One of the feedback items from the 4.2 retro was that SRV polling spec tests were incomplete (or lacking) and that the "initial implementation did not have any integration tests, [and] lots of drivers had to make up the tests."

I assume this refers to the Test Plan in the spec, which dates back to 49d2c8d (and old commit much earlier in the 4.2 dev cycle). That section also admits that testing is difficult because it involves modifying DNS records.

If any drivers were able to implement better integration tests for this feature, we'd do well to contribute those back into the spec so all languages can benefit.