itest+lntest: add itest for Quiesce RPC method

itest/list_on_test.go

@@ -710,4 +710,8 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "experimental endorsement",
 		TestFunc: testExperimentalEndorsement,
 	},
+	{
+		Name:     "quiescence",
+		TestFunc: testQuiescence,
+	},
 }

itest/lnd_quiescence_test.go

@@ -0,0 +1,48 @@
+package itest
+
+import (
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/devrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
+	"github.com/lightningnetwork/lnd/lntest"
+	"github.com/stretchr/testify/require"
+)
+
+// testQuiescence tests whether we can come to agreement on quiescence of a
+// channel. We initiate quiescence via RPC and if it succeeds we verify that
+// the expected initiator is the resulting initiator.
+//
+// NOTE FOR REVIEW: this could be improved by blasting the channel with HTLC
+// traffic on both sides to increase the surface area of the change under test.
+func testQuiescence(ht *lntest.HarnessTest) {
+	alice, bob := ht.Alice, ht.Bob
+
+	chanPoint := ht.OpenChannel(bob, alice, lntest.OpenChannelParams{
+		Amt: btcutil.Amount(1000000),
+	})
+	defer ht.CloseChannel(bob, chanPoint)
+
+	res := alice.RPC.Quiesce(&devrpc.QuiescenceRequest{
+		ChanId: chanPoint,
+	})
+
+	require.True(ht, res.Initiator)
+
+	req := &routerrpc.SendPaymentRequest{
+		Dest:           ht.Alice.PubKey[:],
+		Amt:            100,
+		PaymentHash:    ht.Random32Bytes(),
+		FinalCltvDelta: finalCltvDelta,
+		TimeoutSeconds: 60,
+		FeeLimitMsat:   noFeeLimitMsat,
+	}
+
+	ht.SendPaymentAssertFail(
+		ht.Bob, req,
+		// This fails with insufficient balance because the bandwidth
+		// manager reports 0 bandwidth if a link is not eligible for
+		// forwarding, which is the case during quiescence.
+		lnrpc.PaymentFailureReason_FAILURE_REASON_INSUFFICIENT_BALANCE,
+	)
+}

lntest/rpc/lnd.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/devrpc"
 	"github.com/stretchr/testify/require"
 )
 
@@ -730,3 +731,17 @@ func (h *HarnessRPC) LookupHtlcResolutionAssertErr(
 
 	return err
 }
+
+// Quiesce makes an RPC call to the node's Quiesce method and returns the
+// response.
+func (h *HarnessRPC) Quiesce(
+	req *devrpc.QuiescenceRequest) *devrpc.QuiescenceResponse {
+
+	ctx, cancel := context.WithTimeout(h.runCtx, DefaultTimeout)
+	defer cancel()
+
+	res, err := h.Dev.Quiesce(ctx, req)
+	h.NoError(err, "Quiesce returned an error")
+
+	return res
+}