Add missing test

integration_tests/lnd-mock.go

@@ -29,3 +29,30 @@ func NewLNDMockWrapper(lndOptions lnd.LNDoptions) (result *LNDMockWrapper, err e
 func (wrapper *LNDMockWrapper) SendPaymentSync(ctx context.Context, req *lnrpc.SendRequest, options ...grpc.CallOption) (*lnrpc.SendResponse, error) {
 	return nil, errors.New(SendPaymentMockError)
 }
+
+// mock where send payment sync failure is controlled by channel
+var errorMessageChannel = make(chan string, 1)
+
+type LNDMockWrapperAsync struct {
+	*lnd.LNDWrapper
+}
+
+func NewLNDMockWrapperAsync(lndOptions lnd.LNDoptions) (result *LNDMockWrapperAsync, err error) {
+	lnd, err := lnd.NewLNDclient(lndOptions)
+	if err != nil {
+		return nil, err
+	}
+
+	return &LNDMockWrapperAsync{
+		LNDWrapper: lnd,
+	}, nil
+}
+
+func (wrapper *LNDMockWrapperAsync) SendPaymentSync(ctx context.Context, req *lnrpc.SendRequest, options ...grpc.CallOption) (*lnrpc.SendResponse, error) {
+	errorMessage := <-errorMessageChannel
+	return nil, errors.New(errorMessage)
+}
+
+func (wrapper *LNDMockWrapperAsync) FailPayment(message string) {
+	errorMessageChannel <- message
+}