mongo_uri_test.cpp fails on systems without DNS resolvers.
Specifically the valid URLs starting with `mongodb+srv://` test cases result in calling `dns::lookupSRVRecords("_mongodb._tcp." + canonicalHost)` which bombs out, on systems with (intentionally) broken DNS.
It would be nice if that call is somehow mocked, or stubbed out, or some test responses are provided, to exercise tests on "offline" machines.
ps. Long story short, DNS resolution is disabled on Ubuntu builders.
pss. Longer story: I was told that Kees Cook asserted that it is a security vulnerability to James Troup, when I guess work was being done to create Launchpad PPAs, which would run untrusted code builds. James Troup asked for a proof of concept, and Kees Cook established two-way communication and got a shell up inside the builder over DNS queries to his nameserver. Ever since then DNS resolution was disabled on the Ubuntu builders. I don't know if this is true or not, but that's what I've been told.
In the meantime, I will disable the expected success mongodb+srv:// test cases from the build.