itest+lntest: use system wide unique ports everywhere

With this commit we create a new function that returns system wide
unique ports by using a single file to keep track of previously used
ports. We'll want to use this everywhere whenever we need to listen on a
new, random port during unit or integration tests.
Because we now have a unique source, we don't need to apply the port
offset that was used for the different tranches of parallel running
integration tests before.

itest/lnd_etcd_failover_test.go

@@ -13,7 +13,7 @@ import (
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lntest"
-	"github.com/lightningnetwork/lnd/lntest/node"
+	"github.com/lightningnetwork/lnd/lntest/port"
 	"github.com/stretchr/testify/require"
 )
 
@@ -56,8 +56,8 @@ func testEtcdFailover(ht *lntest.HarnessTest) {
 
 func testEtcdFailoverCase(ht *lntest.HarnessTest, kill bool) {
 	etcdCfg, cleanup, err := kvdb.StartEtcdTestBackend(
-		ht.T.TempDir(), uint16(node.NextAvailablePort()),
-		uint16(node.NextAvailablePort()), "",
+		ht.T.TempDir(), uint16(port.NextAvailablePort()),
+		uint16(port.NextAvailablePort()), "",
 	)
 	require.NoError(ht, err, "Failed to start etcd instance")
 	defer cleanup()

itest/lnd_network_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lntest"
 	"github.com/lightningnetwork/lnd/lntest/node"
+	"github.com/lightningnetwork/lnd/lntest/port"
 	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/stretchr/testify/require"
 )
@@ -111,7 +112,7 @@ func testReconnectAfterIPChange(ht *lntest.HarnessTest) {
 
 	// We derive an extra port for Dave, and we initialise his node with
 	// the port advertised as `--externalip` arguments.
-	ip2 := node.NextAvailablePort()
+	ip2 := port.NextAvailablePort()
 
 	// Create a new node, Dave, which will initialize a P2P port for him.
 	daveArgs := []string{fmt.Sprintf("--externalip=127.0.0.1:%d", ip2)}
@@ -190,7 +191,7 @@ func testReconnectAfterIPChange(ht *lntest.HarnessTest) {
 	// address.
 
 	// Change Dave's listening port and restart.
-	dave.Cfg.P2PPort = node.NextAvailablePort()
+	dave.Cfg.P2PPort = port.NextAvailablePort()
 	dave.Cfg.ExtraArgs = []string{
 		fmt.Sprintf(
 			"--externalip=127.0.0.1:%d", dave.Cfg.P2PPort,

itest/lnd_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lntest"
 	"github.com/lightningnetwork/lnd/lntest/node"
+	"github.com/lightningnetwork/lnd/lntest/port"
 	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc/grpclog"
@@ -90,7 +91,6 @@ func TestLightningNetworkDaemon(t *testing.T) {
 
 	// Get the test cases to be run in this tranche.
 	testCases, trancheIndex, trancheOffset := getTestCaseSplitTranche()
-	node.ApplyPortOffset(uint32(trancheIndex) * 1000)
 
 	// Create a simple fee service.
 	feeService := lntest.NewFeeService(t)
@@ -216,9 +216,10 @@ func init() {
 	// Before we start any node, we need to make sure that any btcd node
 	// that is started through the RPC harness uses a unique port as well
 	// to avoid any port collisions.
-	rpctest.ListenAddressGenerator = node.GenerateBtcdListenerAddresses
+	rpctest.ListenAddressGenerator =
+		port.GenerateSystemUniqueListenerAddresses
 
-	// Swap out grpc's default logger with out fake logger which drops the
+	// Swap out grpc's default logger with our fake logger which drops the
 	// statements on the floor.
 	fakeLogger := grpclog.NewLoggerV2(io.Discard, io.Discard, io.Discard)
 	grpclog.SetLoggerV2(fakeLogger)

itest/lnd_watchtower_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnrpc/wtclientrpc"
 	"github.com/lightningnetwork/lnd/lntest"
 	"github.com/lightningnetwork/lnd/lntest/node"
+	"github.com/lightningnetwork/lnd/lntest/port"
 	"github.com/lightningnetwork/lnd/lntest/rpc"
 	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/stretchr/testify/require"
@@ -595,7 +596,7 @@ func testRevokedCloseRetributionAltruistWatchtowerCase(ht *lntest.HarnessTest,
 func setUpNewTower(ht *lntest.HarnessTest, name, externalIP string) ([]byte,
 	string, *rpc.HarnessRPC) {
 
-	port := node.NextAvailablePort()
+	port := port.NextAvailablePort()
 
 	listenAddr := fmt.Sprintf("0.0.0.0:%d", port)