multi: move itest out of lntest

This commit moves all the test cases living in `itest` out of `lntest`,
further making `lntest` an independent package for general testing.

itest/lnd_trackpayments_test.go

@@ -0,0 +1,89 @@
+package itest
+
+import (
+	"encoding/hex"
+	"time"
+
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
+	"github.com/lightningnetwork/lnd/lntemp"
+	"github.com/stretchr/testify/require"
+)
+
+// testTrackPayments tests whether a client that calls the TrackPayments api
+// receives payment updates.
+func testTrackPayments(ht *lntemp.HarnessTest) {
+	// Open a channel between alice and bob.
+	alice, bob := ht.Alice, ht.Bob
+	channel := ht.OpenChannel(
+		alice, bob, lntemp.OpenChannelParams{
+			Amt: btcutil.Amount(300000),
+		},
+	)
+
+	// Call the TrackPayments api to listen for payment updates.
+	req := &routerrpc.TrackPaymentsRequest{
+		NoInflightUpdates: false,
+	}
+	tracker := alice.RPC.TrackPayments(req)
+
+	// Create an invoice from bob.
+	var amountMsat int64 = 1000
+	invoiceResp := bob.RPC.AddInvoice(
+		&lnrpc.Invoice{
+			ValueMsat: amountMsat,
+		},
+	)
+	invoice := bob.RPC.LookupInvoice(invoiceResp.RHash)
+
+	// Send payment from alice to bob.
+	paymentClient := alice.RPC.SendPayment(
+		&routerrpc.SendPaymentRequest{
+			PaymentRequest: invoice.PaymentRequest,
+			TimeoutSeconds: 60,
+		},
+	)
+
+	// Make sure the payment doesn't error due to invalid parameters or so.
+	_, err := paymentClient.Recv()
+	require.NoError(ht, err, "unable to get payment update.")
+
+	// Assert the first payment update is an inflight update.
+	update1, err := tracker.Recv()
+	require.NoError(ht, err, "unable to receive payment update 1.")
+
+	require.Equal(
+		ht, lnrpc.PaymentFailureReason_FAILURE_REASON_NONE,
+		update1.FailureReason,
+	)
+	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, update1.Status)
+	require.Equal(ht, invoice.PaymentRequest, update1.PaymentRequest)
+	require.Equal(ht, amountMsat, update1.ValueMsat)
+
+	// Assert the second payment update is a payment success update.
+	update2, err := tracker.Recv()
+	require.NoError(ht, err, "unable to receive payment update 2.")
+
+	require.Equal(
+		ht, lnrpc.PaymentFailureReason_FAILURE_REASON_NONE,
+		update2.FailureReason,
+	)
+	require.Equal(ht, lnrpc.Payment_SUCCEEDED, update2.Status)
+	require.Equal(ht, invoice.PaymentRequest, update2.PaymentRequest)
+	require.Equal(ht, amountMsat, update2.ValueMsat)
+	require.Equal(
+		ht, hex.EncodeToString(invoice.RPreimage),
+		update2.PaymentPreimage,
+	)
+
+	// TODO(yy): remove the sleep once the following bug is fixed.
+	// When the invoice is reported settled, the commitment dance is not
+	// yet finished, which can cause an error when closing the channel,
+	// saying there's active HTLCs. We need to investigate this issue and
+	// reverse the order to, first finish the commitment dance, then report
+	// the invoice as settled.
+	time.Sleep(2 * time.Second)
+
+	ht.CloseChannel(alice, channel)
+}