Specify port in 'Test_isValidResolvConf'

[b-long]

Proposed Changes

This PR expands testing of the 'Valid ResolvConf' scenario (pkg/agent/config/config_internal_test.go).

Types of Changes

New Feature

*I was not able to run tests locally, so I'm opening a pull request for the explicit purpose of running tests in CI. I'd like to know whether or not port numbers are supported, when installing with the --resolv-conf flag.

In other words, where an end-user might run a DNS server on an alternate port, and provide that number in a configuration file (e.g./etc/rancher/k3s/resolv.conf ) when installing like the following:

curl -sfL https://get.k3s.io | sh -s - --write-kubeconfig-mode 644 --resolv-conf /etc/rancher/k3s/resolv.conf

Verification

If CI passes, I expect that to be enough verification.

Testing

Yes.

Linked Issues

N/A

User-Facing Change

NONE

Further Comments

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.33%. Comparing base (37830fe) to head (0b237fc).
Report is 5 commits behind head on master.

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HEAD has 3 uploads less than BASE

Flag	BASE (37830fe)	HEAD (0b237fc)
e2etests	9	6

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10532      +/-   ##
==========================================
- Coverage   49.66%   43.33%   -6.33%     
==========================================
  Files         179      179              
  Lines       14936    14936              
==========================================
- Hits         7418     6473     -945     
- Misses       6158     7265    +1107     
+ Partials     1360     1198     -162     

Flag	Coverage Δ
e2etests	36.32% <ø> (-10.26%)	⬇️
inttests	19.72% <ø> (ø)
unittests	13.35% <ø> (ø)

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[b-long]

I just want to mention to the maintainers, as I understand it from my own local testing, running a DNS service on port 5300 and specifying it in /etc/rancher/k3s/resolv.conf was not respected.

Can anyone confirm?

That said, I do not recommend this PR to be merged since it seems the tests passing are a false positive.