Three tests in ServerFilesTests failing with Akka HTTP 10.5+

[honzabazant]

Situation:

• Our company obtained license from Lightbend so that we can use the latest Akka libraries
• We are using Tapir and Scala 3 and we build our version of tapir-akka-http-server for Scala 3 with the latest Akka
• As part of build, we run tests in the tapir-akka-http-server project to verify that our changes work.

Problem:
The following three tests in ServerFilesTests fail since Akka HTTP 10.5:

• should return acceptRanges for file head request
• should handle ranged HEAD request like a GET request
• should return acceptRanges for resource head request

The reason is that these tests expect the Content-Length header to be returned, but Akka HTTP does not return it for HEAD requests anymore (see akka/akka-http#4214).

According to RFC, this behaviour seems to be valid:

A server MAY send a Content-Length header field in a response to a HEAD request (Section 9.3.2); a server MUST NOT send Content-Length in such a response unless its field value equals the decimal number of octets that would have been sent in the content of a response if the same request had used the GET method.

Our workaround is easy (we just comment out the failing assertions), but I wonder if these assertions could be changed to match the RFC so that:

• if the Content-Length header is not present in the response, it is fine
• if the header is present, its value must match expectation.

Thank you

[adamw]

Sure, this sounds reasonable. Maybe we should add a supportContentLengthInHeadRequests so that we might configure the testsuite for both cases? And only the akka one would use false there.

Maybe you'd be open to creating a PR?

[honzabazant]

Yes, I will do my best :-)

[honzabazant]

I have submitted a PR, I hope I did it correctly.

This is my first Github PR ever, so any feedback is welcome :-)