fix: handle read preferences without tags

Author: zookzook

lib/mongo/url_parser.ex

@@ -236,6 +236,10 @@ defmodule Mongo.UrlParser do
  end
  end
 
+ defp parse_tags([]) do
+ []
+ end
+
  defp parse_tags(tags) do
  tags
  |> String.split(",")

test/mongo/url_parser_test.exs

@@ -124,6 +124,15 @@ defmodule Mongo.UrlParserTest do
  ]
  ]
 
+ assert UrlParser.parse_url(url: "mongodb://seed1.domain.com:27017,seed2.domain.com:27017/db_name?readPreference=secondary&maxStalenessSeconds=30") == [
+ database: "db_name",
+ read_preference: %{mode: :secondary, max_staleness_ms: 30_000},
+ seeds: [
+ "seed1.domain.com:27017",
+ "seed2.domain.com:27017"
+ ]
+ ]
+
  assert UrlParser.parse_url(url: "mongodb://seed1.domain.com:27017,seed2.domain.com:27017/db_name?readPreference=weird&readPreferenceTags=dc:ny,rack:r&maxStalenessSeconds=30") == [
  database: "db_name",
  seeds: [