lnwallet/interface_test: wait for bitcoind startup

Flakes locally for me on darwin.

lnwallet/interface_test.go

@@ -38,6 +38,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb/kvdb"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
+	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
@@ -3062,18 +3063,22 @@ func runTests(t *testing.T, walletDriver *lnwallet.WalletDriver,
 			defer bitcoind.Process.Kill()
 
 			// Wait for the bitcoind instance to start up.
-			time.Sleep(time.Second)
 
 			host := fmt.Sprintf("127.0.0.1:%d", rpcPort)
-			chainConn, err := chain.NewBitcoindConn(
+			var chainConn *chain.BitcoindConn
-				netParams, host, "weks", "weks", zmqBlockHost,
+			err = wait.NoError(func() error {
-				zmqTxHost, 100*time.Millisecond,
+				chainConn, err = chain.NewBitcoindConn(
+					netParams, host, "weks", "weks",
+					zmqBlockHost, zmqTxHost,
+					100*time.Millisecond,
 				)
 				if err != nil {
-				t.Fatalf("unable to establish connection to "+
+					return err
-					"bitcoind: %v", err)
 				}
-			if err := chainConn.Start(); err != nil {
+
+				return chainConn.Start()
+			}, 10*time.Second)
+			if err != nil {
 				t.Fatalf("unable to establish connection to "+
 					"bitcoind: %v", err)
 			}