cleanup manipulation of CQ/Cohort resource accounting in tests

[gabesaba]

What would you like to be cleaned:
We sometimes manipulate the internal accounting of ClusterQueue and Cohort snapshots. This is brittle. Quota/Lending Limit/Borrowing Limit/Usage should be set by calling public api methods, or by defining the CQs/Cohorts via API objects, adding to cache, and creating snapshot (see #2486 for an example).

See this thread #2486 (comment)

Why is this needed:
Tests are brittle, and make cache/snapshot hard to update

[alculquicondor]

Also #2486 (comment)

[gabesaba]

We also test against internal state of usage/quotas/limits. I will link those cleanup PRs to this issue as well.

[gabesaba]

• clusterqueue_test.go
• flavorassigner_test.go

These are the (hopefully) last two remaining. See #2583 for a complete example of refactoring test, changing ClusterQueueSnapshot to API type, and representing cohort capacity/usage via use of a 2nd cluster queue.

[highpon]

/assign

[gabesaba]

Thanks for helping with the cleanup, @highpon! Will you also be fixing flavorassigner_test.go?

[highpon]

Yes! I would love to work with you on flavorassigner_test.go as well!

[gabesaba]

Hi @highpon, will you still cleanup flavorassigner_test.go? If not, I will see if @vladikkuzn can work on it

[highpon]

@gabesaba
Sorry for the delay in responding!
I have now refactored the file up to the halfway point.
Three tests are failing. After fixing them, I will change the PR from Draft to Open.

[gabesaba]

Discussed over Slack with @highpon. @vladikkuzn, could you complete the remaining cleanup please?

/assign @vladikkuzn