accept empty dsn

Author: asmyasnikov

connection.go

@@ -253,6 +253,9 @@ func open(ctx context.Context, opts ...Option) (_ Connection, err error) {
 		}
 	}
 	for _, opt := range opts {
+		if opt == nil {
+			continue
+		}
 		err = opt(ctx, c)
 		if err != nil {
 			return nil, xerrors.WithStackTrace(err)

options.go

@@ -62,6 +62,9 @@ func WithRequestsType(requestsType string) Option {
 // Warning: WithConnectionString will be removed at next major release
 // (connection string will be required string param of ydb.Open)
 func WithConnectionString(connectionString string) Option {
+	if connectionString == "" {
+		return nil
+	}
 	return func(ctx context.Context, c *connection) error {
 		options, err := dsn.Parse(connectionString)
 		if err != nil {

test/connection_test.go

@@ -64,7 +64,8 @@ func TestConnection(t *testing.T) {
 	defer cancel()
 	db, err := ydb.Open(
 		ctx,
-		os.Getenv("YDB_CONNECTION_STRING"),
+		"", // corner case for check replacement of endpoint+database+secure
+		ydb.WithConnectionString(os.Getenv("YDB_CONNECTION_STRING")),
 		ydb.WithAnonymousCredentials(),
 		ydb.With(
 			config.WithOperationTimeout(time.Second*2),