Add unit tests for VM converter and remove unused err from SDKToVM

[willie-yao]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR adds unit tests for the VM converter and removes unused err return from SDKToVM

Which issue(s) this PR fixes:
Fixes #2538

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

NONE

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: willie-yao / name: William Yao (01ac161)

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @willie-yao. Thanks for your PR.

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[mboersma]

/ok-to-test

[willie-yao]

/retest

[willie-yao]

/retest

[Jont828]

By the way since the VM converter never actually returns an error I think could probably just remove it from the function spec. Wdyt about that?

[willie-yao]

I agree with that. Should we do that in a separate PR?

[mboersma]

the VM converter never actually returns an error...just remove it from the spec

Should we do that in a separate PR?

My test for that is "is there a possibility we might need to revert these changes separately?" That illuminates whether the changes are logically distinct and ought to have separate commits and PRs.

In this case, the changes are distinct, but I think there's little chance we would need to revert them separately. So IMHO it's a judgment call. It's always defensible to make separate PRs, but I think you could make both changes in one PR in this case and reviewers wouldn't complain...at least I wouldn't. 😄

This lgtm, btw.

[willie-yao]

@mboersma @Jont828 Just pushed changes removing the unused err from SDKToVM. Let me know if this looks good, and I'll squash it. I figured I'd include it in this PR since it changes the test somewhat significantly.

[mboersma]

Hmm...so changing the signature of SDKToVM is actually a public-facing API change, so apidiff is correct. I think it's entirely likely that no one is consuming that API beyond the single reference that you updated in this PR, but we can't be sure.

Maybe I was wrong about combining the two commits? I'm curious what other reviewers think. ping @Jont828 @CecileRobertMichon @jackfrancis

[willie-yao]

@mboersma That's correct. One interesting thing is that my PR to change the apidiff test would have made this test pass, since we are changing that test to only flag breaking changes within the api/ or exp/api/ directories. I'm assuming this means that this change would be okay to merge?

[mboersma]

You are correct, I totally forgot that we really only care about those dirs for apidiff. (#2567 can't merge soon enough.)

[mboersma]

@willie-yao if you can rebase this to fix the apidiff error, I think it's good to merge.

[mboersma]

/lgtm

[CecileRobertMichon]

/lgtm
/approve

great work 🎉

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CecileRobertMichon

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