lntest+itest: add new method AssertChannelInGraph

This commit replaces `AssertTopologyChannelOpen` with
`AssertChannelInGraph`, which asserts a given channel edge is found.
`AssertTopologyChannelOpen` only asserts a given edge has been received
via the topology subscription, while we need to make sure the channel is
in the graph before continuing our tests.

itest/lnd_routing_test.go

@@ -344,7 +344,7 @@ func runMultiHopSendToRoute(ht *lntest.HarnessTest, useGraphCache bool) {
 	defer ht.CloseChannel(carol, chanPointBob)
 
 	// Make sure Alice knows the channel between Bob and Carol.
-	ht.AssertTopologyChannelOpen(alice, chanPointBob)
+	ht.AssertChannelInGraph(alice, chanPointBob)
 
 	// Create 5 invoices for Carol, which expect a payment from Alice for
 	// 1k satoshis with a different preimage each time.
@@ -965,7 +965,7 @@ func testMultiHopOverPrivateChannels(ht *lntest.HarnessTest) {
 	)
 
 	// Alice should know the new channel from Bob.
-	ht.AssertTopologyChannelOpen(alice, chanPointBob)
+	ht.AssertChannelInGraph(alice, chanPointBob)
 
 	// Next, we'll create Dave's node and open a private channel between
 	// him and Carol with Carol being the funder.
@@ -981,7 +981,7 @@ func testMultiHopOverPrivateChannels(ht *lntest.HarnessTest) {
 	)
 
 	// Dave should know the channel[Bob<->Carol] from Carol.
-	ht.AssertTopologyChannelOpen(dave, chanPointBob)
+	ht.AssertChannelInGraph(dave, chanPointBob)
 
 	// Now that all the channels are set up according to the topology from
 	// above, we can proceed to test payments. We'll create an invoice for
@@ -1077,8 +1077,8 @@ func testQueryRoutes(ht *lntest.HarnessTest) {
 
 	// Before we continue, give Alice some time to catch up with the newly
 	// opened channels.
-	ht.AssertTopologyChannelOpen(alice, chanPointBob)
-	ht.AssertTopologyChannelOpen(alice, chanPointCarol)
+	ht.AssertChannelInGraph(alice, chanPointBob)
+	ht.AssertChannelInGraph(alice, chanPointCarol)
 
 	// Query for routes to pay from Alice to Dave.
 	const paymentAmt = 1000
@@ -1389,7 +1389,7 @@ func testRouteFeeCutoff(ht *lntest.HarnessTest) {
 	}
 	for _, chanPoint := range networkChans {
 		for _, node := range nodes {
-			ht.AssertTopologyChannelOpen(node, chanPoint)
+			ht.AssertChannelInGraph(node, chanPoint)
 		}
 	}