# correctly rejected
irb(main):002:0> a=Mongo::Client.new('mongodb+srv://hai.xx')

Mongo::Error::InvalidURI (Bad URI: mongodb+srv://hai.xx)
The domain name must consist of at least two parts: the domain name, and a TLD.
MongoDB URI must be in the following format: mongodb+srv://[username:password@]host[/[database][?options]]
Please see the following URL for more information: http://docs.mongodb.org/manual/reference/connection-string/

# incorrectly accepted
irb(main):004:0> a=Mongo::Client.new('mongodb+srv://hai.xx.')
Traceback (most recent call last):
       13: from /home/w/.rbenv/versions/2.6.1/bin/irb:23:in `<main>'
       12: from /home/w/.rbenv/versions/2.6.1/bin/irb:23:in `load'
       11: from /home/w/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/irb-1.0.0/exe/irb:11:in `<top (required)>'
       10: from (irb):4
        9: from (irb):4:in `rescue in irb_binding'
        8: from (irb):4:in `new'
        7: from /home/w/apps/ruby-driver/lib/mongo/client.rb:324:in `initialize'
        6: from /home/w/apps/ruby-driver/lib/mongo/uri.rb:221:in `get'
        5: from /home/w/apps/ruby-driver/lib/mongo/uri.rb:221:in `new'
        4: from /home/w/apps/ruby-driver/lib/mongo/uri.rb:258:in `initialize'
        3: from /home/w/apps/ruby-driver/lib/mongo/uri.rb:315:in `parse!'
        2: from /home/w/apps/ruby-driver/lib/mongo/uri/srv_protocol.rb:99:in `parse_creds_hosts!'
        1: from /home/w/apps/ruby-driver/lib/mongo/uri/srv_protocol.rb:122:in `get_records'
Mongo::Error::NoSRVRecords (The DNS query returned no SRV records at hostname (hai.xx.))

(byebug) query_name
"_mongodb._tcp.hai.xx."

(byebug) resolver.getresources('google.com.', Resolv::DNS::Resource::IN::A)
[#<Resolv::DNS::Resource::IN::A:0x000055be00775010 @address=#<Resolv::IPv4 172.217.7.14>, @ttl=5>]