lntest: add InvoiceAcceptor support to node RPC harness

This commit enhances the itest LND node harness to include support for
the new `InvoiceAcceptor` RPC endpoint.

Author: ffranr

lntest/harness.go

@@ -16,6 +16,7 @@ import (
 	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/kvdb/etcd"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
 	"github.com/lightningnetwork/lnd/lntest/node"
@@ -2183,6 +2184,39 @@ func (h *HarnessTest) ReceiveHtlcInterceptor(
 	return nil
 }
 
+// ReceiveInvoiceAcceptor waits until a message is received on the invoice
+// acceptor interceptor stream or the timeout is reached.
+func (h *HarnessTest) ReceiveInvoiceAcceptor(
+	stream rpc.InvoiceAcceptorClient) *invoicesrpc.InvoiceAcceptorRequest {
+
+	chanMsg := make(chan *invoicesrpc.InvoiceAcceptorRequest)
+	errChan := make(chan error)
+	go func() {
+		// Consume one message. This will block until the message is
+		// received.
+		resp, err := stream.Recv()
+		if err != nil {
+			errChan <- err
+			return
+		}
+		chanMsg <- resp
+	}()
+
+	select {
+	case <-time.After(DefaultTimeout):
+		require.Fail(h, "timeout", "timeout invoice acceptor")
+
+	case err := <-errChan:
+		require.Failf(h, "err from stream",
+			"received err from stream: %v", err)
+
+	case updateMsg := <-chanMsg:
+		return updateMsg
+	}
+
+	return nil
+}
+
 // ReceiveChannelEvent waits until a message is received from the
 // ChannelEventsClient stream or the timeout is reached.
 func (h *HarnessTest) ReceiveChannelEvent(

lntest/rpc/router.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
 	"github.com/stretchr/testify/require"
 )
@@ -193,6 +194,23 @@ func (h *HarnessRPC) HtlcInterceptor() (InterceptorClient, context.CancelFunc) {
 	return resp, cancel
 }
 
+type InvoiceAcceptorClient invoicesrpc.Invoices_InvoiceAcceptorClient
+
+// InvoiceAcceptor makes an RPC call to the node's RouterClient and asserts.
+func (h *HarnessRPC) InvoiceAcceptor() (InvoiceAcceptorClient,
+	context.CancelFunc) {
+
+	// InvoiceAcceptor needs to have the context alive for the entire test
+	// case as the returned client will be used for send and receive events
+	// stream. Therefore, we use cancel context here instead of a timeout
+	// context.
+	ctxt, cancel := context.WithCancel(h.runCtx)
+	resp, err := h.Invoice.InvoiceAcceptor(ctxt)
+	h.NoError(err, "InvoiceAcceptor")
+
+	return resp, cancel
+}
+
 type TrackPaymentsClient routerrpc.Router_TrackPaymentsClient
 
 // TrackPayments makes a RPC call to the node's RouterClient and asserts.