Add lib/go-atscfg unit test for HTTP_NO_CACHE with Topology on Mids

[rob05c]

Previously, HTTP_NO_CACHE Delivery Services skipped the Mids. With Topologies, a HTTP_NO_CACHE DS could use Mids.

The "no-caching" is done via cache.config. Looking at the config generation, it looks like it should be put on both Edge and Mid cache types. But since it wasn't possible for Mids before, we should add a unit test verifying that Mids and Edges both will get a correct "no-caching" entry in cache.config, for HTTP_NO_CACHE Topology DSes.

I'm submitting a ...

• improvement request (usability, performance, tech debt, etc.)

Traffic Control components affected ...

• Traffic Ops ORT

Current behavior:

No unit test exists for for HTTP_NO_CACHE Topology DSes creating config to not cache on Mids.

New behavior:

Unit test exists for for HTTP_NO_CACHE Topology DSes creating config to not cache on Mids.

Minimal reproduction of the problem with instructions:

Observe unit test doesn't exist.

Anything else:

[deepto98]

Can I pick this up? I'm new to the project, it would be really helpful if you can point me to some of the other unit tests I can look at.

[ocket8888]

The library responsible for configuration file generation is at lib/go-atscfg. The package lacks much in the way of developer docs (pending #6099). The task is theoretically simple, but you will need some understanding of how ATS works and you'll need familiarity with the basic function of ATC and Topologies in particular.