[#1032] Added mock server integration

[vitaliihonta]

@adamw @ghostbuster91 added DRAFT implementation with mock-server .
You may try it by running mock-server locally in docker:

 docker run -d --name tapir-mock-server --rm -p 1080:1080 mockserver/mockserver

There are few questions about the implementation:

• I decided to communicate with the mock-server directly using REST API (so there are no dependency on java client which transitively depends on netty which may be an issue)
• It is required to use some json library to communicate with mock-server. What option should be choosed? Should we abstract over the library using tapir's JsonCodec
• How can we add tests? Would it be OK to use test-containers in CI to be sure? Or can it be just unit tests?

[vitaliihonta]

Probably can be refactored so that both sttp-stub-server and sttp-mock-server will use the same logic

[vitaliihonta]

I have no idea why doesn't it compile on the CI server 😢 Locally it runs successfully

[adamw]

I think using the REST API directly is definitely a good choice :) Same with circe - it doesn't bring in many dependencies so it's also a safe (and popular) choice.

As for the compile errors - maybe you rebased before pushing? There have been some changes to server interpreters, see the stub implementation (but shouldn't impact your impl much)

[vitaliihonta]

@adamw got it, I'll rebase my branch soon.
BTW about the tests. Actually, I can cover basic cases with just unit tests without testcontainers. It's not as reliable as integration tests with the latest mock-server version in docker, but it's a good start.

[vitaliihonta]

@adamw @ghostbuster91 I've added the most used functionality (creating strict expectations, verifying them, clearing, etc.). I would like to receive your feedback before I go further implementing tests 😄
P.S. Not sure why JVM suites timeouts...

[adamw]

Looks good - I don't think I have any significant comments :)

[adamw]

I guess for unit-testing you might end up stubbing the mock server ;)

[ghostbuster91]

Awesome, thanks for the great work :) I think we should also mention it somewhere in the docs, probably in testing section (https://github.com/softwaremill/tapir/blob/master/doc/testing.md)

[vitaliihonta]

@adamw @ghostbuster91 I'm done with unit tests and the documentation 😃
I hope it's OK so that you can merge it

[adamw]

Thank you!