duck/test: add initial tests for missing functions

[cpanato]

Fixes #4961

Proposed Changes

• 🎁 Add initial tests for pkg/duck

Pre-review Checklist

• At least 80% unit test coverage
• E2E tests for any new behavior
• Docs PR for any user-facing impact
• Spec PR for any new API feature
• Conformance test for any change to the spec

Release Note

NONE

Docs

[knative-prow-robot]

Welcome @cpanato! It looks like this is your first PR to knative/eventing 🎉

[knative-prow-robot]

Hi @cpanato. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[cpanato]

/assign @n3wscott

I'm very new to this project and did not fully understand it yet, the tests is reusing other parts of the existing tests

[matzew]

/ok-to-test

[knative-metrics-robot]

The following is the coverage report on the affected files.
Say /test pull-knative-eventing-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/duck/channel.go	76.7%	81.4%	4.7
pkg/duck/listable.go	54.7%	88.7%	34.0

[codecov]

Codecov Report

Merging #5367 (73b9680) into main (88d8a3e) will increase coverage by 0.29%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #5367      +/-   ##
==========================================
+ Coverage   82.35%   82.65%   +0.29%     
==========================================
  Files         194      194              
  Lines        6002     6002              
==========================================
+ Hits         4943     4961      +18     
+ Misses        737      717      -20     
- Partials      322      324       +2     

Impacted Files	Coverage Δ
pkg/duck/channel.go	63.63% <0.00%> (+9.09%)	⬆️
pkg/duck/listable.go	83.09% <0.00%> (+19.71%)	⬆️

---

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[n3wscott]

Looks like a fine test to me!! thanks so much @cpanato and welcome to Knative :D

/lgtm
/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: n3wscott

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