Good news: for cryptographic protocols and methods they are! Many of the cryptographic primitives that I implemented for my test TLS 1.3 implementation (https://github.com/syncsynchalt/tincan-tls) come with test vectors in the spec itself, and the rest always had test vectors supplied in a separate doc.

For an example see Appendix C of the AES standard, FIPS-197: https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197.pdf

In the case of TLS 1.3 I was able to use this IETF draft: https://tools.ietf.org/html/draft-ietf-tls-tls13-vectors-07