itest: add flags for lnd executable

lntest/itest/lnd_test.go

@@ -14,7 +14,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"runtime"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -14213,23 +14212,9 @@ func TestLightningNetworkDaemon(t *testing.T) {
 		t, chainBackend.ConnectMiner(), "failed to connect to miner",
 	)
 
-	binary := itestLndBinary
-	if runtime.GOOS == "windows" {
-		// Windows (even in a bash like environment like git bash as on
-		// Travis) doesn't seem to like relative paths to exe files...
-		currentDir, err := os.Getwd()
-		if err != nil {
-			ht.Fatalf("unable to get working directory: %v", err)
-		}
-		targetPath := filepath.Join(currentDir, "../../lnd-itest.exe")
-		binary, err = filepath.Abs(targetPath)
-		if err != nil {
-			ht.Fatalf("unable to get absolute path: %v", err)
-		}
-	}
-
 	// Now we can set up our test harness (LND instance), with the chain
 	// backend we just created.
+	binary := ht.getLndBinary()
 	lndHarness, err = lntest.NewNetworkHarness(miner, chainBackend, binary)
 	if err != nil {
 		ht.Fatalf("unable to create lightning network harness: %v", err)

lntest/itest/test_harness.go

@@ -3,8 +3,12 @@ package itest
 import (
 	"bytes"
 	"context"
+	"flag"
 	"fmt"
 	"math"
+	"os"
+	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -20,6 +24,11 @@ import (
 
 var (
 	harnessNetParams = &chaincfg.RegressionNetParams
+
+	// lndExecutable is the full path to the lnd binary.
+	lndExecutable = flag.String(
+		"lndexec", itestLndBinary, "full path to lnd binary",
+	)
 )
 
 const (
@@ -111,6 +120,31 @@ func (h *harnessTest) Log(args ...interface{}) {
 	h.t.Log(args...)
 }
 
+func (h *harnessTest) getLndBinary() string {
+	binary := itestLndBinary
+	lndExec := ""
+	if lndExecutable != nil && *lndExecutable != "" {
+		lndExec = *lndExecutable
+	}
+	if lndExec == "" && runtime.GOOS == "windows" {
+		// Windows (even in a bash like environment like git bash as on
+		// Travis) doesn't seem to like relative paths to exe files...
+		currentDir, err := os.Getwd()
+		if err != nil {
+			h.Fatalf("unable to get working directory: %v", err)
+		}
+		targetPath := filepath.Join(currentDir, "../../lnd-itest.exe")
+		binary, err = filepath.Abs(targetPath)
+		if err != nil {
+			h.Fatalf("unable to get absolute path: %v", err)
+		}
+	} else if lndExec != "" {
+		binary = lndExec
+	}
+
+	return binary
+}
+
 type testCase struct {
 	name string
 	test func(net *lntest.NetworkHarness, t *harnessTest)