Add mailservers to transport object

protocol/transport/whisper_service.go

@@ -10,8 +10,8 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/ethereum/go-ethereum/p2p"
 	gethnode "github.com/ethereum/go-ethereum/node"
+	"github.com/ethereum/go-ethereum/p2p"
 
 	"github.com/status-im/status-go/services/shhext"
 	whisper "github.com/status-im/whisper/whisperv6"
@@ -19,6 +19,11 @@ import (
 	"github.com/status-im/status-console-client/protocol/subscription"
 )
 
+var (
+	// ErrNoMailservers returned if there is no configured mailservers that can be used.
+	ErrNoMailservers = errors.New("no configured mailservers")
+)
+
 type WhisperServiceKeysManager struct {
 	shh *whisper.Whisper
 
@@ -89,6 +94,7 @@ func NewWhisperServiceTransport(
 	return &WhisperServiceTransport{
 		node:        node,
 		shh:         shh,
+		mailservers: mailservers,
 		shhextAPI:   shhext.NewPublicAPI(shhextService),
 		keysManager: &WhisperServiceKeysManager{
 			shh:               shh,
@@ -184,6 +190,9 @@ func (a *WhisperServiceTransport) selectAndAddMailServer() (string, error) {
 	if a.selectedMailServerEnode != "" {
 		return a.selectedMailServerEnode, nil
 	}
+	if len(a.mailservers) == 0 {
+		return "", ErrNoMailservers
+	}
 
 	enode := randomItem(a.mailservers)
 	errCh := waitForPeerAsync(

protocol/transport/whisper_service_test.go

@@ -0,0 +1,14 @@
+package transport
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestSelectAndAddNoMailservers(t *testing.T) {
+	svc := &WhisperServiceTransport{}
+	rst, err := svc.selectAndAddMailServer()
+	require.Empty(t, rst)
+	require.EqualError(t, ErrNoMailservers, err.Error())
+}