[Federation] Add type-agnostic e2e crud test

[marun]

This PR proposes an e2e test that reuses the type-agnostic crudtester already used for integration testing to validate crud against a deployed cluster. It is intended to to eventually replace the existing e2e tests for simple types like secrets, but for now will run in addition to the existing testing to gain confidence in the coverage it provides.

The deletion corner cases - when orphanDependents is nil or true - do not involve operations in the member clusters and are already well-tested in integration testing and so are not reimplemented here.

Where it can be applied, this approach of abstracting a test from its execution environment - making the test 'retargetable' - can reduce the cost of test development since the bulk of the work can be iterated on as an integration test. It can also serve as a check on assumptions made in the integration test about how a deployed environment will behave.

cc: @kubernetes/sig-federation-pr-reviews @kubernetes/sig-testing-misc @smarterclayton @derekwaynecarr

[k8s-reviewable]

This change is 

[madhusudancs]

@nikhiljindal assigning it to you because you are reviewing other integration test PRs and have better context about it.

[marun]

cc: @perotinus

[perotinus]

Does this need to be public? You could add a NewSecretAdapter method instead.

[marun]

Is there a reason to choose one approach over another? I've generally preferred to use factory methods only when more than simple assignment is required.

[perotinus]

This looks good overall. I do question whether the CRUDHelper should be in a separate package that is depended on by both integration and e2e tests: it seems more like a generic testing harness than something directly tied to either kind of test.

[marun]

@perotinus I agree that CRUDHelper should be separated, if only because otherwise any e2e using it will be pulling in everything needed to run federation and kubernetes api servers. I think having it live in something like test/integration/federation/crud could be ok, though. I don't think there is precedent for sharing test code between integration and e2e, and I'm not sure it makes sense to specialize its placement just yet.

[perotinus]

@marun Yes, that's kind of what I had in mind too. I think your idea of package structure is reasonable for now. I'm not familiar enough with the test tree to really know of a better place, though I could see either a federation subdir fixtures or utils being appropriate.

This LGTM.

[marun]

I've rebased this on top of #43500 to benefit from the refactoring it did, and switched to adding a new test instead of replacing the old one. My intent is to reduce the risk of losing coverage while the kinks in this approach are worked out.

[perotinus]

Why do you need to do this in the test block? Will GetClusterClients not work in the outer scope?

[marun]

Getting the cluster clients is an expensive operation. No point in doing it if the test will be skipped.

[perotinus]

LGTM.

[perotinus]

@csbell @nikhiljindal @madhusudancs Can someone else approve this?

[madhusudancs]

@k8s-bot pull-kubernetes-federation-e2e-gce test this

[marun]

@k8s-bot bazel test this

[marun]

rebased

@k8s-bot pull-kubernetes-federation-e2e-gce test this

[marun]

@csbell e2e is green: http://prow.k8s.io/?type=presubmit&pull=43194&job=pull-kubernetes-federation-e2e-gce

[csbell]

/lgtm

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: csbell, marun

Needs approval from an approver in each of these OWNERS Files:

• test/e2e_federation/OWNERS [csbell,marun]

You can indicate your approval by writing /approve in a comment
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[k8s-github-robot]

@k8s-bot test this [submit-queue is verifying that this PR is safe to merge]

[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 44519, 43194, 44513)

[k8s-ci-robot]

@marun: The following test(s) failed:

Test name	Commit	Details	Rerun command
Jenkins GCE e2e	d979210	link	@k8s-bot cvm gce e2e test this

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