itest+lntest: add testLookupHTLC

itest/list_on_test.go

@@ -511,4 +511,8 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "async bidirectional payments",
 		TestFunc: testBidirectionalAsyncPayments,
 	},
+	{
+		Name:     "lookup htlc",
+		TestFunc: testLookupHTLC,
+	},
 }

itest/lnd_htlc_test.go

@@ -0,0 +1,71 @@
+package itest
+
+import (
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lntest"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// testLookupHTLC checks that `LookupHtlc` returns the correct HTLC
+// information.
+func testLookupHTLC(ht *lntest.HarnessTest) {
+	const chanAmt = btcutil.Amount(1000000)
+
+	alice := ht.Alice
+	carol := ht.NewNode("Carol", []string{
+		"--store-final-htlc-resolutions",
+	})
+	ht.EnsureConnected(alice, carol)
+
+	// Open a channel between Alice and Carol.
+	cp := ht.OpenChannel(
+		alice, carol, lntest.OpenChannelParams{Amt: chanAmt},
+	)
+
+	// Channel should be ready for payments.
+	const payAmt = 100
+
+	// Create an invoice.
+	invoice := &lnrpc.Invoice{
+		Memo:      "alice to carol htlc lookup",
+		RPreimage: ht.Random32Bytes(),
+		Value:     payAmt,
+	}
+
+	// Carol adds the invoice to her database.
+	resp := carol.RPC.AddInvoice(invoice)
+
+	// Subscribe the invoice.
+	stream := carol.RPC.SubscribeSingleInvoice(resp.RHash)
+
+	// Alice pays Carol's invoice.
+	ht.CompletePaymentRequests(alice, []string{resp.PaymentRequest})
+
+	// Carol waits until the invoice is settled.
+	ht.AssertInvoiceState(stream, lnrpc.Invoice_SETTLED)
+
+	// Get the channel using the assert function.
+	//
+	// TODO(yy): make `ht.OpenChannel` return lnrpc.Channel instead of
+	// lnrpc.ChannelPoint.
+	channel := ht.AssertChannelExists(carol, cp)
+
+	// Lookup the HTLC and assert the htlc is settled offchain.
+	req := &lnrpc.LookupHtlcRequest{
+		ChanId:    channel.ChanId,
+		HtlcIndex: 0,
+	}
+
+	// Check that Alice will get an error from LookupHtlc.
+	err := alice.RPC.LookupHtlcAssertErr(req)
+	gErr := status.Convert(err)
+	require.Equal(ht, codes.Unavailable, gErr.Code())
+
+	// Check that Carol can get the final htlc info.
+	finalHTLC := carol.RPC.LookupHtlc(req)
+	require.True(ht, finalHTLC.Settled, "htlc should be settled")
+	require.True(ht, finalHTLC.Offchain, "htlc should be Offchain")
+}

lntest/rpc/lnd.go

@@ -696,3 +696,29 @@ func (h *HarnessRPC) GetChanInfo(
 
 	return resp
 }
+
+// LookupHtlc makes a RPC call to the node's LookupHtlc and returns the
+// response.
+func (h *HarnessRPC) LookupHtlc(
+	req *lnrpc.LookupHtlcRequest) *lnrpc.LookupHtlcResponse {
+
+	ctxt, cancel := context.WithTimeout(h.runCtx, DefaultTimeout)
+	defer cancel()
+
+	resp, err := h.LN.LookupHtlc(ctxt, req)
+	h.NoError(err, "LookupHtlc")
+
+	return resp
+}
+
+// LookupHtlcAssertErr makes a RPC call to the node's LookupHtlc and asserts
+// an RPC error is returned.
+func (h *HarnessRPC) LookupHtlcAssertErr(req *lnrpc.LookupHtlcRequest) error {
+	ctxt, cancel := context.WithTimeout(h.runCtx, DefaultTimeout)
+	defer cancel()
+
+	_, err := h.LN.LookupHtlc(ctxt, req)
+	require.Error(h, err, "expected an error")
+
+	return err
+}