks(t, net, 4, 0)

	// Give the network a chance to learn that auth proof is confirmed.
	var predErr error
	err = wait.Predicate(func() bool {
		// The channel should now be announced. Check that Alice has 1
		// announced edge.
		req.IncludeUnannounced = false
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		chanGraph, err = net.Alice.DescribeGraph(ctxt, req)
		if err != nil {
			predErr = fmt.Errorf("unable to query alice's graph: %v", err)
			return false
		}

		numEdges = len(chanGraph.Edges)
		if numEdges != 1 {
			predErr = fmt.Errorf("expected to find 1 announced edge in "+
				"the graph, found %d", numEdges)
			return false
		}
		return true
	}, defaultTimeout)
	if err != nil {
		t.Fatalf("%v", predErr)
	}

	// The channel should now be announced. Check that Alice has 1 announced
	// edge.
	req.IncludeUnannounced = false
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	chanGraph, err = net.Alice.DescribeGraph(ctxt, req)
	if err != nil {
		t.Fatalf("unable to query alice's graph: %v", err)
	}

	numEdges = len(chanGraph.Edges)
	if numEdges != 1 {
		t.Fatalf("expected to find 1 announced edge in the graph, found %d",
			numEdges)
	}

	// Close the channel used during the test.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, fundingChanPoint, false)
}

// channelSubscription houses the proxied update and error chans for a node's
// channel subscriptions.
type channelSubscription struct {
	updateChan chan *lnrpc.ChannelEventUpdate
	errChan    chan error
	quit       chan struct{}
}

// subscribeChannelNotifications subscribes to channel updates and launches a
// goroutine that forwards these to the returned channel.
func subscribeChannelNotifications(ctxb context.Context, t *harnessTest,
	node *lntest.HarnessNode) channelSubscription {

	// We'll first start by establishing a notification client which will
	// send us notifications upon channels becoming active, inactive or
	// closed.
	req := &lnrpc.ChannelEventSubscription{}
	ctx, cancelFunc := context.WithCancel(ctxb)

	chanUpdateClient, err := node.SubscribeChannelEvents(ctx, req)
	if err != nil {
		t.Fatalf("unable to create channel update client: %v", err)
	}

	// We'll launch a goroutine that will be responsible for proxying all
	// notifications recv'd from the client into the channel below.
	errChan := make(chan error, 1)
	quit := make(chan struct{})
	chanUpdates := make(chan *lnrpc.ChannelEventUpdate, 20)
	go func() {
		defer cancelFunc()
		for {
			select {
			case <-quit:
				return
			default:
				chanUpdate, err := chanUpdateClient.Recv()
				select {
				case <-quit:
					return
				default:
				}

				if err == io.EOF {
					return
				} else if err != nil {
					select {
					case errChan <- err:
					case <-quit:
					}
					return
				}

				select {
				case chanUpdates <- chanUpdate:
				case <-quit:
					return
				}
			}
		}
	}()

	return channelSubscription{
		updateChan: chanUpdates,
		errChan:    errChan,
		quit:       quit,
	}
}

// testMaxPendingChannels checks that error is returned from remote peer if
// max pending channel number was exceeded and that '--maxpendingchannels' flag
// exists and works properly.
func testMaxPendingChannels(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	maxPendingChannels := lncfg.DefaultMaxPendingChannels + 1
	amount := funding.MaxBtcFundingAmount

	// Create a new node (Carol) with greater number of max pending
	// channels.
	args := []string{
		fmt.Sprintf("--maxpendingchannels=%v", maxPendingChannels),
	}
	carol := net.NewNode(t.t, "Carol", args)
	defer shutdownAndAssert(net, t, carol)

	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, net.Alice, carol)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	carolBalance := btcutil.Amount(maxPendingChannels) * amount
	net.SendCoins(ctxt, t.t, carolBalance, carol)

	// Send open channel requests without generating new blocks thereby
	// increasing pool of pending channels. Then check that we can't open
	// the channel if the number of pending channels exceed max value.
	openStreams := make([]lnrpc.Lightning_OpenChannelClient, maxPendingChannels)
	for i := 0; i < maxPendingChannels; i++ {
		ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
		stream := openChannelStream(
			ctxt, t, net, net.Alice, carol,
			lntest.OpenChannelParams{
				Amt: amount,
			},
		)
		openStreams[i] = stream
	}

	// Carol exhausted available amount of pending channels, next open
	// channel request should cause ErrorGeneric to be sent back to Alice.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	_, err := net.OpenChannel(
		ctxt, net.Alice, carol,
		lntest.OpenChannelParams{
			Amt: amount,
		},
	)

	if err == nil {
		t.Fatalf("error wasn't received")
	} else if !strings.Contains(
		err.Error(), lnwire.ErrMaxPendingChannels.Error(),
	) {
		t.Fatalf("not expected error was received: %v", err)
	}

	// For now our channels are in pending state, in order to not interfere
	// with other tests we should clean up - complete opening of the
	// channel and then close it.

	// Mine 6 blocks, then wait for node's to notify us that the channel has
	// been opened. The funding transactions should be found within the
	// first newly mined block. 6 blocks make sure the funding transaction
	// has enough confirmations to be announced publicly.
	block := mineBlocks(t, net, 6, maxPendingChannels)[0]

	chanPoints := make([]*lnrpc.ChannelPoint, maxPendingChannels)
	for i, stream := range openStreams {
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		fundingChanPoint, err := net.WaitForChannelOpen(ctxt, stream)
		if err != nil {
			t.Fatalf("error while waiting for channel open: %v", err)
		}

		fundingTxID, err := lnrpc.GetChanPointFundingTxid(fundingChanPoint)
		if err != nil {
			t.Fatalf("unable to get txid: %v", err)
		}

		// Ensure that the funding transaction enters a block, and is
		// properly advertised by Alice.
		assertTxInBlock(t, block, fundingTxID)
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		err = net.Alice.WaitForNetworkChannelOpen(ctxt, fundingChanPoint)
		if err != nil {
			t.Fatalf("channel not seen on network before "+
				"timeout: %v", err)
		}

		// The channel should be listed in the peer information
		// returned by both peers.
		chanPoint := wire.OutPoint{
			Hash:  *fundingTxID,
			Index: fundingChanPoint.OutputIndex,
		}
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		if err := net.AssertChannelExists(ctxt, net.Alice, &chanPoint); err != nil {
			t.Fatalf("unable to assert channel existence: %v", err)
		}

		chanPoints[i] = fundingChanPoint
	}

	// Next, close the channel between Alice and Carol, asserting that the
	// channel has been properly closed on-chain.
	for _, chanPoint := range chanPoints {
		ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
		closeChannelAndAssert(ctxt, t, net, net.Alice, chanPoint, false)
	}
}

// getNTxsFromMempool polls until finding the desired number of transactions in
// the provided miner's mempool and returns the full transactions to the caller.
func getNTxsFromMempool(miner *rpcclient.Client, n int,
	timeout time.Duration) ([]*wire.MsgTx, error) {

	txids, err := waitForNTxsInMempool(miner, n, timeout)
	if err != nil {
		return nil, err
	}

	var txes []*wire.MsgTx
	for _, txid := range txids {
		tx, err := miner.GetRawTransaction(txid)
		if err != nil {
			return nil, err
		}
		txes = append(txes, tx.MsgTx())
	}
	return txes, nil
}

// getTxFee retrieves parent transactions and reconstructs the fee paid.
func getTxFee(miner *rpcclient.Client, tx *wire.MsgTx) (btcutil.Amount, error) {
	var balance btcutil.Amount
	for _, in := range tx.TxIn {
		parentHash := in.PreviousOutPoint.Hash
		rawTx, err := miner.GetRawTransaction(&parentHash)
		if err != nil {
			return 0, err
		}
		parent := rawTx.MsgTx()
		balance += btcutil.Amount(
			parent.TxOut[in.PreviousOutPoint.Index].Value,
		)
	}

	for _, out := range tx.TxOut {
		balance -= btcutil.Amount(out.Value)
	}

	return balance, nil
}

// testGarbageCollectLinkNodes tests that we properly garbase collect link nodes
// from the database and the set of persistent connections within the server.
func testGarbageCollectLinkNodes(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	const (
		chanAmt = 1000000
	)

	// Open a channel between Alice and Bob which will later be
	// cooperatively closed.
	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	coopChanPoint := openChannelAndAssert(
		ctxt, t, net, net.Alice, net.Bob,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Create Carol's node and connect Alice to her.
	carol := net.NewNode(t.t, "Carol", nil)
	defer shutdownAndAssert(net, t, carol)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, net.Alice, carol)

	// Open a channel between Alice and Carol which will later be force
	// closed.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	forceCloseChanPoint := openChannelAndAssert(
		ctxt, t, net, net.Alice, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Now, create Dave's a node and also open a channel between Alice and
	// him. This link will serve as the only persistent link throughout
	// restarts in this test.
	dave := net.NewNode(t.t, "Dave", nil)
	defer shutdownAndAssert(net, t, dave)

	net.ConnectNodes(ctxt, t.t, net.Alice, dave)
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	persistentChanPoint := openChannelAndAssert(
		ctxt, t, net, net.Alice, dave,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// isConnected is a helper closure that checks if a peer is connected to
	// Alice.
	isConnected := func(pubKey string) bool {
		req := &lnrpc.ListPeersRequest{}
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		resp, err := net.Alice.ListPeers(ctxt, req)
		if err != nil {
			t.Fatalf("unable to retrieve alice's peers: %v", err)
		}

		for _, peer := range resp.Peers {
			if peer.PubKey == pubKey {
				return true
			}
		}

		return false
	}

	// Restart both Bob and Carol to ensure Alice is able to reconnect to
	// them.
	if err := net.RestartNode(net.Bob, nil); err != nil {
		t.Fatalf("unable to restart bob's node: %v", err)
	}
	if err := net.RestartNode(carol, nil); err != nil {
		t.Fatalf("unable to restart carol's node: %v", err)
	}

	require.Eventually(t.t, func() bool {
		return isConnected(net.Bob.PubKeyStr)
	}, defaultTimeout, 20*time.Millisecond)
	require.Eventually(t.t, func() bool {
		return isConnected(carol.PubKeyStr)
	}, defaultTimeout, 20*time.Millisecond)

	// We'll also restart Alice to ensure she can reconnect to her peers
	// with open channels.
	if err := net.RestartNode(net.Alice, nil); err != nil {
		t.Fatalf("unable to restart alice's node: %v", err)
	}

	require.Eventually(t.t, func() bool {
		return isConnected(net.Bob.PubKeyStr)
	}, defaultTimeout, 20*time.Millisecond)
	require.Eventually(t.t, func() bool {
		return isConnected(carol.PubKeyStr)
	}, defaultTimeout, 20*time.Millisecond)
	require.Eventually(t.t, func() bool {
		return isConnected(dave.PubKeyStr)
	}, defaultTimeout, 20*time.Millisecond)
	err := wait.Predicate(func() bool {
		return isConnected(dave.PubKeyStr)
	}, defaultTimeout)

	// testReconnection is a helper closure that restarts the nodes at both
	// ends of a channel to ensure they do not reconnect after restarting.
	// When restarting Alice, we'll first need to ensure she has
	// reestablished her connection with Dave, as they still have an open
	// channel together.
	testReconnection := func(node *lntest.HarnessNode) {
		// Restart both nodes, to trigger the pruning logic.
		if err := net.RestartNode(node, nil); err != nil {
			t.Fatalf("unable to restart %v's node: %v",
				node.Name(), err)
		}

		if err := net.RestartNode(net.Alice, nil); err != nil {
			t.Fatalf("unable to restart alice's node: %v", err)
		}

		// Now restart both nodes and make sure they don't reconnect.
		if err := net.RestartNode(node, nil); err != nil {
			t.Fatalf("unable to restart %v's node: %v", node.Name(),
				err)
		}
		err = wait.Invariant(func() bool {
			return !isConnected(node.PubKeyStr)
		}, 5*time.Second)
		if err != nil {
			t.Fatalf("alice reconnected to %v", node.Name())
		}

		if err := net.RestartNode(net.Alice, nil); err != nil {
			t.Fatalf("unable to restart alice's node: %v", err)
		}
		err = wait.Predicate(func() bool {
			return isConnected(dave.PubKeyStr)
		}, defaultTimeout)
		if err != nil {
			t.Fatalf("alice didn't reconnect to Dave")
		}

		err = wait.Invariant(func() bool {
			return !isConnected(node.PubKeyStr)
		}, 5*time.Second)
		if err != nil {
			t.Fatalf("alice reconnected to %v", node.Name())
		}
	}

	// Now, we'll close the channel between Alice and Bob and ensure there
	// is no reconnection logic between the both once the channel is fully
	// closed.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, coopChanPoint, false)

	testReconnection(net.Bob)

	// We'll do the same with Alice and Carol, but this time we'll force
	// close the channel instead.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, forceCloseChanPoint, true)

	// Cleanup by mining the force close and sweep transaction.
	cleanupForceClose(t, net, net.Alice, forceCloseChanPoint)

	// We'll need to mine some blocks in order to mark the channel fully
	// closed.
	_, err = net.Miner.Client.Generate(chainreg.DefaultBitcoinTimeLockDelta - defaultCSV)
	if err != nil {
		t.Fatalf("unable to generate blocks: %v", err)
	}

	// Before we test reconnection, we'll ensure that the channel has been
	// fully cleaned up for both Carol and Alice.
	var predErr error
	pendingChansRequest := &lnrpc.PendingChannelsRequest{}
	err = wait.Predicate(func() bool {
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		pendingChanResp, err := net.Alice.PendingChannels(
			ctxt, pendingChansRequest,
		)
		if err != nil {
			predErr = fmt.Errorf("unable to query for pending "+
				"channels: %v", err)
			return false
		}

		predErr = checkNumForceClosedChannels(pendingChanResp, 0)
		if predErr != nil {
			return false
		}

		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		pendingChanResp, err = carol.PendingChannels(
			ctxt, pendingChansRequest,
		)
		if err != nil {
			predErr = fmt.Errorf("unable to query for pending "+
				"channels: %v", err)
			return false
		}

		predErr = checkNumForceClosedChannels(pendingChanResp, 0)

		return predErr == nil

	}, defaultTimeout)
	if err != nil {
		t.Fatalf("channels not marked as fully resolved: %v", predErr)
	}

	testReconnection(carol)

	// Finally, we'll ensure that Bob and Carol no longer show in Alice's
	// channel graph.
	describeGraphReq := &lnrpc.ChannelGraphRequest{
		IncludeUnannounced: true,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	channelGraph, err := net.Alice.DescribeGraph(ctxt, describeGraphReq)
	if err != nil {
		t.Fatalf("unable to query for alice's channel graph: %v", err)
	}
	for _, node := range channelGraph.Nodes {
		if node.PubKey == net.Bob.PubKeyStr {
			t.Fatalf("did not expect to find bob in the channel " +
				"graph, but did")
		}
		if node.PubKey == carol.PubKeyStr {
			t.Fatalf("did not expect to find carol in the channel " +
				"graph, but did")
		}
	}

	// Now that the test is done, we can also close the persistent link.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, persistentChanPoint, false)
}

// testDataLossProtection tests that if one of the nodes in a channel
// relationship lost state, they will detect this during channel sync, and the
// up-to-date party will force close the channel, giving the outdated party the
// opportunity to sweep its output.
func testDataLossProtection(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()
	const (
		chanAmt     = funding.MaxBtcFundingAmount
		paymentAmt  = 10000
		numInvoices = 6
	)

	// Carol will be the up-to-date party. We set --nolisten to ensure Dave
	// won't be able to connect to her and trigger the channel data
	// protection logic automatically. We also can't have Carol
	// automatically re-connect too early, otherwise DLP would be initiated
	// at the wrong moment.
	carol := net.NewNode(
		t.t, "Carol", []string{"--nolisten", "--minbackoff=1h"},
	)
	defer shutdownAndAssert(net, t, carol)

	// Dave will be the party losing his state.
	dave := net.NewNode(t.t, "Dave", nil)
	defer shutdownAndAssert(net, t, dave)

	// Before we make a channel, we'll load up Carol with some coins sent
	// directly from the miner.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, carol)

	// timeTravel is a method that will make Carol open a channel to the
	// passed node, settle a series of payments, then reset the node back
	// to the state before the payments happened. When this method returns
	// the node will be unaware of the new state updates. The returned
	// function can be used to restart the node in this state.
	timeTravel := func(node *lntest.HarnessNode) (func() error,
		*lnrpc.ChannelPoint, int64, error) {

		// We must let the node communicate with Carol before they are
		// able to open channel, so we connect them.
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		net.EnsureConnected(ctxt, t.t, carol, node)

		// We'll first open up a channel between them with a 0.5 BTC
		// value.
		ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
		chanPoint := openChannelAndAssert(
			ctxt, t, net, carol, node,
			lntest.OpenChannelParams{
				Amt: chanAmt,
			},
		)

		// With the channel open, we'll create a few invoices for the
		// node that Carol will pay to in order to advance the state of
		// the channel.
		// TODO(halseth): have dangling HTLCs on the commitment, able to
		// retrieve funds?
		payReqs, _, _, err := createPayReqs(
			node, paymentAmt, numInvoices,
		)
		if err != nil {
			t.Fatalf("unable to create pay reqs: %v", err)
		}

		// Wait for Carol to receive the channel edge from the funding
		// manager.
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		err = carol.WaitForNetworkChannelOpen(ctxt, chanPoint)
		if err != nil {
			t.Fatalf("carol didn't see the carol->%s channel "+
				"before timeout: %v", node.Name(), err)
		}

		// Send payments from Carol using 3 of the payment hashes
		// generated above.
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		err = completePaymentRequests(
			ctxt, carol, carol.RouterClient,
			payReqs[:numInvoices/2], true,
		)
		if err != nil {
			t.Fatalf("unable to send payments: %v", err)
		}

		// Next query for the node's channel state, as we sent 3
		// payments of 10k satoshis each, it should now see his balance
		// as being 30k satoshis.
		var nodeChan *lnrpc.Channel
		var predErr error
		err = wait.Predicate(func() bool {
			ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
			bChan, err := getChanInfo(ctxt, node)
			if err != nil {
				t.Fatalf("unable to get channel info: %v", err)
			}
			if bChan.LocalBalance != 30000 {
				predErr = fmt.Errorf("balance is incorrect, "+
					"got %v, expected %v",
					bChan.LocalBalance, 30000)
				return false
			}

			nodeChan = bChan
			return true
		}, defaultTimeout)
		if err != nil {
			t.Fatalf("%v", predErr)
		}

		// Grab the current commitment height (update number), we'll
		// later revert him to this state after additional updates to
		// revoke this state.
		stateNumPreCopy := nodeChan.NumUpdates

		// With the temporary file created, copy the current state into
		// the temporary file we created above. Later after more
		// updates, we'll restore this state.
		if err := net.BackupDb(node); err != nil {
			t.Fatalf("unable to copy database files: %v", err)
		}

		// Finally, send more payments from , using the remaining
		// payment hashes.
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		err = completePaymentRequests(
			ctxt, carol, carol.RouterClient,
			payReqs[numInvoices/2:], true,
		)
		if err != nil {
			t.Fatalf("unable to send payments: %v", err)
		}

		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		nodeChan, err = getChanInfo(ctxt, node)
		if err != nil {
			t.Fatalf("unable to get dave chan info: %v", err)
		}

		// Now we shutdown the node, copying over the its temporary
		// database state which has the *prior* channel state over his
		// current most up to date state. With this, we essentially
		// force the node to travel back in time within the channel's
		// history.
		if err = net.RestartNode(node, func() error {
			return net.RestoreDb(node)
		}); err != nil {
			t.Fatalf("unable to restart node: %v", err)
		}

		// Make sure the channel is still there from the PoV of the
		// node.
		assertNodeNumChannels(t, node, 1)

		// Now query for the channel state, it should show that it's at
		// a state number in the past, not the *latest* state.
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		nodeChan, err = getChanInfo(ctxt, node)
		if err != nil {
			t.Fatalf("unable to get dave chan info: %v", err)
		}
		if nodeChan.NumUpdates != stateNumPreCopy {
			t.Fatalf("db copy failed: %v", nodeChan.NumUpdates)
		}

		balReq := &lnrpc.WalletBalanceRequest{}
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		balResp, err := node.WalletBalance(ctxt, balReq)
		if err != nil {
			t.Fatalf("unable to get dave's balance: %v", err)
		}

		restart, err := net.SuspendNode(node)
		if err != nil {
			t.Fatalf("unable to suspend node: %v", err)
		}

		return restart, chanPoint, balResp.ConfirmedBalance, nil
	}

	// Reset Dave to a state where he has an outdated channel state.
	restartDave, _, daveStartingBalance, err := timeTravel(dave)
	if err != nil {
		t.Fatalf("unable to time travel dave: %v", err)
	}

	// We make a note of the nodes' current on-chain balances, to make sure
	// they are able to retrieve the channel funds eventually,
	balReq := &lnrpc.WalletBalanceRequest{}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	carolBalResp, err := carol.WalletBalance(ctxt, balReq)
	if err != nil {
		t.Fatalf("unable to get carol's balance: %v", err)
	}
	carolStartingBalance := carolBalResp.ConfirmedBalance

	// Restart Dave to trigger a channel resync.
	if err := restartDave(); err != nil {
		t.Fatalf("unable to restart dave: %v", err)
	}

	// Assert that once Dave comes up, they reconnect, Carol force closes
	// on chain, and both of them properly carry out the DLP protocol.
	assertDLPExecuted(
		net, t, carol, carolStartingBalance, dave, daveStartingBalance,
		false,
	)

	// As a second part of this test, we will test the scenario where a
	// channel is closed while Dave is offline, loses his state and comes
	// back online. In this case the node should attempt to resync the
	// channel, and the peer should resend a channel sync message for the
	// closed channel, such that Dave can retrieve his funds.
	//
	// We start by letting Dave time travel back to an outdated state.
	restartDave, chanPoint2, daveStartingBalance, err := timeTravel(dave)
	if err != nil {
		t.Fatalf("unable to time travel eve: %v", err)
	}

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	carolBalResp, err = carol.WalletBalance(ctxt, balReq)
	if err != nil {
		t.Fatalf("unable to get carol's balance: %v", err)
	}
	carolStartingBalance = carolBalResp.ConfirmedBalance

	// Now let Carol force close the channel while Dave is offline.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, carol, chanPoint2, true)

	// Wait for the channel to be marked pending force close.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = waitForChannelPendingForceClose(ctxt, carol, chanPoint2)
	if err != nil {
		t.Fatalf("channel not pending force close: %v", err)
	}

	// Mine enough blocks for Carol to sweep her funds.
	mineBlocks(t, net, defaultCSV-1, 0)

	carolSweep, err := waitForTxInMempool(net.Miner.Client, minerMempoolTimeout)
	if err != nil {
		t.Fatalf("unable to find Carol's sweep tx in mempool: %v", err)
	}
	block := mineBlocks(t, net, 1, 1)[0]
	assertTxInBlock(t, block, carolSweep)

	// Now the channel should be fully closed also from Carol's POV.
	assertNumPendingChannels(t, carol, 0, 0)

	// Make sure Carol got her balance back.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	carolBalResp, err = carol.WalletBalance(ctxt, balReq)
	if err != nil {
		t.Fatalf("unable to get carol's balance: %v", err)
	}
	carolBalance := carolBalResp.ConfirmedBalance
	if carolBalance <= carolStartingBalance {
		t.Fatalf("expected carol to have balance above %d, "+
			"instead had %v", carolStartingBalance,
			carolBalance)
	}

	assertNodeNumChannels(t, carol, 0)

	// When Dave comes online, he will reconnect to Carol, try to resync
	// the channel, but it will already be closed. Carol should resend the
	// information Dave needs to sweep his funds.
	if err := restartDave(); err != nil {
		t.Fatalf("unable to restart Eve: %v", err)
	}

	// Dave should sweep his funds.
	_, err = waitForTxInMempool(net.Miner.Client, minerMempoolTimeout)
	if err != nil {
		t.Fatalf("unable to find Dave's sweep tx in mempool: %v", err)
	}

	// Mine a block to confirm the sweep, and make sure Dave got his
	// balance back.
	mineBlocks(t, net, 1, 1)
	assertNodeNumChannels(t, dave, 0)

	err = wait.NoError(func() error {
		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
		daveBalResp, err := dave.WalletBalance(ctxt, balReq)
		if err != nil {
			return fmt.Errorf("unable to get dave's balance: %v",
				err)
		}

		daveBalance := daveBalResp.ConfirmedBalance
		if daveBalance <= daveStartingBalance {
			return fmt.Errorf("expected dave to have balance "+
				"above %d, intead had %v", daveStartingBalance,
				daveBalance)
		}

		return nil
	}, defaultTimeout)
	if err != nil {
		t.Fatalf("%v", err)
	}
}

// testRejectHTLC tests that a node can be created with the flag --rejecthtlc.
// This means that the node will reject all forwarded HTLCs but can still
// accept direct HTLCs as well as send HTLCs.
func testRejectHTLC(net *lntest.NetworkHarness, t *harnessTest) {
	//             RejectHTLC
	// Alice ------> Carol ------> Bob
	//
	const chanAmt = btcutil.Amount(1000000)
	ctxb := context.Background()

	// Create Carol with reject htlc flag.
	carol := net.NewNode(t.t, "Carol", []string{"--rejecthtlc"})
	defer shutdownAndAssert(net, t, carol)

	// Connect Alice to Carol.
	net.ConnectNodes(ctxb, t.t, net.Alice, carol)

	// Connect Carol to Bob.
	net.ConnectNodes(ctxb, t.t, carol, net.Bob)

	// Send coins to Carol.
	net.SendCoins(ctxb, t.t, btcutil.SatoshiPerBitcoin, carol)

	// Send coins to Alice.
	net.SendCoins(ctxb, t.t, btcutil.SatoshiPerBitcent, net.Alice)

	// Open a channel between Alice and Carol.
	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointAlice := openChannelAndAssert(
		ctxt, t, net, net.Alice, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Open a channel between Carol and Bob.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointCarol := openChannelAndAssert(
		ctxt, t, net, carol, net.Bob,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Channel should be ready for payments.
	const payAmt = 100

	// Helper closure to generate a random pre image.
	genPreImage := func() []byte {
		preimage := make([]byte, 32)

		_, err := rand.Read(preimage)
		if err != nil {
			t.Fatalf("unable to generate preimage: %v", err)
		}

		return preimage
	}

	// Create an invoice from Carol of 100 satoshis.
	// We expect Alice to be able to pay this invoice.
	preimage := genPreImage()

	carolInvoice := &lnrpc.Invoice{
		Memo:      "testing - alice should pay carol",
		RPreimage: preimage,
		Value:     payAmt,
	}

	// Carol adds the invoice to her database.
	resp, err := carol.AddInvoice(ctxb, carolInvoice)
	if err != nil {
		t.Fatalf("unable to add invoice: %v", err)
	}

	// Alice pays Carols invoice.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = completePaymentRequests(
		ctxt, net.Alice, net.Alice.RouterClient,
		[]string{resp.PaymentRequest}, true,
	)
	if err != nil {
		t.Fatalf("unable to send payments from alice to carol: %v", err)
	}

	// Create an invoice from Bob of 100 satoshis.
	// We expect Carol to be able to pay this invoice.
	preimage = genPreImage()

	bobInvoice := &lnrpc.Invoice{
		Memo:      "testing - carol should pay bob",
		RPreimage: preimage,
		Value:     payAmt,
	}

	// Bob adds the invoice to his database.
	resp, err = net.Bob.AddInvoice(ctxb, bobInvoice)
	if err != nil {
		t.Fatalf("unable to add invoice: %v", err)
	}

	// Carol pays Bobs invoice.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = completePaymentRequests(
		ctxt, carol, carol.RouterClient,
		[]string{resp.PaymentRequest}, true,
	)
	if err != nil {
		t.Fatalf("unable to send payments from carol to bob: %v", err)
	}

	// Create an invoice from Bob of 100 satoshis.
	// Alice attempts to pay Bob but this should fail, since we are
	// using Carol as a hop and her node will reject onward HTLCs.
	preimage = genPreImage()

	bobInvoice = &lnrpc.Invoice{
		Memo:      "testing - alice tries to pay bob",
		RPreimage: preimage,
		Value:     payAmt,
	}

	// Bob adds the invoice to his database.
	resp, err = net.Bob.AddInvoice(ctxb, bobInvoice)
	if err != nil {
		t.Fatalf("unable to add invoice: %v", err)
	}

	// Alice attempts to pay Bobs invoice. This payment should be rejected since
	// we are using Carol as an intermediary hop, Carol is running lnd with
	// --rejecthtlc.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = completePaymentRequests(
		ctxt, net.Alice, net.Alice.RouterClient,
		[]string{resp.PaymentRequest}, true,
	)
	if err == nil {
		t.Fatalf(
			"should have been rejected, carol will not accept forwarded htlcs",
		)
	}

	assertLastHTLCError(t, net.Alice, lnrpc.Failure_CHANNEL_DISABLED)

	// Close all channels.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, chanPointAlice, false)
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, carol, chanPointCarol, false)
}

func testGraphTopologyNotifications(net *lntest.NetworkHarness, t *harnessTest) {
	t.t.Run("pinned", func(t *testing.T) {
		ht := newHarnessTest(t, net)
		testGraphTopologyNtfns(net, ht, true)
	})
	t.t.Run("unpinned", func(t *testing.T) {
		ht := newHarnessTest(t, net)
		testGraphTopologyNtfns(net, ht, false)
	})
}

func testGraphTopologyNtfns(net *lntest.NetworkHarness, t *harnessTest, pinned bool) {
	ctxb := context.Background()

	const chanAmt = funding.MaxBtcFundingAmount

	// Spin up Bob first, since we will need to grab his pubkey when
	// starting Alice to test pinned syncing.
	bob := net.NewNode(t.t, "bob", nil)
	defer shutdownAndAssert(net, t, bob)

	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	bobInfo, err := bob.GetInfo(ctxt, &lnrpc.GetInfoRequest{})
	require.NoError(t.t, err)
	bobPubkey := bobInfo.IdentityPubkey

	// For unpinned syncing, start Alice as usual. Otherwise grab Bob's
	// pubkey to include in his pinned syncer set.
	var aliceArgs []string
	if pinned {
		aliceArgs = []string{
			"--numgraphsyncpeers=0",
			fmt.Sprintf("--gossip.pinned-syncers=%s", bobPubkey),
		}
	}

	alice := net.NewNode(t.t, "alice", aliceArgs)
	defer shutdownAndAssert(net, t, alice)

	// Connect Alice and Bob.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, alice, bob)

	// Alice stimmy.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, alice)

	// Bob stimmy.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, bob)

	// Assert that Bob has the correct sync type before proceeeding.
	if pinned {
		assertSyncType(t, alice, bobPubkey, lnrpc.Peer_PINNED_SYNC)
	} else {
		assertSyncType(t, alice, bobPubkey, lnrpc.Peer_ACTIVE_SYNC)
	}

	// Regardless of syncer type, ensure that both peers report having
	// completed their initial sync before continuing to make a channel.
	waitForGraphSync(t, alice)

	// Let Alice subscribe to graph notifications.
	graphSub := subscribeGraphNotifications(ctxb, t, alice)
	defer close(graphSub.quit)

	// Open a new channel between Alice and Bob.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, alice, bob,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// The channel opening above should have triggered a few notifications
	// sent to the notification client. We'll expect two channel updates,
	// and two node announcements.
	var numChannelUpds int
	var numNodeAnns int
	for numChannelUpds < 2 && numNodeAnns < 2 {
		select {
		// Ensure that a new update for both created edges is properly
		// dispatched to our registered client.
		case graphUpdate := <-graphSub.updateChan:
			// Process all channel updates prsented in this update
			// message.
			for _, chanUpdate := range graphUpdate.ChannelUpdates {
				switch chanUpdate.AdvertisingNode {
				case alice.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown advertising node: %v",
						chanUpdate.AdvertisingNode)
				}
				switch chanUpdate.ConnectingNode {
				case alice.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown connecting node: %v",
						chanUpdate.ConnectingNode)
				}

				if chanUpdate.Capacity != int64(chanAmt) {
					t.Fatalf("channel capacities mismatch:"+
						" expected %v, got %v", chanAmt,
						btcutil.Amount(chanUpdate.Capacity))
				}
				numChannelUpds++
			}

			for _, nodeUpdate := range graphUpdate.NodeUpdates {
				switch nodeUpdate.IdentityKey {
				case alice.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown node: %v",
						nodeUpdate.IdentityKey)
				}
				numNodeAnns++
			}
		case err := <-graphSub.errChan:
			t.Fatalf("unable to recv graph update: %v", err)
		case <-time.After(time.Second * 10):
			t.Fatalf("timeout waiting for graph notifications, "+
				"only received %d/2 chanupds and %d/2 nodeanns",
				numChannelUpds, numNodeAnns)
		}
	}

	_, blockHeight, err := net.Miner.Client.GetBestBlock()
	if err != nil {
		t.Fatalf("unable to get current blockheight %v", err)
	}

	// Now we'll test that updates are properly sent after channels are closed
	// within the network.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, alice, chanPoint, false)

	// Now that the channel has been closed, we should receive a
	// notification indicating so.
out:
	for {
		select {
		case graphUpdate := <-graphSub.updateChan:
			if len(graphUpdate.ClosedChans) != 1 {
				continue
			}

			closedChan := graphUpdate.ClosedChans[0]
			if closedChan.ClosedHeight != uint32(blockHeight+1) {
				t.Fatalf("close heights of channel mismatch: "+
					"expected %v, got %v", blockHeight+1,
					closedChan.ClosedHeight)
			}
			chanPointTxid, err := lnrpc.GetChanPointFundingTxid(chanPoint)
			if err != nil {
				t.Fatalf("unable to get txid: %v", err)
			}
			closedChanTxid, err := lnrpc.GetChanPointFundingTxid(
				closedChan.ChanPoint,
			)
			if err != nil {
				t.Fatalf("unable to get txid: %v", err)
			}
			if !bytes.Equal(closedChanTxid[:], chanPointTxid[:]) {
				t.Fatalf("channel point hash mismatch: "+
					"expected %v, got %v", chanPointTxid,
					closedChanTxid)
			}
			if closedChan.ChanPoint.OutputIndex != chanPoint.OutputIndex {
				t.Fatalf("output index mismatch: expected %v, "+
					"got %v", chanPoint.OutputIndex,
					closedChan.ChanPoint)
			}

			break out

		case err := <-graphSub.errChan:
			t.Fatalf("unable to recv graph update: %v", err)
		case <-time.After(time.Second * 10):
			t.Fatalf("notification for channel closure not " +
				"sent")
		}
	}

	// For the final portion of the test, we'll ensure that once a new node
	// appears in the network, the proper notification is dispatched. Note
	// that a node that does not have any channels open is ignored, so first
	// we disconnect Alice and Bob, open a channel between Bob and Carol,
	// and finally connect Alice to Bob again.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, alice, bob); err != nil {
		t.Fatalf("unable to disconnect alice and bob: %v", err)
	}
	carol := net.NewNode(t.t, "Carol", nil)
	defer shutdownAndAssert(net, t, carol)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, bob, carol)
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint = openChannelAndAssert(
		ctxt, t, net, bob, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Reconnect Alice and Bob. This should result in the nodes syncing up
	// their respective graph state, with the new addition being the
	// existence of Carol in the graph, and also the channel between Bob
	// and Carol. Note that we will also receive a node announcement from
	// Bob, since a node will update its node announcement after a new
	// channel is opened.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, alice, bob)

	// We should receive an update advertising the newly connected node,
	// Bob's new node announcement, and the channel between Bob and Carol.
	numNodeAnns = 0
	numChannelUpds = 0
	for numChannelUpds < 2 && numNodeAnns < 1 {
		select {
		case graphUpdate := <-graphSub.updateChan:
			for _, nodeUpdate := range graphUpdate.NodeUpdates {
				switch nodeUpdate.IdentityKey {
				case carol.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown node update pubey: %v",
						nodeUpdate.IdentityKey)
				}
				numNodeAnns++
			}

			for _, chanUpdate := range graphUpdate.ChannelUpdates {
				switch chanUpdate.AdvertisingNode {
				case carol.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown advertising node: %v",
						chanUpdate.AdvertisingNode)
				}
				switch chanUpdate.ConnectingNode {
				case carol.PubKeyStr:
				case bob.PubKeyStr:
				default:
					t.Fatalf("unknown connecting node: %v",
						chanUpdate.ConnectingNode)
				}

				if chanUpdate.Capacity != int64(chanAmt) {
					t.Fatalf("channel capacities mismatch:"+
						" expected %v, got %v", chanAmt,
						btcutil.Amount(chanUpdate.Capacity))
				}
				numChannelUpds++
			}
		case err := <-graphSub.errChan:
			t.Fatalf("unable to recv graph update: %v", err)
		case <-time.After(time.Second * 10):
			t.Fatalf("timeout waiting for graph notifications, "+
				"only received %d/2 chanupds and %d/2 nodeanns",
				numChannelUpds, numNodeAnns)
		}
	}

	// Close the channel between Bob and Carol.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, bob, chanPoint, false)
}

// testNodeAnnouncement ensures that when a node is started with one or more
// external IP addresses specified on the command line, that those addresses
// announced to the network and reported in the network graph.
func testNodeAnnouncement(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	aliceSub := subscribeGraphNotifications(ctxb, t, net.Alice)
	defer close(aliceSub.quit)

	advertisedAddrs := []string{
		"192.168.1.1:8333",
		"[2001:db8:85a3:8d3:1319:8a2e:370:7348]:8337",
		"bkb6azqggsaiskzi.onion:9735",
		"fomvuglh6h6vcag73xo5t5gv56ombih3zr2xvplkpbfd7wrog4swjwid.onion:1234",
	}

	var lndArgs []string
	for _, addr := range advertisedAddrs {
		lndArgs = append(lndArgs, "--externalip="+addr)
	}

	dave := net.NewNode(t.t, "Dave", lndArgs)
	defer shutdownAndAssert(net, t, dave)

	// We must let Dave have an open channel before he can send a node
	// announcement, so we open a channel with Bob,
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, net.Bob, dave)

	// Alice shouldn't receive any new updates yet since the channel has yet
	// to be opened.
	select {
	case <-aliceSub.updateChan:
		t.Fatalf("received unexpected update from dave")
	case <-time.After(time.Second):
	}

	// We'll then go ahead and open a channel between Bob and Dave. This
	// ensures that Alice receives the node announcement from Bob as part of
	// the announcement broadcast.
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, net.Bob, dave,
		lntest.OpenChannelParams{
			Amt: 1000000,
		},
	)

	assertAddrs := func(addrsFound []string, targetAddrs ...string) {
		addrs := make(map[string]struct{}, len(addrsFound))
		for _, addr := range addrsFound {
			addrs[addr] = struct{}{}
		}

		for _, addr := range targetAddrs {
			if _, ok := addrs[addr]; !ok {
				t.Fatalf("address %v not found in node "+
					"announcement", addr)
			}
		}
	}

	waitForAddrsInUpdate := func(graphSub graphSubscription,
		nodePubKey string, targetAddrs ...string) {

		for {
			select {
			case graphUpdate := <-graphSub.updateChan:
				for _, update := range graphUpdate.NodeUpdates {
					if update.IdentityKey == nodePubKey {
						assertAddrs(
							update.Addresses, // nolint:staticcheck
							targetAddrs...,
						)
						return
					}
				}
			case err := <-graphSub.errChan:
				t.Fatalf("unable to recv graph update: %v", err)
			case <-time.After(defaultTimeout):
				t.Fatalf("did not receive node ann update")
			}
		}
	}

	// We'll then wait for Alice to receive Dave's node announcement
	// including the expected advertised addresses from Bob since they
	// should already be connected.
	waitForAddrsInUpdate(
		aliceSub, dave.PubKeyStr, advertisedAddrs...,
	)

	// Close the channel between Bob and Dave.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Bob, chanPoint, false)
}

func testNodeSignVerify(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	chanAmt := funding.MaxBtcFundingAmount
	pushAmt := btcutil.Amount(100000)

	// Create a channel between alice and bob.
	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	aliceBobCh := openChannelAndAssert(
		ctxt, t, net, net.Alice, net.Bob,
		lntest.OpenChannelParams{
			Amt:     chanAmt,
			PushAmt: pushAmt,
		},
	)

	aliceMsg := []byte("alice msg")

	// alice signs "alice msg" and sends her signature to bob.
	sigReq := &lnrpc.SignMessageRequest{Msg: aliceMsg}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	sigResp, err := net.Alice.SignMessage(ctxt, sigReq)
	if err != nil {
		t.Fatalf("SignMessage rpc call failed: %v", err)
	}
	aliceSig := sigResp.Signature

	// bob verifying alice's signature should succeed since alice and bob are
	// connected.
	verifyReq := &lnrpc.VerifyMessageRequest{Msg: aliceMsg, Signature: aliceSig}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	verifyResp, err := net.Bob.VerifyMessage(ctxt, verifyReq)
	if err != nil {
		t.Fatalf("VerifyMessage failed: %v", err)
	}
	if !verifyResp.Valid {
		t.Fatalf("alice's signature didn't validate")
	}
	if verifyResp.Pubkey != net.Alice.PubKeyStr {
		t.Fatalf("alice's signature doesn't contain alice's pubkey.")
	}

	// carol is a new node that is unconnected to alice or bob.
	carol := net.NewNode(t.t, "Carol", nil)
	defer shutdownAndAssert(net, t, carol)

	carolMsg := []byte("carol msg")

	// carol signs "carol msg" and sends her signature to bob.
	sigReq = &lnrpc.SignMessageRequest{Msg: carolMsg}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	sigResp, err = carol.SignMessage(ctxt, sigReq)
	if err != nil {
		t.Fatalf("SignMessage rpc call failed: %v", err)
	}
	carolSig := sigResp.Signature

	// bob verifying carol's signature should fail since they are not connected.
	verifyReq = &lnrpc.VerifyMessageRequest{Msg: carolMsg, Signature: carolSig}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	verifyResp, err = net.Bob.VerifyMessage(ctxt, verifyReq)
	if err != nil {
		t.Fatalf("VerifyMessage failed: %v", err)
	}
	if verifyResp.Valid {
		t.Fatalf("carol's signature should not be valid")
	}
	if verifyResp.Pubkey != carol.PubKeyStr {
		t.Fatalf("carol's signature doesn't contain her pubkey")
	}

	// Close the channel between alice and bob.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Alice, aliceBobCh, false)
}

// testSendUpdateDisableChannel ensures that a channel update with the disable
// flag set is sent once a channel has been either unilaterally or cooperatively
// closed.
func testSendUpdateDisableChannel(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	const (
		chanAmt = 100000
	)

	// Open a channel between Alice and Bob and Alice and Carol. These will
	// be closed later on in order to trigger channel update messages
	// marking the channels as disabled.
	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointAliceBob := openChannelAndAssert(
		ctxt, t, net, net.Alice, net.Bob,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	carol := net.NewNode(
		t.t, "Carol", []string{
			"--minbackoff=10s",
			"--chan-enable-timeout=1.5s",
			"--chan-disable-timeout=3s",
			"--chan-status-sample-interval=.5s",
		})
	defer shutdownAndAssert(net, t, carol)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, net.Alice, carol)
	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointAliceCarol := openChannelAndAssert(
		ctxt, t, net, net.Alice, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// We create a new node Eve that has an inactive channel timeout of
	// just 2 seconds (down from the default 20m). It will be used to test
	// channel updates for channels going inactive.
	eve := net.NewNode(
		t.t, "Eve", []string{
			"--minbackoff=10s",
			"--chan-enable-timeout=1.5s",
			"--chan-disable-timeout=3s",
			"--chan-status-sample-interval=.5s",
		})
	defer shutdownAndAssert(net, t, eve)

	// Give Eve some coins.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, eve)

	// Connect Eve to Carol and Bob, and open a channel to carol.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, eve, carol)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, eve, net.Bob)

	ctxt, _ = context.WithTimeout(ctxb, channelOpenTimeout)
	chanPointEveCarol := openChannelAndAssert(
		ctxt, t, net, eve, carol,
		lntest.OpenChannelParams{
			Amt: chanAmt,
		},
	)

	// Launch a node for Dave which will connect to Bob in order to receive
	// graph updates from. This will ensure that the channel updates are
	// propagated throughout the network.
	dave := net.NewNode(t.t, "Dave", nil)
	defer shutdownAndAssert(net, t, dave)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.ConnectNodes(ctxt, t.t, net.Bob, dave)

	daveSub := subscribeGraphNotifications(ctxb, t, dave)
	defer close(daveSub.quit)

	// We should expect to see a channel update with the default routing
	// policy, except that it should indicate the channel is disabled.
	expectedPolicy := &lnrpc.RoutingPolicy{
		FeeBaseMsat:      int64(chainreg.DefaultBitcoinBaseFeeMSat),
		FeeRateMilliMsat: int64(chainreg.DefaultBitcoinFeeRate),
		TimeLockDelta:    chainreg.DefaultBitcoinTimeLockDelta,
		MinHtlc:          1000, // default value
		MaxHtlcMsat:      calculateMaxHtlc(chanAmt),
		Disabled:         true,
	}

	// Let Carol go offline. Since Eve has an inactive timeout of 2s, we
	// expect her to send an update disabling the channel.
	restartCarol, err := net.SuspendNode(carol)
	if err != nil {
		t.Fatalf("unable to suspend carol: %v", err)
	}
	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{eve.PubKeyStr, expectedPolicy, chanPointEveCarol},
		},
	)

	// We restart Carol. Since the channel now becomes active again, Eve
	// should send a ChannelUpdate setting the channel no longer disabled.
	if err := restartCarol(); err != nil {
		t.Fatalf("unable to restart carol: %v", err)
	}

	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{eve.PubKeyStr, expectedPolicy, chanPointEveCarol},
		},
	)

	// Now we'll test a long disconnection. Disconnect Carol and Eve and
	// ensure they both detect each other as disabled. Their min backoffs
	// are high enough to not interfere with disabling logic.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, carol, eve); err != nil {
		t.Fatalf("unable to disconnect Carol from Eve: %v", err)
	}

	// Wait for a disable from both Carol and Eve to come through.
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{eve.PubKeyStr, expectedPolicy, chanPointEveCarol},
			{carol.PubKeyStr, expectedPolicy, chanPointEveCarol},
		},
	)

	// Reconnect Carol and Eve, this should cause them to reenable the
	// channel from both ends after a short delay.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, carol, eve)

	expectedPolicy.Disabled = false
	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{eve.PubKeyStr, expectedPolicy, chanPointEveCarol},
			{carol.PubKeyStr, expectedPolicy, chanPointEveCarol},
		},
	)

	// Now we'll test a short disconnection. Disconnect Carol and Eve, then
	// reconnect them after one second so that their scheduled disables are
	// aborted. One second is twice the status sample interval, so this
	// should allow for the disconnect to be detected, but still leave time
	// to cancel the announcement before the 3 second inactive timeout is
	// hit.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	if err := net.DisconnectNodes(ctxt, carol, eve); err != nil {
		t.Fatalf("unable to disconnect Carol from Eve: %v", err)
	}
	time.Sleep(time.Second)
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.EnsureConnected(ctxt, t.t, eve, carol)

	// Since the disable should have been canceled by both Carol and Eve, we
	// expect no channel updates to appear on the network.
	assertNoChannelUpdates(t, daveSub, 4*time.Second)

	// Close Alice's channels with Bob and Carol cooperatively and
	// unilaterally respectively.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	_, _, err = net.CloseChannel(ctxt, net.Alice, chanPointAliceBob, false)
	if err != nil {
		t.Fatalf("unable to close channel: %v", err)
	}

	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	_, _, err = net.CloseChannel(ctxt, net.Alice, chanPointAliceCarol, true)
	if err != nil {
		t.Fatalf("unable to close channel: %v", err)
	}

	// Now that the channel close processes have been started, we should
	// receive an update marking each as disabled.
	expectedPolicy.Disabled = true
	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{net.Alice.PubKeyStr, expectedPolicy, chanPointAliceBob},
			{net.Alice.PubKeyStr, expectedPolicy, chanPointAliceCarol},
		},
	)

	// Finally, close the channels by mining the closing transactions.
	mineBlocks(t, net, 1, 2)

	// Also do this check for Eve's channel with Carol.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	_, _, err = net.CloseChannel(ctxt, eve, chanPointEveCarol, false)
	if err != nil {
		t.Fatalf("unable to close channel: %v", err)
	}

	waitForChannelUpdate(
		t, daveSub,
		[]expectedChanUpdate{
			{eve.PubKeyStr, expectedPolicy, chanPointEveCarol},
		},
	)
	mineBlocks(t, net, 1, 1)

	// And finally, clean up the force closed channel by mining the
	// sweeping transaction.
	cleanupForceClose(t, net, net.Alice, chanPointAliceCarol)
}

// testAbandonChannel abandones a channel and asserts that it is no
// longer open and not in one of the pending closure states. It also
// verifies that the abandoned channel is reported as closed with close
// type 'abandoned'.
func testAbandonChannel(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// First establish a channel between Alice and Bob.
	channelParam := lntest.OpenChannelParams{
		Amt:     funding.MaxBtcFundingAmount,
		PushAmt: btcutil.Amount(100000),
	}

	ctxt, _ := context.WithTimeout(ctxb, channelOpenTimeout)
	chanPoint := openChannelAndAssert(
		ctxt, t, net, net.Alice, net.Bob, channelParam,
	)
	txid, err := lnrpc.GetChanPointFundingTxid(chanPoint)
	if err != nil {
		t.Fatalf("unable to get txid: %v", err)
	}
	chanPointStr := fmt.Sprintf("%v:%v", txid, chanPoint.OutputIndex)

	// Wait for channel to be confirmed open.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	err = net.Alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("alice didn't report channel: %v", err)
	}
	err = net.Bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
	if err != nil {
		t.Fatalf("bob didn't report channel: %v", err)
	}

	// Now that the channel is open, we'll obtain its channel ID real quick
	// so we can use it to query the graph below.
	listReq := &lnrpc.ListChannelsRequest{}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	aliceChannelList, err := net.Alice.ListChannels(ctxt, listReq)
	if err != nil {
		t.Fatalf("unable to fetch alice's channels: %v", err)
	}
	var chanID uint64
	for _, channel := range aliceChannelList.Channels {
		if channel.ChannelPoint == chanPointStr {
			chanID = channel.ChanId
		}
	}

	if chanID == 0 {
		t.Fatalf("unable to find channel")
	}

	// To make sure the channel is removed from the backup file as well when
	// being abandoned, grab a backup snapshot so we can compare it with the
	// later state.
	bkupBefore, err := ioutil.ReadFile(net.Alice.ChanBackupPath())
	if err != nil {
		t.Fatalf("could not get channel backup before abandoning "+
			"channel: %v", err)
	}

	// Send request to abandon channel.
	abandonChannelRequest := &lnrpc.AbandonChannelRequest{
		ChannelPoint: chanPoint,
	}

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	_, err = net.Alice.AbandonChannel(ctxt, abandonChannelRequest)
	if err != nil {
		t.Fatalf("unable to abandon channel: %v", err)
	}

	// Assert that channel in no longer open.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	aliceChannelList, err = net.Alice.ListChannels(ctxt, listReq)
	if err != nil {
		t.Fatalf("unable to list channels: %v", err)
	}
	if len(aliceChannelList.Channels) != 0 {
		t.Fatalf("alice should only have no channels open, "+
			"instead she has %v",
			len(aliceChannelList.Channels))
	}

	// Assert that channel is not pending closure.
	pendingReq := &lnrpc.PendingChannelsRequest{}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	alicePendingList, err := net.Alice.PendingChannels(ctxt, pendingReq)
	if err != nil {
		t.Fatalf("unable to list pending channels: %v", err)
	}
	if len(alicePendingList.PendingClosingChannels) != 0 { //nolint:staticcheck
		t.Fatalf("alice should only have no pending closing channels, "+
			"instead she has %v",
			len(alicePendingList.PendingClosingChannels)) //nolint:staticcheck
	}
	if len(alicePendingList.PendingForceClosingChannels) != 0 {
		t.Fatalf("alice should only have no pending force closing "+
			"channels instead she has %v",
			len(alicePendingList.PendingForceClosingChannels))
	}
	if len(alicePendingList.WaitingCloseChannels) != 0 {
		t.Fatalf("alice should only have no waiting close "+
			"channels instead she has %v",
			len(alicePendingList.WaitingCloseChannels))
	}

	// Assert that channel is listed as abandoned.
	closedReq := &lnrpc.ClosedChannelsRequest{
		Abandoned: true,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	aliceClosedList, err := net.Alice.ClosedChannels(ctxt, closedReq)
	if err != nil {
		t.Fatalf("unable to list closed channels: %v", err)
	}
	if len(aliceClosedList.Channels) != 1 {
		t.Fatalf("alice should only have a single abandoned channel, "+
			"instead she has %v",
			len(aliceClosedList.Channels))
	}

	// Ensure that the channel can no longer be found in the channel graph.
	_, err = net.Alice.GetChanInfo(ctxb, &lnrpc.ChanInfoRequest{
		ChanId: chanID,
	})
	if !strings.Contains(err.Error(), "marked as zombie") {
		t.Fatalf("channel shouldn't be found in the channel " +
			"graph!")
	}

	// Make sure the channel is no longer in the channel backup list.
	err = wait.Predicate(func() bool {
		bkupAfter, err := ioutil.ReadFile(net.Alice.ChanBackupPath())
		if err != nil {
			t.Fatalf("could not get channel backup before "+
				"abandoning channel: %v", err)
		}

		return len(bkupAfter) < len(bkupBefore)
	}, defaultTimeout)
	if err != nil {
		t.Fatalf("channel wasn't removed from channel backup file")
	}

	// Calling AbandonChannel again, should result in no new errors, as the
	// channel has already been removed.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	_, err = net.Alice.AbandonChannel(ctxt, abandonChannelRequest)
	if err != nil {
		t.Fatalf("unable to abandon channel a second time: %v", err)
	}

	// Now that we're done with the test, the channel can be closed. This
	// is necessary to avoid unexpected outcomes of other tests that use
	// Bob's lnd instance.
	ctxt, _ = context.WithTimeout(ctxb, channelCloseTimeout)
	closeChannelAndAssert(ctxt, t, net, net.Bob, chanPoint, true)

	// Cleanup by mining the force close and sweep transaction.
	cleanupForceClose(t, net, net.Bob, chanPoint)
}

// testSweepAllCoins tests that we're able to properly sweep all coins from the
// wallet into a single target address at the specified fee rate.
func testSweepAllCoins(net *lntest.NetworkHarness, t *harnessTest) {
	ctxb := context.Background()

	// First, we'll make a new node, ainz who'll we'll use to test wallet
	// sweeping.
	ainz := net.NewNode(t.t, "Ainz", nil)
	defer shutdownAndAssert(net, t, ainz)

	// Next, we'll give Ainz exactly 2 utxos of 1 BTC each, with one of
	// them being p2wkh and the other being a n2wpkh address.
	ctxt, _ := context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoins(ctxt, t.t, btcutil.SatoshiPerBitcoin, ainz)

	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	net.SendCoinsNP2WKH(ctxt, t.t, btcutil.SatoshiPerBitcoin, ainz)

	// Ensure that we can't send coins to our own Pubkey.
	info, err := ainz.GetInfo(ctxt, &lnrpc.GetInfoRequest{})
	if err != nil {
		t.Fatalf("unable to get node info: %v", err)
	}

	// Create a label that we will used to label the transaction with.
	sendCoinsLabel := "send all coins"

	sweepReq := &lnrpc.SendCoinsRequest{
		Addr:    info.IdentityPubkey,
		SendAll: true,
		Label:   sendCoinsLabel,
	}
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err == nil {
		t.Fatalf("expected SendCoins to users own pubkey to fail")
	}

	// Ensure that we can't send coins to another users Pubkey.
	info, err = net.Alice.GetInfo(ctxt, &lnrpc.GetInfoRequest{})
	if err != nil {
		t.Fatalf("unable to get node info: %v", err)
	}

	sweepReq = &lnrpc.SendCoinsRequest{
		Addr:    info.IdentityPubkey,
		SendAll: true,
		Label:   sendCoinsLabel,
	}
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err == nil {
		t.Fatalf("expected SendCoins to Alices pubkey to fail")
	}

	// With the two coins above mined, we'll now instruct ainz to sweep all
	// the coins to an external address not under its control.
	// We will first attempt to send the coins to addresses that are not
	// compatible with the current network. This is to test that the wallet
	// will prevent any onchain transactions to addresses that are not on the
	// same network as the user.

	// Send coins to a testnet3 address.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	sweepReq = &lnrpc.SendCoinsRequest{
		Addr:    "tb1qfc8fusa98jx8uvnhzavxccqlzvg749tvjw82tg",
		SendAll: true,
		Label:   sendCoinsLabel,
	}
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err == nil {
		t.Fatalf("expected SendCoins to different network to fail")
	}

	// Send coins to a mainnet address.
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	sweepReq = &lnrpc.SendCoinsRequest{
		Addr:    "1MPaXKp5HhsLNjVSqaL7fChE3TVyrTMRT3",
		SendAll: true,
		Label:   sendCoinsLabel,
	}
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err == nil {
		t.Fatalf("expected SendCoins to different network to fail")
	}

	// Send coins to a compatible address.
	minerAddr, err := net.Miner.NewAddress()
	if err != nil {
		t.Fatalf("unable to create new miner addr: %v", err)
	}

	sweepReq = &lnrpc.SendCoinsRequest{
		Addr:    minerAddr.String(),
		SendAll: true,
		Label:   sendCoinsLabel,
	}
	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err != nil {
		t.Fatalf("unable to sweep coins: %v", err)
	}

	// We'll mine a block which should include the sweep transaction we
	// generated above.
	block := mineBlocks(t, net, 1, 1)[0]

	// The sweep transaction should have exactly two inputs as we only had
	// two UTXOs in the wallet.
	sweepTx := block.Transactions[1]
	if len(sweepTx.TxIn) != 2 {
		t.Fatalf("expected 2 inputs instead have %v", len(sweepTx.TxIn))
	}

	sweepTxStr := sweepTx.TxHash().String()
	assertTxLabel(ctxb, t, ainz, sweepTxStr, sendCoinsLabel)

	// While we are looking at labels, we test our label transaction command
	// to make sure it is behaving as expected. First, we try to label our
	// transaction with an empty label, and check that we fail as expected.
	sweepHash := sweepTx.TxHash()
	_, err = ainz.WalletKitClient.LabelTransaction(
		ctxt, &walletrpc.LabelTransactionRequest{
			Txid:      sweepHash[:],
			Label:     "",
			Overwrite: false,
		},
	)
	if err == nil {
		t.Fatalf("expected error for zero transaction label")
	}

	// Our error will be wrapped in a rpc error, so we check that it
	// contains the error we expect.
	errZeroLabel := "cannot label transaction with empty label"
	if !strings.Contains(err.Error(), errZeroLabel) {
		t.Fatalf("expected: zero label error, got: %v", err)
	}

	// Next, we try to relabel our transaction without setting the overwrite
	// boolean. We expect this to fail, because the wallet requires setting
	// of this param to prevent accidental overwrite of labels.
	_, err = ainz.WalletKitClient.LabelTransaction(
		ctxt, &walletrpc.LabelTransactionRequest{
			Txid:      sweepHash[:],
			Label:     "label that will not work",
			Overwrite: false,
		},
	)
	if err == nil {
		t.Fatalf("expected error for tx already labelled")
	}

	// Our error will be wrapped in a rpc error, so we check that it
	// contains the error we expect.
	if !strings.Contains(err.Error(), wallet.ErrTxLabelExists.Error()) {
		t.Fatalf("expected: label exists, got: %v", err)
	}

	// Finally, we overwrite our label with a new label, which should not
	// fail.
	newLabel := "new sweep tx label"
	_, err = ainz.WalletKitClient.LabelTransaction(
		ctxt, &walletrpc.LabelTransactionRequest{
			Txid:      sweepHash[:],
			Label:     newLabel,
			Overwrite: true,
		},
	)
	if err != nil {
		t.Fatalf("could not label tx: %v", err)
	}

	assertTxLabel(ctxb, t, ainz, sweepTxStr, newLabel)

	// Finally, Ainz should now have no coins at all within his wallet.
	balReq := &lnrpc.WalletBalanceRequest{}
	resp, err := ainz.WalletBalance(ctxt, balReq)
	if err != nil {
		t.Fatalf("unable to get ainz's balance: %v", err)
	}
	switch {
	case resp.ConfirmedBalance != 0:
		t.Fatalf("expected no confirmed balance, instead have %v",
			resp.ConfirmedBalance)

	case resp.UnconfirmedBalance != 0:
		t.Fatalf("expected no unconfirmed balance, instead have %v",
			resp.UnconfirmedBalance)
	}

	// If we try again, but this time specifying an amount, then the call
	// should fail.
	sweepReq.Amount = 10000
	_, err = ainz.SendCoins(ctxt, sweepReq)
	if err == nil {
		t.Fatalf("sweep attempt should fail")
	}
}

// TestLightningNetworkDaemon performs a series of integration tests amongst a
// programmatically driven network of lnd nodes.
func TestLightningNetworkDaemon(t *testing.T) {
	// If no tests are registered, then we can exit early.
	if len(allTestCases) == 0 {
		t.Skip("integration tests not selected with flag 'rpctest'")
	}

	// Parse testing flags that influence our test execution.
	logDir := lntest.GetLogDir()
	require.NoError(t, os.MkdirAll(logDir, 0700))
	testCases, trancheIndex, trancheOffset := getTestCaseSplitTranche()
	lntest.ApplyPortOffset(uint32(trancheIndex) * 1000)

	// Before we start any node, we need to make sure that any btcd node
	// that is started through the RPC harness uses a unique port as well to
	// avoid any port collisions.
	rpctest.ListenAddressGenerator = lntest.GenerateBtcdListenerAddresses

	// Declare the network harness here to gain access to its
	// 'OnTxAccepted' call back.
	var lndHarness *lntest.NetworkHarness

	// Create an instance of the btcd's rpctest.Harness that will act as
	// the miner for all tests. This will be used to fund the wallets of
	// the nodes within the test network and to drive blockchain related
	// events within the network. Revert the default setting of accepting
	// non-standard transactions on simnet to reject them. Transactions on
	// the lightning network should always be standard to get better
	// guarantees of getting included in to blocks.
	//
	// We will also connect it to our chain backend.
	minerLogDir := fmt.Sprintf("%s/.minerlogs", logDir)
	miner, minerCleanUp, err := lntest.NewMiner(
		minerLogDir, "output_btcd_miner.log", harnessNetParams,
		&rpcclient.NotificationHandlers{}, lntest.GetBtcdBinary(),
	)
	require.NoError(t, err, "failed to create new miner")
	defer func() {
		require.NoError(t, minerCleanUp(), "failed to clean up miner")
	}()

	// Start a chain backend.
	chainBackend, cleanUp, err := lntest.NewBackend(
		miner.P2PAddress(), harnessNetParams,
	)
	require.NoError(t, err, "new backend")
	defer func() {
		require.NoError(t, cleanUp(), "cleanup")
	}()

	// Before we start anything, we want to overwrite some of the connection
	// settings to make the tests more robust. We might need to restart the
	// miner while there are already blocks present, which will take a bit
	// longer than the 1 second the default settings amount to. Doubling
	// both values will give us retries up to 4 seconds.
	miner.MaxConnRetries = rpctest.DefaultMaxConnectionRetries * 2
	miner.ConnectionRetryTimeout = rpctest.DefaultConnectionRetryTimeout * 2

	// Set up miner and connect chain backend to it.
	require.NoError(t, miner.SetUp(true, 50))
	require.NoError(t, miner.Client.NotifyNewTransactions(false))
	require.NoError(t, chainBackend.ConnectMiner(), "connect miner")

	// Parse database backend
	var dbBackend lntest.DatabaseBackend
	switch *dbBackendFlag {
	case "bbolt":
		dbBackend = lntest.BackendBbolt

	case "etcd":
		dbBackend = lntest.BackendEtcd

	default:
		require.Fail(t, "unknown db backend")
	}

	// Now we can set up our test harness (LND instance), with the chain
	// backend we just created.
	ht := newHarnessTest(t, nil)
	binary := ht.getLndBinary()
	lndHarness, err = lntest.NewNetworkHarness(
		miner, chainBackend, binary, dbBackend,
	)
	if err != nil {
		ht.Fatalf("unable to create lightning network harness: %v", err)
	}
	defer lndHarness.Stop()

	// Spawn a new goroutine to watch for any fatal errors that any of the
	// running lnd processes encounter. If an error occurs, then the test
	// case should naturally as a result and we log the server error here to
	// help debug.
	go func() {
		for {
			select {
			case err, more := <-lndHarness.ProcessErrors():
				if !more {
					return
				}
				ht.Logf("lnd finished with error (stderr):\n%v",
					err)
			}
		}
	}()

	// Next mine enough blocks in order for segwit and the CSV package
	// soft-fork to activate on SimNet.
	numBlocks := harnessNetParams.MinerConfirmationWindow * 2
	if _, err := miner.Client.Generate(numBlocks); err != nil {
		ht.Fatalf("unable to generate blocks: %v", err)
	}

	// With the btcd harness created, we can now complete the
	// initialization of the network. args - list of lnd arguments,
	// example: "--debuglevel=debug"
	// TODO(roasbeef): create master balanced channel with all the monies?
	aliceBobArgs := []string{
		"--default-remote-max-htlcs=483",
	}

	// Run the subset of the test cases selected in this tranche.
	for idx, testCase := range testCases {
		testCase := testCase
		name := fmt.Sprintf("%02d-of-%d/%s/%s",
			trancheOffset+uint(idx)+1, len(allTestCases),
			chainBackend.Name(), testCase.name)

		success := t.Run(name, func(t1 *testing.T) {
			cleanTestCaseName := strings.ReplaceAll(
				testCase.name, " ", "_",
			)

			err = lndHarness.SetUp(
				t1, cleanTestCaseName, aliceBobArgs,
			)
			require.NoError(t1,
				err, "unable to set up test lightning network",
			)
			defer func() {
				require.NoError(t1, lndHarness.TearDown())
			}()

			lndHarness.EnsureConnected(
				context.Background(), t1,
				lndHarness.Alice, lndHarness.Bob,
			)

			logLine := fmt.Sprintf(
				"STARTING ============ %v ============\n",
				testCase.name,
			)

			AddToNodeLog(t, lndHarness.Alice, logLine)
			AddToNodeLog(t, lndHarness.Bob, logLine)

			// Start every test with the default static fee estimate.
			lndHarness.SetFeeEstimate(12500)

			// Create a separate harness test for the testcase to
			// avoid overwriting the external harness test that is
			// tied to the parent test.
			ht := newHarnessTest(t1, lndHarness)
			ht.RunTestCase(testCase)
		})

		// Stop at the first failure. Mimic behavior of original test
		// framework.
		if !success {
			// Log failure time to help relate the lnd logs to the
			// failure.
			t.Logf("Failure time: %v", time.Now().Format(
				"2006-01-02 15:04:05.000",
			))
			break
		}
	}
}