itest: extend testAnchorReservedValue to open additional channels

We do this to trigger a bug that will be resolved in a follow-up commit.
This bug prevents inbound legacy channels from being rejected by the
recipient if they have at least one anchor channel already opened
without an on-chain balance.

lntest/itest/lnd_onchain_test.go

@@ -180,7 +180,8 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
 	err := net.ConnectNodes(ctxt, alice, bob)
 	require.NoError(t.t, err)
 
-	// Send just enough coins for Alice to open a channel without a change output.
+	// Send just enough coins for Alice to open a channel without a change
+	// output.
 	const (
 		chanAmt = 1000000
 		feeEst  = 8000
@@ -206,20 +207,45 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
 	// Alice opens a smaller channel. This works since it will have a
 	// change output.
 	ctxt, _ = context.WithTimeout(context.Background(), defaultTimeout)
-	aliceChanPoint := openChannelAndAssert(
+	aliceChanPoint1 := openChannelAndAssert(
 		ctxt, t, net, alice, bob,
 		lntest.OpenChannelParams{
-			Amt: chanAmt / 2,
+			Amt: chanAmt / 4,
 		},
 	)
 
-	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
+	// If Alice tries to open another anchor channel to Bob, Bob should not
-	err = alice.WaitForNetworkChannelOpen(ctxt, aliceChanPoint)
+	// reject it as he is not contributing any funds.
-	require.NoError(t.t, err)
+	aliceChanPoint2 := openChannelAndAssert(
+		ctxt, t, net, alice, bob, lntest.OpenChannelParams{
+			Amt: chanAmt / 4,
+		},
+	)
 
-	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
+	// Similarly, if Alice tries to open a legacy channel to Bob, Bob should
-	err = bob.WaitForNetworkChannelOpen(ctxt, aliceChanPoint)
+	// not reject it as he is not contributing any funds. We'll restart Bob
+	// to remove his support for anchors.
+	err = net.RestartNode(bob, nil)
 	require.NoError(t.t, err)
+	ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
+	aliceChanPoint3 := openChannelAndAssert(
+		ctxt, t, net, alice, bob, lntest.OpenChannelParams{
+			Amt: chanAmt / 4,
+		},
+	)
+
+	chanPoints := []*lnrpc.ChannelPoint{
+		aliceChanPoint1, aliceChanPoint2, aliceChanPoint3,
+	}
+	for _, chanPoint := range chanPoints {
+		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
+		err = alice.WaitForNetworkChannelOpen(ctxt, chanPoint)
+		require.NoError(t.t, err)
+
+		ctxt, _ = context.WithTimeout(ctxb, defaultTimeout)
+		err = bob.WaitForNetworkChannelOpen(ctxt, chanPoint)
+		require.NoError(t.t, err)
+	}
 
 	// Alice tries to send all coins to an internal address. This is
 	// allowed, since the final wallet balance will still be above the
@@ -317,7 +343,9 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
 
 	// Alice closes channel, should now be allowed to send everything to an
 	// external address.
-	closeChannelAndAssert(ctxt, t, net, alice, aliceChanPoint, false)
+	for _, chanPoint := range chanPoints {
+		closeChannelAndAssert(ctxt, t, net, alice, chanPoint, false)
+	}
 
 	newBalance := waitForConfirmedBalance()
 	if newBalance <= aliceBalance {
@@ -339,11 +367,11 @@ func testAnchorReservedValue(net *lntest.NetworkHarness, t *harnessTest) {
 	// generated above.
 	block = mineBlocks(t, net, 1, 1)[0]
 
-	// The sweep transaction should have two inputs, the change output from
+	// The sweep transaction should have four inputs, the change output from
-	// the previous sweep, and the output from the coop closed channel.
+	// the previous sweep, and the outputs from the coop closed channels.
 	sweepTx = block.Transactions[1]
-	if len(sweepTx.TxIn) != 2 {
+	if len(sweepTx.TxIn) != 4 {
-		t.Fatalf("expected 2 inputs instead have %v", len(sweepTx.TxIn))
+		t.Fatalf("expected 4 inputs instead have %v", len(sweepTx.TxIn))
 	}
 
 	// It should have a single output.