Ask HN: Good language-agnostic test suites?

Are there any good language-agnostic test suites for common protocols and RFCs?

Any new programming language needs to implement libraries for things like JSON, Yaml, HTTP, MQTT, TLS, URL-parsing, etc.

Are there some good test-suites that explicitly test correct behavior for the most important RFCs? Maybe even an online service or docker container?

Is there an implementation that made these tests in such a way that they can be easily adapted for other programming languages?